Dielectric Biosensor for E. Coli Detection with DC Bias

This study presents a novel approach for detecting E. coli using dielectric properties enhanced by DC bias. Traditional methods for detecting bacteria often require extensive sample preparation and are hindered by the composition of the solutes in complex liquid backgrounds, and this proposed method overcomes these challenges by utilizing dielectric measurement with DC bias. Aluminum rod electrodes and planar stainless-steel electrodes connected to an impedance analyzer were used to measure the capacitance of liquid samples containing E. coli across a frequency spectrum from 40 Hz to 100 M Hz. Results indicated that the presence of E. coli significantly reduced the change in capacitance when DC bias was applied and removed, suggesting that DC bias is an effective stimulus for E. coli detection in various liquids. Further analysis indicated that the effects were predominantly from the electric double-layer region. This technique effectively leverages the intrinsic properties of bacterial liquid and their response to specific stimuli, which may improve the robustness and accuracy of bacteria detection in complex environments.