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@Co3O4 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@Co3O4 hollow nanopolyhedrals and magnetic beads form sandwich structures, which have excellent peroxidase-like activities, because of the synergetic effect of PtNP@Co3O4 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 H2O2 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@Co3O4 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.