Optical Biosensors

Joel Kindt

Lauren Netherton

Acknowledgements

Dr. Kevin Lear

Dr. Dave Kisker

Weina Wang

Hailey Cutler

1

 

Lauren Netherton

• Motivation and Introduction

• Prior Research

• How Optical Biosensors Work

2

 

3Courtesy of Kian Behbakht of UC Denver

 

Prior Research

Senior Design Team 2007-2008

4

 

Pipe Organ Analogy

• Place fruit in organ pipe

• Changes pitch based on:– Size– Shape

http://lib.colostate.edu/archives/phelps/

5

6

Optical Detection & RF Switch

Circuit Spectrometer

HealthyCancerous!

Courtesy of Weina Wang

Trapping Requirements

• Lower voltages– Trap at

slower velocity

• Higher voltages– Trap at

higher velocity

7

 

Dielectrophoretic Force

• Use of electromagnetics• Non-uniform electric field

– Polarizes molecules within cell– Induces DEP force to hold cell in trap

Electric field

8

December 2007 Senior Design Presentation

3 22 Re[ ]DEP mF r K E

Polarization factor (K factor):* *

* *2p m

p m

K

* j

Complex permittivity of particle/suspending medium:

Dielectrophoretic Force

9Courtesy of Weina Wang

 

Joel Kindt

• Electrostatic Modeling

• Experimental Data

• Budget

• Conclusions and Future Work

10

 

Electrodes on Chip

11

 

Electrostatic Modeling

12

 

3 22 Re[ ]DEP mF r K E

DEP ForceE-Field

13

Positive and Negative DEP

• Mammalian white blood cell

• σm = 0.1 S/m (~ water)

• σm = 1.5 S/m (~ PBS)

3 22 Re[ ]DEP mF r K E

Joel Voldman, “Electrical Forces For Microscale Cell Manipulation”, Annu. Rev. Biomed. Eng. 2006. 8:425-54

14

Polarization factor (K factor):* *

* *2p m

p m

K

K > 0: Positive DEP K < 0: Negative DEP

* j

,

 

Experimental Setup

15

 

Impedance of Channel

Voltage Divider

http://en.wikipedia.org/wiki/Voltage_divider16

 

more heat dissipated at lower impedance

17

Impedance of Channel

 

Budget

Materials 1st semesterbudget

1st semesteractual

2nd semesterbudget

Syringes $15 $0 $15

Glass $75 $0 $0

Nanoports $0 $0 $60

Nanotubing $0 $0 $25

Flexible mirror $10 $0 $0

Total $100 $0 $100

18

 

• Know trapping requirements for various fluid velocities

• Possible to model cell trap through simulations– Electric field

– DEP force

• The fluid properties can affect results– K factor

– Impedance of channel19

Conclusions

 

• Design better cell trap through simulations

• Further understand spectra– Cancerous vs. non-cancerous cells

– Different types of cancer

• Save Rover!

20

Future Work