A novel sandwich-type electrochemical immunosensor for PSA detection based on PtCu bimetallic hybrid (2D/2D)...

In this work, a sensitive sandwich-type electrochemical immunosensor was designed for the quantitative detection of prostate-specific antigen (PSA) by amperometric i-t. The Au loaded on thionine functionalized graphene oxide (Au@Th/GO) was used as a platform to immobilize primary antibodies (Ab₁) and accelerate the electron transfer on the electrode interface. PtCu bimetallic hybrid were loaded on 2D/2D reduced graphene oxide/graphitic carbon nitride (PtCu@rGO/g-C₃N₄) with large surface area and biocompatibility, which were employed as labels for combining secondary antibodies (Ab₂) and amplifying signals to improve the sensitivity of the designed immunosensor which attributes to its good activity for the reduction of hydrogen peroxide (H₂O₂). Under optimal conditions, the designed immunosensor exhibited a linear concentration range from 50fg/mL to 40ng/mL, with a low detection limit of 16.6fg/mL (S/N=3) for PSA. Additionally, the designed immunosensor showed acceptable selectivity, reproducibility and stability. The satisfactory results in analyze human serum samples indicated potential application promising in clinical monitoring of tumor markers.