H. pylori is responsible for several stomach-related diseases including gastric cancer. The main virulence factor responsible for its establishment in human gastric cells is known as CagA. Therefore, in this study, we have fabricated a highly sensitive MIP-based electrochemical biosensor for the detection of CagA. For this, an rGO and gold-coated, screen-printed electrode sensing platform was designed to provide a surface for the immobilization of a CagA-specific, molecularly imprinted polymer; then it was characterized electrochemically. Interestingly, molecular dynamics simulations were studied to optimize the MIP prepolymerization system, resulting in a well-matched, optimized molar ratio within the experiment. A low binding energy upon template removal indicates the capability of MIP to recognize the CagA antigen through a strong binding affinity. Under the optimized electrochemical experimental conditions, the fabricated CagA-MIP/Au/rGO@SPE sensor exhibited high sensitivity (0.275 µA ng-1 mL-1) and a very low limit of detection (0.05 ng mL-1) in a linear range of 0.05-50 ng mL-1. The influence of other possible interferents in analytical response has also been observed with the successful determination of the CagA antigen.
Keywords: CagA; H. pylori; biosensors; electrochemical; molecular dynamics simulations; molecularly imprinted polymers.