Single-Probe Sensing Array Based on Au Nanozyme for Simple, Rapid, and Low-Cost Colorimetric Identification of Antioxidants

Abstract

Identification of biological antioxidants is of vital importance because of the essential role of antioxidants in keeping the balance of various diseases. Here, we designed a simple, rapid, and low-cost nanozyme sensing array for colorimetric identification of multiple antioxidants based on Au nanoparticles (Au NPs) synthesized via a facile and green aqueous phase method. In the presence of H₂O₂, Au NPs possessed peroxidase-like catalytic activity and could effectively catalyze the color-less 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized product with comparable enzyme kinetics parameters. The function of the colorimetric sensing array was based on the inhibitory effect of diverse antioxidants on the chromogenic system to varying degrees under different pH conditions, resulting in various “turn-off” colorimetric signal responses. Based on the developed sensing array, four kinds of antioxidants with various concentrations and different proportions of the mixtures were successfully discriminated from each other with the aid of principal component analysis. Moreover, the sensing array showed good performance in differentiating antioxidants in human serum samples, which broaden the analytical application of Au NPs. Compared with the existing sensing array, the single Au NP-based sensing array significantly simplified the sensing element and detection process, opening a new avenue for biological molecule identification in real complex samples.