RESUMO
A facile and general strategy has been employed to develop highly-active nanozyme for immunoassay purposes. The hollow nanostructure of the Co3O4 nanocages (NCs) was anchoring the platinum nanoparticles (PtNPs) enclosed by the exposed oxides framework nd formed PtNPs@Co3O4 NCs. The embodiment of PtNPs was considered an ideal hybrid nanozyme that efficiently catalyzed the oxidation of the substrate molecules with enhanced activity. The PtNPs@Co3O4 NCs were revisited and repurposed on showing its nanozyme's activity with optimization done for the immunoassay platform. The embodiment of 32.44% Pt in the hollow nanostructures demonstrated the highest signal-to-noise responses in the immunoassay. In addition, the stepwise analysis highlighted the enhancement factor of the nanocages' catalytic mechanism. Based on their catalytic activity, these nanocages have been demonstrated to enable sub-femtogram level biosensing of norovirus-like particles (NoV-LPs) with highly selective signals in the capture-detect immunoassay format. The detection limit of the prepared immunoassay achieved 33.52 viral NoV copies/mL of the detection limit, which is 321-folds lower magnitude of the commercial ELISA. This nanocage's enhanced synergic catalytic properties could have great potential applications, including catalysis, biological labeling, and bioassays.