Facile synthesis of IrO2/rGO nanocomposites with high peroxidase-like activity for sensitive colorimetric detection of low weight biothiols

In this work, we reported a novel nanozyme synthesized by decorating highly dispersed ultrafine IrO 2 nanoparticles on reduced graphene oxide (rGO) nanosheets via a simple hydrothermal method . The as-prepared IrO 2 /rGO nanocomposites exhibited intrinsic peroxidase-like activity and could catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to produce blue product in the presence of H 2 O 2 . Catalytic kinetic of IrO 2 /rGO nanocomposites followed Michaelis-Menten behavior, exhibiting a higher affinity to TMB than horseradish peroxidase (HRP) enzyme. Catalytic mechanism studies suggested that the peroxidase-like activity of IrO 2 /rGO nanocomposites originated from their ability of electron transfer between substrate and H 2 O 2 . On the basis of high peroxidase-like activity of IrO 2 /rGO nanocomposites, a colorimetric strategy for rapid and sensitive detection of low weight biothiols was developed. The colorimetric detection assays for low weight biothiols showed high selectivity against other amino acids . Therefore, the IrO 2 /rGO nanozyme is expected for promising potential applications in the biosensor, diagnostics and environment.