Electrical measurements were made by
using lock-in detection with a modulation frequency chosen as
a prime number between 17 and 79 Hz, inclusive. Measurements
were independent of frequency within this range. The modulation
amplitude was 30 mV and the dc source-drain potential was
zero to avoid electrochemical reactions. Conductance vs. time
data were recorded while buffer solutions, or different virus
solutions, flowed through the microfluidic channel. Viral sensing
experiments were performed in the microfluidic channel under
a flow rate of 0.15 mlhr in 10 M phosphate buffer solution
containing 10 M KCl at pH 6.0.