AC electrokinetics assisted impedance biosensors for rapid bacteria detection

Early detection of living bacteria attracts a lot of attention in infection diseases applications, especially at low concentration. Nowadays, the detection of specific bacteria faces challenges including enhancement of trapping efficiency, and increase of sensor sensitivity and specificity. In this study, we improved the trapping efficiency and increased sensor sensitivity and specificity by using AC electrokinetics and selective modification of antibody on gold electrode in a new structure of gold electrode design. COMSOL simulations of AC electrokinetics include dielectrophoresis (DEP), and AC electroosmosis (ACEO) were performed on different electrode designs and bias configurations. The simulation results were consistent with the fluorescence observations showing that the bacteria were trapping selectively on gold electrodes. The impedance measurements for Vibrio parahaemolyticus (Vp) detection at 105 cfu/ml with AC elctrokinetics showed a nearly 90% change in normalized impedance change (NIC).