Immobilizing Antibody with Electropolymerized Staphylococcal Protein A in Micro Amperometric Immunosensor for Detecting Salmonella Typhimurium
A new method based on co-electropolymerizing staphylococcal protein A(SPA) and polypyrrole(PPy) to modify the sensing surface was developed and applied for the detection of Salmonella typhimurium(S.typhi) in a micro amperometric immunosensor,which was an electrochemical system composed of two-electrode system and fabricated based on micro-electro-mechanical systems(MEMS) technology. In the research,the factors influencing the performance of the resulting immunosensor were studied in detail. With visual verification by SEM images,the experiment results demonstrate that this method as a controllable and convenient manipulation can effectively immobilized SPA on the surface of the working electrode for further orientation-controlled immobilization of capture antibodies more rapidly(in 10 min) with less consumption of reagent(10 μL),and enhance the property of the sensor. These all prove the feasibility of the method which was proper to sensing surface modification of the micro immunosensor. The studied immunosensor can detect S.typhi with the concentration of 102 cfu/ml with acceptable specificity and reproducibility. This work is potential to develop a portable,cost-effective and accurate biosensor for real-time sensing of pathogens in food products.