Electrochemical immunosensor detection of tumor markers based on a GO composite nanoprobe for signal amplification

A novel strategy based on nanoprobes for signal amplification was introduced in an electrochemical immunoassay platform. The nanoprobes based on poly(2-hydroxyethyl methacrylate)-r-poly(acrylic acid) (PHEMA-r-PAA) and graphene oxide (GO) have the effect of double signal amplification. The resulting sandwich-type electrochemical immunosensor was able to detect the tumor marker alpha fetal protein (AFP) with high sensitivity and high selectivity. A good linear relationship could be observed in the AFP concentration range of 3.5 pg mL−1 to 35 ng mL−1 (R2 = 0.9898), and the minimum detection limit was 0.106 pg mL−1. In addition, the electrochemical immunosensor exhibited good stability and could be applied to AFP detection in clinical serum.