Selective detection of glutathione by flower-like NiV2O6 with only peroxidase-like activity at neutral pH

In view of the broad application prospect of peroxidase-like nanozymes in biomedical analysis, it is of great significance to eliminate the interference of their oxidase-like activity and enable them to work under neutral conditions. Herein, flower-like NiV2O6 was synthesized and their enzyme-mimicking activity was investigated. Through the regulation of pH, NiV2O6 nanozyme showed only peroxidase-like activity but not oxidase-like activity under neutral conditions, which could catalyze the oxidation of colorless 3,3 ',5,5 '-tetramethylbenzidine into its blue product in the presence of H2O2. Furthermore, based on the competitive effect of glutathione (GSH) on the catalytic activity of nanozymes, a semi-quantitative/quantitative colorimetric assay was established for GSH detection by using peroxidase-like NiV2O6. The assay exhibited a good linear relationship in GSH concentration ranging from 3-100 mu mol L-1, with a detection limit of 0.89 mu mol L-1. Moreover, in the presence of formaldehyde as masking agent, this method showed satisfactory specificity for GSH under the interference of a variety of interfering substances and even biothiols. Concerning the practical application, the system was applied to monitor GSH level in fetal bovine serum, human serum and SiHa cells. Satisfyingly, the obtained results were consistent well with those of Ultra performance liquid chromatography (UPLC) and assay kit, indicating the constructed assay has great potential in clinical application.

Automated summary

In this study, flower-like NiV2O6 nanozyme with peroxidase-like activity under neutral conditions was successfully synthesized and applied for the detection of glutathione (GSH). The method showed good sensitivity and specificity, with a linear relationship in GSH concentration and satisfactory performance in detecting GSH in various samples. The constructed assay holds great potential for clinical application, as demonstrated by consistent results with UPLC and assay kit.