Sensitive Detection Of Prostate Specific Antigen Based On Copper Ions Doped Ag-Au Nanospheres Labeled Immunosensor

A sandwich-type electrochemical immunosensor was designed for quantitative detection of prostate specific antigen (PSA). Gold-platinum bimetallic functionalized tin oxide graphene (GS-SnO2-Au@Pt) has a large specific surface area, good conductivity and biocompatibility, which was used as the sensing interface to capture PSA coating antibody (Ab(1)). The copper ions doped Ag-Au nanospheres (Cu2+@Ag-Au) was prepared and used as a label of PSA labeling antibody (Ab(2)), which generated high intensive electrochemical redox signal based on the reduction reaction of Cu2+. The L-cysteine was applied as a bridge to connect Au nanoparticles (NPs) and Ag NPs, and to keep the nanosized gap between Au nuclear and Ag shell. This structure not only makes full advantage of space effect to load more Ag NPs but also increases the specific surface area for loaded more Cu2+. The proposed immunosensor with a wide range (10 pg mL(-1) to 100 ng mL(-1)) and a low detection limit (3.84 pg mL(-1)) shows excellent performance in the detection of PSA. The results indicate that proposed immunosensor provides a promising application for the quantitative detection of biomolecules in serum samples. (c) 2019 The Electrochemical Society.