Multiplexed label-free electrochemical immunosensor for breast cancer precision medicine

A novel multiplexed label-free electrochemical immunosensor was fabricated using graphene/methylene blue-chitosan/antibody and bovine serum albumin on indium tin oxide glass electrode for the simultaneous determination of three types of tumor markers including carcinoembryonic antigen (CEA), cancer antigens 153 (CA153), and cancer antigen 125 (CA125). Cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy were employed to monitor each fabrication step. Under the optimized experiment conditions, the immunosensor exhibited good reproducibility and selectivity with linear ranges of 0.10-1.00 pg mL^-1 and 1.00-100.00 pg mL^-1 for CEA, 0.10-2.50 mU mL^-1 and 2.50-100.00 mU mL^-1 for CA153, 0.10-2.50 mU mL^-1 and 2.50-100.00 mU mL^-1 for CA125, a detection limit of 0.04 pg mL^-1 for CEA, 0.04 mU mL^-1 for CA153, and 0.04 mU mL^-1 for CA125. This electrochemical immunosensor was successfully applied to detect three tumor markers in blood serum samples with good recoveries. The reliability of the electrochemical immunosensor to detect three tumor markers in blood serum samples was in good agreement (P > 0.05) with that of the enzyme-linked fluorescent assay method.