Nonenzymatic immunosensor for detection of carbohydrate antigen 15-3 based on hierarchical nanoporous PtFe alloy

Bimetallic hierarchical nanostructures have attracted increasing attention for biosensing applications due to their higher electrocatalytic activity and better biocompatibility. In this work, we developed a novel sandwich-type nonenzymatic electrochemical immunosensor for cancer biomarker carbohydrate antigen 15-3 (CA15-3). Hierarchical nanoporous PtFe alloys were used as carriers of the signaling antibody anti-CA15-3 in order to achieve an signal amplification. The immunosensor is constructed by using a graphene as platform and using mesoporous PtFe alloy as labels. The electrochemical signal of the immunosensor was based on the high-electrocatalytic activity of PtFe alloy for the electro-oxidation of H2O2. Under optimal conditions, this method could detect CA15-3 ranging from 0.002 to 40 U/mL with a low detection limit of 3 × 10(-4)U/mL. This immunosensor showed good accuracy, stability and fabrication reproducibility. The hierarchical nanoporous metal materials-based immunoassay provides a promising ultrasensitive immunoassay approach for clinical applications.