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

• A novel and sensitive nonenzymatic sandwich-type electrochemical immunosensor for the detection of CA15-3 is developed.
• The hierarchical nanoporous PtFe as labels there is no enzyme in and PtFe was used to fix the Ab2.
• The reagentless detection process based on the changes of direct electrochemical signals of PtFe-labeled antibodies greatly simplifies the manipulation.
• The proposed method showed excellent performance for detection of CA15-3 with wide linear ranges and low detection limits.

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.