Characterization of nanozyme kinetics for highly sensitive detection

Abstract

Nanozymes have been widely used as enzyme substitutes. Based on a comprehensive literature survey of 261 publications, we report the significant differences in the Michaelis–Menten constants (K_m) between peroxidase-mimicking nanozymes and horseradish peroxidase (HRP). Further, these differences were not considered in more than 60% of the publications for analytical developments. As a result, nanozymes’ catalytic activity is limited, resulting in a potentially higher limit of detection (LOD). We used a peroxidase-mimicking Au@Pt nanozyme, which has K_m for TMB comparable with HRP and three orders of magnitude higher K_m for H₂O₂. Using the Au@Pt nanozyme as a label for immunoassays, non-optimized nanozyme substrate concentrations led to 30 times higher LOD compared to optimized conditions. The results confirm the necessity of measuring nanozymes’ kinetic parameters and the corresponding adjustment of substrate concentrations for highly sensitive detection.