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Manipulation of Nanoparticles and Nanotubes by Dieletrophoresis
ME 395
March 16 2004Ned Cameron Christine Darve Christina Freyman and Li Sun
Outline
bull Techniques for Separation
bull Electrodes
bull Stern Layer
bull Applications of DEP
bull Activities
bull Results
Separation Techniques
bull Electrophoresis - migration of charged molecules in an electrical field
bull Electroosmosis - the movement of liquid through a bed of particles by applying an electric field
bull Dielectrophoresis (DEP) - the manipulation of polarizable particles by non-uniform AC fields Non-invasive non-destructive alternating pulses at controllable frequency
Dielectrophoretic Force
bull DEP Force on the particlendash r = radius of particle
ndash εm= permittivity of medium
ndash Re[K(ω)]-real part of the Clausius-Mossotti factor
E - gradient of electric field
23 )](Re[2 EKrF mDEP
Clausius-Mossotti Factor
εm= complex permittivities of the medium
εp = complex permittivities of the particle
σ the conductivity ε the permittivity ω the angular frequency of the applied electric field j=-1 psurface conductance of particleradius of particle
If K(ω) gt 0 then particles move to regions of highest field strength - positive DEP
If K(ω) lt 0 then particles move to regions of lowest field strength - negative DEP
1
Activity 1 - Plotting Re[K(ω)] vs ω for 500 and 200 nm beads
A plot of the Clausius-Mossotti factor versus frequency for 216-nm- (dashed) and 557-nm-diameter (solid) latex particles with a particle permittivity p = 255 and a medium conductivity m = 1 mSm-1 The surface conductance was set at 232 nS for both sizes of particles
Morgan Hywel et al ldquoSeparation of Submicron Bioparticles by Dielectrophoresisrdquo Biophys J July 1999 p 516-525 Vol 77 No 1
Electrode Arrays and Electric Field Analysis
The Scaling Law
V ~ the applied voltage and Le ~the characteristic length of the electrodes
Deposit gold electrodes
Si Substrate
Electrode Fabrication amp Electrode Configuration
Parallel Tip-to-tip electrode array
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Castellated electrode array
N G Green and H Morgan Dielectrophoretic separation of nano-particles
J Phys D Appl Phys 30 (1997)
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Outline
bull Techniques for Separation
bull Electrodes
bull Stern Layer
bull Applications of DEP
bull Activities
bull Results
Separation Techniques
bull Electrophoresis - migration of charged molecules in an electrical field
bull Electroosmosis - the movement of liquid through a bed of particles by applying an electric field
bull Dielectrophoresis (DEP) - the manipulation of polarizable particles by non-uniform AC fields Non-invasive non-destructive alternating pulses at controllable frequency
Dielectrophoretic Force
bull DEP Force on the particlendash r = radius of particle
ndash εm= permittivity of medium
ndash Re[K(ω)]-real part of the Clausius-Mossotti factor
E - gradient of electric field
23 )](Re[2 EKrF mDEP
Clausius-Mossotti Factor
εm= complex permittivities of the medium
εp = complex permittivities of the particle
σ the conductivity ε the permittivity ω the angular frequency of the applied electric field j=-1 psurface conductance of particleradius of particle
If K(ω) gt 0 then particles move to regions of highest field strength - positive DEP
If K(ω) lt 0 then particles move to regions of lowest field strength - negative DEP
1
Activity 1 - Plotting Re[K(ω)] vs ω for 500 and 200 nm beads
A plot of the Clausius-Mossotti factor versus frequency for 216-nm- (dashed) and 557-nm-diameter (solid) latex particles with a particle permittivity p = 255 and a medium conductivity m = 1 mSm-1 The surface conductance was set at 232 nS for both sizes of particles
Morgan Hywel et al ldquoSeparation of Submicron Bioparticles by Dielectrophoresisrdquo Biophys J July 1999 p 516-525 Vol 77 No 1
Electrode Arrays and Electric Field Analysis
The Scaling Law
V ~ the applied voltage and Le ~the characteristic length of the electrodes
Deposit gold electrodes
Si Substrate
Electrode Fabrication amp Electrode Configuration
Parallel Tip-to-tip electrode array
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Castellated electrode array
N G Green and H Morgan Dielectrophoretic separation of nano-particles
J Phys D Appl Phys 30 (1997)
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Separation Techniques
bull Electrophoresis - migration of charged molecules in an electrical field
bull Electroosmosis - the movement of liquid through a bed of particles by applying an electric field
bull Dielectrophoresis (DEP) - the manipulation of polarizable particles by non-uniform AC fields Non-invasive non-destructive alternating pulses at controllable frequency
Dielectrophoretic Force
bull DEP Force on the particlendash r = radius of particle
ndash εm= permittivity of medium
ndash Re[K(ω)]-real part of the Clausius-Mossotti factor
E - gradient of electric field
23 )](Re[2 EKrF mDEP
Clausius-Mossotti Factor
εm= complex permittivities of the medium
εp = complex permittivities of the particle
σ the conductivity ε the permittivity ω the angular frequency of the applied electric field j=-1 psurface conductance of particleradius of particle
If K(ω) gt 0 then particles move to regions of highest field strength - positive DEP
If K(ω) lt 0 then particles move to regions of lowest field strength - negative DEP
1
Activity 1 - Plotting Re[K(ω)] vs ω for 500 and 200 nm beads
A plot of the Clausius-Mossotti factor versus frequency for 216-nm- (dashed) and 557-nm-diameter (solid) latex particles with a particle permittivity p = 255 and a medium conductivity m = 1 mSm-1 The surface conductance was set at 232 nS for both sizes of particles
Morgan Hywel et al ldquoSeparation of Submicron Bioparticles by Dielectrophoresisrdquo Biophys J July 1999 p 516-525 Vol 77 No 1
Electrode Arrays and Electric Field Analysis
The Scaling Law
V ~ the applied voltage and Le ~the characteristic length of the electrodes
Deposit gold electrodes
Si Substrate
Electrode Fabrication amp Electrode Configuration
Parallel Tip-to-tip electrode array
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Castellated electrode array
N G Green and H Morgan Dielectrophoretic separation of nano-particles
J Phys D Appl Phys 30 (1997)
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Dielectrophoretic Force
bull DEP Force on the particlendash r = radius of particle
ndash εm= permittivity of medium
ndash Re[K(ω)]-real part of the Clausius-Mossotti factor
E - gradient of electric field
23 )](Re[2 EKrF mDEP
Clausius-Mossotti Factor
εm= complex permittivities of the medium
εp = complex permittivities of the particle
σ the conductivity ε the permittivity ω the angular frequency of the applied electric field j=-1 psurface conductance of particleradius of particle
If K(ω) gt 0 then particles move to regions of highest field strength - positive DEP
If K(ω) lt 0 then particles move to regions of lowest field strength - negative DEP
1
Activity 1 - Plotting Re[K(ω)] vs ω for 500 and 200 nm beads
A plot of the Clausius-Mossotti factor versus frequency for 216-nm- (dashed) and 557-nm-diameter (solid) latex particles with a particle permittivity p = 255 and a medium conductivity m = 1 mSm-1 The surface conductance was set at 232 nS for both sizes of particles
Morgan Hywel et al ldquoSeparation of Submicron Bioparticles by Dielectrophoresisrdquo Biophys J July 1999 p 516-525 Vol 77 No 1
Electrode Arrays and Electric Field Analysis
The Scaling Law
V ~ the applied voltage and Le ~the characteristic length of the electrodes
Deposit gold electrodes
Si Substrate
Electrode Fabrication amp Electrode Configuration
Parallel Tip-to-tip electrode array
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Castellated electrode array
N G Green and H Morgan Dielectrophoretic separation of nano-particles
J Phys D Appl Phys 30 (1997)
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Clausius-Mossotti Factor
εm= complex permittivities of the medium
εp = complex permittivities of the particle
σ the conductivity ε the permittivity ω the angular frequency of the applied electric field j=-1 psurface conductance of particleradius of particle
If K(ω) gt 0 then particles move to regions of highest field strength - positive DEP
If K(ω) lt 0 then particles move to regions of lowest field strength - negative DEP
1
Activity 1 - Plotting Re[K(ω)] vs ω for 500 and 200 nm beads
A plot of the Clausius-Mossotti factor versus frequency for 216-nm- (dashed) and 557-nm-diameter (solid) latex particles with a particle permittivity p = 255 and a medium conductivity m = 1 mSm-1 The surface conductance was set at 232 nS for both sizes of particles
Morgan Hywel et al ldquoSeparation of Submicron Bioparticles by Dielectrophoresisrdquo Biophys J July 1999 p 516-525 Vol 77 No 1
Electrode Arrays and Electric Field Analysis
The Scaling Law
V ~ the applied voltage and Le ~the characteristic length of the electrodes
Deposit gold electrodes
Si Substrate
Electrode Fabrication amp Electrode Configuration
Parallel Tip-to-tip electrode array
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Castellated electrode array
N G Green and H Morgan Dielectrophoretic separation of nano-particles
J Phys D Appl Phys 30 (1997)
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Activity 1 - Plotting Re[K(ω)] vs ω for 500 and 200 nm beads
A plot of the Clausius-Mossotti factor versus frequency for 216-nm- (dashed) and 557-nm-diameter (solid) latex particles with a particle permittivity p = 255 and a medium conductivity m = 1 mSm-1 The surface conductance was set at 232 nS for both sizes of particles
Morgan Hywel et al ldquoSeparation of Submicron Bioparticles by Dielectrophoresisrdquo Biophys J July 1999 p 516-525 Vol 77 No 1
Electrode Arrays and Electric Field Analysis
The Scaling Law
V ~ the applied voltage and Le ~the characteristic length of the electrodes
Deposit gold electrodes
Si Substrate
Electrode Fabrication amp Electrode Configuration
Parallel Tip-to-tip electrode array
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Castellated electrode array
N G Green and H Morgan Dielectrophoretic separation of nano-particles
J Phys D Appl Phys 30 (1997)
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Electrode Arrays and Electric Field Analysis
The Scaling Law
V ~ the applied voltage and Le ~the characteristic length of the electrodes
Deposit gold electrodes
Si Substrate
Electrode Fabrication amp Electrode Configuration
Parallel Tip-to-tip electrode array
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Castellated electrode array
N G Green and H Morgan Dielectrophoretic separation of nano-particles
J Phys D Appl Phys 30 (1997)
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Deposit gold electrodes
Si Substrate
Electrode Fabrication amp Electrode Configuration
Parallel Tip-to-tip electrode array
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Castellated electrode array
N G Green and H Morgan Dielectrophoretic separation of nano-particles
J Phys D Appl Phys 30 (1997)
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Parallel Tip-to-tip electrode array
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Castellated electrode array
N G Green and H Morgan Dielectrophoretic separation of nano-particles
J Phys D Appl Phys 30 (1997)
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Castellated electrode array
N G Green and H Morgan Dielectrophoretic separation of nano-particles
J Phys D Appl Phys 30 (1997)
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Polynomial electrode array (1)
N G Green and H Morgan Dielectrophoretic investigations of sub-micrometre latex spheres J Phys D Appl Phys 30 (1997) 2626ndash2633
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Michael Pycraft Hughes AC Electrokinetics Applications for Nanotechnology httpwwwforesightorgConferencesMNT7PapersHughes
Polynomial electrode array (2)
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Stern Model amp Interfacial Effects on Electrode
surface charges
bound ions (Stern layer)
diffuse double layer
Double layer or Stern layer Electro-osmosis
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Combination of DEP and EHD forces
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Applications of DEP
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
100 kHz positive DEP
Chains of beads at the electrodes
1 MHz negative DEP
Beads trapped at the center
Electrode array for DEP
Electric field map
Positive and negative DEPbull Digitized images of 282 nm
latex spheres in a fluorescence microscopes
bull Suspending buffer 10 mM potassium phosphate conductivity =017 Sm
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Complications of negative DEPbull High frequency (MHz) needed to achieve negative DEP
bull Particles are trapped in the electric cage
bull Brownian motion
Dielectric potential well where particles are trapped in negative DEP
Potential barrier preventing particles
from entering the well
E2 map
electrode
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Example of electrode configurations for electric cages
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
DEP applications - 1bull Separation of metallic and semi-conducting nano-tubes (for nano-scale electronics
research and applications)
ndash Suspension of Carbon nano-tubes subjected to a inhomogeneous AC field
ndash Metallic nanotubes (and bundles containing at least one metallic nano-tube dominating the dielectric properties) are attracted at the electrodes
ndash The nano-tubes remaining in the suspension are semi conducting
Suspension drop electrodes
SWNT experimental set-up
R Krupke F Hennrich H Lohneysen M Kappes Universitat Karlsruhe D Science 301 pp 344-347 (2003)
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
DEP applications - 2bull Trapping of human viruses (detection research of viral properties)
ndash 250 nm diameter enveloped human virus and viral capsid of Herpes simplex (HSV-1)
ndash Gold electrodes on glass slides 1 Hz to 20 MHz AC excitation
ndash Stable levitation of a single viral capsid in the potential well
electrodes
virus
envelopeHerpes Simplex Virion (HSV-1) virus and its envelope
M Hughes and H Morgan University of Glasgow UK J of D appl Phys 31 pp 2205-2210 (1998)
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
DEP applications - 3bull Concentration of colloids from solution
ndash Useful eg to collect single parts for nano-machines on the ldquoassembly siterdquo using negative DEP Examples
bull two or more interlocking molecules normally in a highly dilute solution concentrated by DEP into a confined space where they assemble
bull collecting fuel for a nano-machine from solution Self-assembly reaction takes place at the collection point
bull bringing together stacking particles of different types which bind on contact
bull etc
bull Example of manipulation of nano-particles
ndash 14 nm diameter fluorescently labeled latex spheres precipitated from an aqueous solution (=25 mSm-1) by positive (a) and negative (b) DEP
ndash micro spheres and colloidal gold particles fictionalized using antibodies used to construct microscopic biosensors(1)
8 Vpp 2 MHz 10 Vpp 10 MHz
(1)Velev OD Kaler EW In situ assembly of colloidal particles into miniaturized biosensors
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
DEP applications - 4 bull Dielectrophoretic separation and transportation of cells on micro fabricated chips
ndash microchip with a suitable array of electrodes produces controlled transport and switching electric fields
ndash The electric field pattern is switched so that human blood cells are transported from the top of the chip to the left side (see next slide)
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Particle switch with 4-phase signals applied to the electrodes
Transportation chip (bottom) and guide chip (top) separated by 80 m
Fluid chamber comprising a DEP chip
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
DEP applications - 4
J Xu L Wu M Huang W Yang J Cheng X-B Wang AVIVA Bioscences Corp CA amp Dept of Biological Sciences and Biotechnolog Tsinghua University Beijing China
Blood cell
Transport along top channel Three-way switching to left channel
Transport along left channel
1 2 3
Transport electrode
Three-way
switch
White blood cells retained by sinusoidal electrodes human blood
Application of AC voltages caused carbon beads to be collected along electrode edges and polystyrene beads to be levitated
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
DEP applications - 5
bull Dielectrophoretic size-sensitive particle filter for micro-fluidics applications
ndash The dielectrophoretic force and the cross-over frequency from positive to negative DEP depends on the particle radius
ndash At given frequency particles with smaller radius tend to experience positive DEP particle with larger radius experience negative DEP
ndash By proper geometry arrangement of electrodes and operating frequency selection it is possible to trap particles selectively based on their size
J Auerswald HF Knapp Micro Center Central Switzerlandtrapped
free
23 Re2 rmsCMmDEP EfRF
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
DEP applications - 6
DEP of 557 nm diameter latex spheres(a) Negative DEP with polynomial electrode array (b) Negative DEP with castellated electrode array (c) Positive DEP with polynomial electrode array (d) Positive DEP with castellated electrode array
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
DEP applications - 6
(a) Schematic of fluid flow observed in polynomial arrays at high frequencies (b) Schematic of fluid flow observed at low frequencies and low potentials (c) Experimental image (12 Volts peak-to-peak 6 MHz) (d) Experimental image (5 Volts peak-to-peak 3 MHz)
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
DEP applications - 6
Diagrams and experimental images of AC electro-osmosis for two designs of electrodes (a) Schematic diagrams for polynomial electrode arrays (b) Schematic diagrams for castellated electrode arrays (c) Experimental image for polynomial electrode arrays (d) Experimental image for castellated electrode arrays
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
DEP applications - 6
Experimental images of 557 nm diameter latex spheres over three decades of frequency on castellated electrode arrays at an applied potential of 8 Volts peak-to-peak and a solution conductivity of 2 mSm-1
NG Green A Ramos H Morgan J Phys D Appl Phys 33 pp 632-641 (2000)
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
The ExperimentThe Equipment
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Activity 2 Positive DEP
bull Moviesndash posforkavindash posstickavindash possquareavi
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Activity 3 Negative DEP
bull Moviendash negstickavi
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Activity 4 Carbon Nanotube Manipulation
bull Positivendash cntposavi
bull Negativendash negcntavi
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Side view of traveling wave device
bull Buffer ndash 10 mM potassium phosphatebull Conductivity 017 Sm-1bull Latex sphere diameter 557 nmbull 1 Hz to 20 MHz AC bull Negative DEP 5 V p-p 5 MHzbull Positive DEP 5 V p-p 500 kHz
Top view of device design
Y1 = A sin(t) Y2 = A sin(t +2)Y3 = A sin(t + )Y4 = A sin(t +3 2)
Inspired from John Zelena (Mechanical Engineering) ndash Wilkes University NSF Summer Undergraduate Fellowship in Sensor Technologies technical report (2004)
Future Activity Four Electrode Manipulation
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
Acknowledgements
bull Thanks tondash Dr Moldovandash Prof Espinosandash Dr Espinosarsquos graduate students that had to
keep logging us back on to the server when we would crash the computer
