Highly sensitive electrochemical immunosensor for the simultaneous detection of multiple tumor markers for signal amplification.

A novel sandwich-type electrochemical immunosensor has been fabricated for simultaneous determination of three kinds of tumor markers (TMs). The signal-amplified platform for sensor was assisted by graphene oxide (GO) loaded with Poly(styrene-alt-maleic anhydride) (PSMA). Three TMs of prostate specific antigen (PSA), human a-fetoprotein (AFP) and carbohydrate antigen 125 (CA 125) were employed as model test molecules. This sandwich-type immunoassay could detect the three antigens in differential pulse voltammetry (DPV) scan well at the same time. Under the optimized conditions, the multiplexed immunosensor displayed a splendid linear response in the range of 1.13 pg mL-1 - 113 ng mL-1 for PSA, 0.35 pg mL-1 - 35 ng mL-1 for AFP and 0.025 U mL-1 - 250 U mL-1 for CA 125. The detection limit was 86 fg mL-1, 14 fg mL-1 and 0.0019 U mL-1 for PSA, AFP and CA 125, respectively. This strategy provides a simple and sensitive method for immunoassay for the identification and validation of specific early cancers.