DC and AC conductivity of silicon nanofilaments upon bacterial introduction

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DC and AC conductivity of silicon nanofilaments
upon bacterial introduction.
Gusev Dmitii Vladimirovich
1st year master student of MSU named after M.V. Lomonosov
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Table of Contents
1. Introduction
2. Specimens used
3. Bacteria, methods of obtaining
them
4. Methods of experimentation
5. Results obtained
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3.

Введение
Number of listeriosis cases by fatality
and associated case fatality rate,
England and Wales, 1990-2009.
P. Mook and et al., Epidemiology & Infection, 2011, 709
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4.

Al
Al
Samples
C - Si
1. Large specific surface area.
2. Greater sensitivity to
environmental changes.
3. Possibility to control the
process of SiNWs growth.
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5.

Bacteria used
A non-pathogenic strain of the
intracellular bacterium Listeria
monocytogenes was chosen for the
work.
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6.

Conducting the
experiment
-
Applying a drop of distilled water with a
certain concentration of bacteria to the
sample
-
Manual measurement of VAC from -10V
to 10V in 1V increments.
-
Al
Al
Sample measurement with frequencies
from 1Hz to 13MHz. The bias voltage is
6V.
-
concentrations with values an order of
magnitude higher than the previous
measurements.
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C - Si
Repeat the experiment with new
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Measurement results
-ImZ (106 Ом)
2
1
Вода
|]R = 300 кОм ''| C = 0.2 пФ
105 КОЕ/мл | R = 220 кОм '| C = 0.15 пФ
106 КОЕ/мл | R = 38 кОм ' | C = 0.17 пФ
107 КОЕ/мл | R = 27 кОм '| C = 1.8 пФ
0
0
2
4
6
8
ReZ (105 Ом)
Nyquist plot of impedance
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Equivalent scheme

8.

Dependence of conductivity on bacterial concentration at direct and alternating
currents
- Alternating current
- Direct current
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Dependence of the sensory response of the sample on the concentration of bacteria
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Conclusions:
• It is shown that arrays of silicon nanofilaments can be used to detect Listeria bacteria on both DC and
AC.
• It was found that the introduction of Listeria bacteria significantly changes the resistance of the resistor and
slightly changes the capacitance of the capacitor included in the equivalent circuit.
• It was shown that the addition of Listeria bacteria in distilled water leads to a significant change in the
conductivity of silicon nanofilaments. It was possible to determine a concentration of at least 105 CFU/ml.
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Thank you for your attention!
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