experiment, we test for No pLDH and 1nM groups (which is the detection
limit) during experiment. For all experiments performed throughout the
development of the present device, no actual saliva samples, infected
or not, were used. Instead, pLDH-containing “samples” are formulated
by diluting stock pLDH to desired concentrations with PBS. Potassium
ferricyanide is included in the solution at a concentration of 0.5 mM.
These formulated samples are kept at 2 mL, which is more than
sufficient to cover the IDA wheatstone. The result is shown in the
figure on the right.
As showing in the figure, x-axis is frequency and y-axis is voltage
output under different frequency. The result shows that under high
frequency ( frequency range from 100 kHz to 5 MHz), the change of pLDH
concentration will lead to a linear change of voltage output of the
electrode. It could also prove that the capacitance change is linear
to pLDH concentration.