afm analysis of gallid herpesvirus 1 casey ross mullikin reu faculty mentor: dr. steve tung reu...
TRANSCRIPT
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
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
Virus
• Known as– Gallid Herpesvirus 1– Avian Herpesvirus 1– Infectious
Laryngotracheitis– Chicken Herpes
• Properties– Spherical– 200-400 nm– RNA Virus– 5 Glycoprotein
Subtypes
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