N,N′-di-caboxy methyl perylene diimide (PDI) functionalized CuO nanocomposites with enhanced peroxidase-like activity and their application in visual biosensing of H2O2 and glucose

Abstract

Nanomaterial-based enzyme mimics (nanoenzymes) are a new forefront of chemical research at present. N,N′-Di-carboxy methyl perylene diimide (PDI) functionalized CuO nanobelts with pores (PDI–CuO nanobelts), which were prepared via a facile method and characterized using various analytical techniques, were demonstrated for the first time to possess higher intrinsic peroxidase-like activity towards classical colorimetric substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H₂O₂), compared with that of pure CuO nanobelts without PDI modification. The underlying reaction mechanism was elucidated by catalyzing the decomposition of H₂O₂ and generating hydroxyl radicals (˙OH). The improved catalytic activity of PDI–CuO nanobelts for colorimetric reactions could be ascribed to the synergistic effects of CuO and PDI nanobelts. Moreover, the proposed PDI–CuO biosensor platform exhibited a more sensitive response to H₂O₂ with a low limit of detection (LOD) of 2.38 μM. This convenient sensing platform was further extended to detect glucose in combination with the specificity of glucose oxidase (GOx) for the oxidation of glucose and generation of H₂O₂. The linear range for glucose detection was from 2 μM to 50 μM with a low detection limit of 0.65 μM. Therefore, besides high sensitivity and selectivity, this colorimetric system also holds considerable potential for biological process research.