Fe,Cu/His bimetallic nanozyme with enhanced peroxidase-like activity for colorimetric detection of glucose

Abstract

Herein, a novel bimetallic (Fe,Cu/His) nanozyme with high peroxidase (POD)-like activity for colorimetric assaying of glucose was designed. Assisted by glucose oxidase (GOx), glucose could be specifically converted into H₂O₂ for oxidizing chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) catalyzed by Fe,Cu/His to generate blue oxTMB with absorption at 654 nm. Specifically, Fe,Cu/His exhibits excellent POD-like activity due to ascorbic acid with reducing properties to ensure the formation of binary-valence metal pairs (Fe³⁺/Fe²⁺ and Cu²⁺/Cu⁺), thus enhancing electron transfer during the catalytic process. Based on the cascade reaction of GOx and the Fe,Cu/His nanozyme, a sensitive colorimetric assaying platform for glucose detection was constructed with a good linear range of 5–1000 µM and a calculated limit of detection of 1.44 µM. This proposed method was applied to assay glucose in tobacco samples sensitively and accurately.