PdPtRu trimetallic nanozymes and application to electrochemical immunosensor for sensitive SARS-COV-2 antigen detection

Herein, a ternary PdPtRu nanodendrite as novel trimetallic nanozyme was reported, which possessed excellent peroxidase-like activity as well as electro-catalytic activity on account of the synergistic effect between the three metals. Based on the excellent electro-catalytic activity of trimetallic PdPtRu nanozyme toward the reduction of H 2 O 2 , the trimetallic nanozyme was applied to construct a brief electrochemical immunosensor for SARS-COV-2 antigen detection. Concretely, trimetallic PdPtRu nanodendrite was used to modify electrode surface, which not only generated high reduction current of H 2 O 2 for signal amplification, but also provided massive active sites for capture antibody (Ab 1 ) immobilization to construct immunosensor. In the presence of target SARS-COV-2 antigen, SiO 2 nanosphere labeled detection antibody (Ab 2 ) composites were introduced on the electrode surface according sandwich immuno-reaction. Due to the inhibitory effect of SiO 2 nanosphere on the current signal, the current signal was decreased with the increasing target SARS-COV-2 antigen concentration. As a result, the proposed electrochemical immunosensor presented sensitive detection of SARS-COV-2 antigen with linear range from 1.0 pg/mL to 1.0 μg/mL and limit of detection down to 51.74 fg/mL. The proposed immunosensor provide a brief but sensitive antigen detection tool for rapid diagnosis of COVID-19.