AC electric field enhanced rapid serum immunoassay for Johne’s Disease

Abstract

Early immunoassay is essential at the beginning of human/animal disease diagnosis. Due to limited concentration of antibody and slowly nature diffusion, it takes hours or more time to detect the disease specific antibody in serum using traditional diagnosis methods. A novel approach is proposed to enhance the convection and mass transfer in the micro channel based on AC electroth- ermal effect and dielectrophoresis, improving the antigen-antibody specific binding efficiency greatly, even the antibody in the serum at low concentration level. A platform with interdigited electrode array on silicon wafer and PDMS micro channel is developed for bovine paratuberculosis(Johnes Disease) rapid diagnosis. It only takes 2 minutes to distinguish positive serum from negative ones by measuring the change of electrode/serum interfatial electrical double layer capacitance at real time. Ac electric field enhanced rapid serum immunoassay diagnosis mechanism is presented based on AC electrolthermal and dielectrophoresis theory. Convection and mass transfer is greatly enhanced by AC electric field, leading to a rapid specific binding. The change of disease specific antibody concentration in the micro channel is simulated, showing validity of the novel rapid immunoassay diagnosis method.