AFM Analysis of Gallid Herpesvirus 1

Casey Ross MullikinREU Faculty Mentor: Dr. Steve Tung

REU Graduate Mentor: Brock Schulte

Objective

• Utilize Atomic Force Microscopy to measure electrical properties of Gallid Herpesvirus 1 (Chicken Herpes)

• Use Viral electrical properties as a detection scheme and identification tool

AFM Schematic

http://upload.wikimedia.org/wikipedia/commons/7/7c/Atomic_force_microscope_block_diagram.svg

Equipment

Agilent 5500 AFM

Scanner

Nose Cone

Cantilever Tip

• Type Used– Contact– Surf– 0.2 N/m – 13 kHz

• Dimensions– Length: 450 μm– Width: 50 μm– Thickness: 2 μm

• Materials– Si– Cr/Pt

Herpesvirus Diagram

http://www.biografix.de/biografix/english/images/2/p_2b2a.jpg

Virus

• Known as– Gallid Herpesvirus 1– Avian Herpesvirus 1– Infectious

Laryngotracheitis– Chicken Herpes

• Properties– Spherical– 200-400 nm– RNA Virus– 5 Glycoprotein

Subtypes

Scans

Beads Virus

Impedance• Like resistance

• Measurement of opposition to a sinusoidal current

• Imaginary number in the form: Z=R+jX

• Reactance is a dielectric property of the substance

– If X>0 it is considered to be Inductive

– If X<0 it is considered to be Capacitive

• Absolute Impedance (Z) and Phase Angle (θ) were Measured

Impedance Analyzer

Impedance ValuesFrequency (Hz) ITO (Ω) Bead (Ω) Virus (Ω) Buffer (Ω) %Difference

100000 55780.8364235.83 67880.56 63833.33 5.37

150000 37740.8342807.50 44905.56 42436.67 4.67

200000 28532.5032364.17 33467.78 32898.89 3.30

250000 22622.5026210.00 26744.44 25721.11 2.00

300000 18939.1721940.00 20172.22 18837.78 8.76

350000 16356.6718953.33 16358.89 15126.11 15.86

400000 14292.5016544.17 13036.22 11956.83 26.91

450000 12696.6714786.67 12822.22 12365.06 15.32

500000 11904.1713920.83 14034.22 14154.00 0.81

550000 11330.0013340.83 13799.78 13801.00 3.33

600000 11124.1713069.17 13221.44 12896.78 1.15

650000 11177.6713037.50 12581.89 11702.33 3.62

7.59

100000 120000 140000 160000 180000 200000 220000 24000010000.00

20000.00

30000.00

40000.00

50000.00

60000.00

70000.00

80000.00

Impedance vs. Frequency

ITO Impedance

Bead Impedance

Virus Impedance

Buffer Impedance

Frequency (Hz)

Imp

ed

an

ce

(O

hm

s)

Conclusions

• The overall Dielectric Constant of the virus was determined to be approximately 2.4

• This value should be unique to this virus and thus allow for its identification via an infected sample analysis.

References

• *1 Research Solutions & Resources LLC.http://www.consultrsr.com/resources/eis/cpe1.htm

• *2 Comparison of Electrical Properties of Viruses Studied by AC Capacitance Scanning Probe Microscopy.Robert I. MacCuspie, Nurxat Nuraje, Sang-Yup Lee, Anne Runge, and

Hiroshi Matsui

• *3 ZView Download. http://www.scribner.com/index.php?option=com_content&task=view&id=36&Itemid=41

• *4 Human Herpes Virus 3. www.ncbi.nlm.nih.gov/.../00.031.1.01.001.htm& http://web.uct.ac.za/depts/mmi/stannard/herpes.html

Questions?