Reduction of incubation time and enhancement of analyte adhesion uniformity of impedance biosensors using microvibration method

Electrochemical impedance spectroscopy (EIS) analysis can detect an analyte with high sensitivity in short time. The self-assembled monolayer (SAM) technique is usually used for attaching analytes to a transducer. In general, the relatively time-consuming incubation time and the non-uniform immobilization of an analyte on the sensing electrode are the commonly encountered problems. This study proposes a simple microvibration method based on Bernoulli's theory for improving incubation time and enhancing the adhesion uniformity of the analyte. The detection of the group-2 allergen Der p2 demonstrates that a suitable applied frequency at a fixed amplitude can considerably reduce the sample preparation time and improve the adhesion and adhesive uniformity of the analyte. It is also found that compared to the conventional dipping method the microvibration method can give a relatively large detection range, provide a relatively better detection linearity, and result in a standard detection curve with a relatively large slope so that the sensitivity of the sensor can be increased and the detection error due to measurement variations can be reduced. The proposed scheme can be further applied to other detection methods that use surface-bound reactions for analyte immobilization.