Synergetic PtNP@Co3O4 hollow nanopolyhedrals as peroxidase-like nanozymes for the dual-channel homogeneous biosensing of prostate-specific antigen

In this paper, novel synergetic PtNP@Co 3 O 4 hollow nanopolyhedrals with peroxidase-like activities are designed and prepared, which can be used as electrochemical and colorimetric signal labels for the enzyme-free dual-channel homogeneous sensing of prostate-specific antigen. When prostate-specific antigens are present, the aptamer-modified PtNP@Co 3 O 4 hollow nanopolyhedrals and magnetic beads form sandwich structures, which have excellent peroxidase-like activities, because of the synergetic effect of PtNP@Co 3 O 4 hollow nanopolyhedrals. The sandwich structures can be separated from the mixture by the magnetic effect of the magnetic beads and catalyze the redox reactions between H 2 O 2 and TMB, generating quantitative electrochemical and colorimetric responses in homogeneous solution simultaneously. Under the optimized conditions, the linear range of both electrochemical (0.01 to 10 ng/ml) and colorimetric (0.01–15 ng/ml) channels can satisfy the demand of prostate-specific antigen detection in clinic (4 ng/ml), and the electrochemical and colorimetric channels have a low detection limit of 0.0079 ng/ml and 0.01 ng/ml respectively without using natural enzymes. The strategy by using synergetic PtNP@Co 3 O 4 hollow nanopolyhedrals as signal probes provides a promising scheme for developing simple, rapid, reliable, and ultrasensitive dual-channel homogeneous biosensors, which has a great potential as a powerful tool in prostate cancer diagnosis. Graphical abstract