Mixed-Valence V2O5-(Ce3+/Ce4+) Metal-Organic-Framework Nanorods for the Colorimetric and Fluorometric Detection of Glutathione

Emerging metal-organic framework (MOF)-based nanomaterialssuch as nanozymes have attracted interest and been applied in thedetection of biomolecules like glutathione (GSH). It is still difficultto distinguish GSH from cysteine (Cys) and ascorbic acid (AA) becausemost antioxidants behave similarly. However, the appropriate catalyticactivity, high surface area, etc., of MOF-based nanozymes can allowentry into molecular substrates, analytes, and complete contact withactive nanozymes sites. Then, in this study, the colorimetric andfluorometric detection of GSH based on oxidase mimetic activity wasinvestigated using the mixed-valence state V2O5-(Ce3+/Ce4+)-MOF nanozyme. This sensor demonstrateda suitable linear analytical response in the area of 0.1-75and 0.1-40 & mu;M with a detection limit of 0.048 and 0.06 & mu;M for colorimetric and fluorometric methods, respectively.It is determined that vanadium should direct contact with the GSHmolecules to trigger its activation effect of glutathione-peroxidase.In addition, it could help the preconcentration of GSH on the catalyst'ssurface. When the surface states of the (Ce3+/Ce4+)-MOF covered by the generated GSSG are on the catalyst surface.Therefore, it strongly inhibits the oxidation of tetramethylbenzidine(TMB) by the oxidase-like activity of the catalyst. Therefore, itstrongly inhibits the oxidation of TMB by the oxidase-like activityof the catalyst. This study's strategy of using nanozymes withoxidase and glutathione-peroxidase-like activity to design sensorswill provide a unique pathway for improving the efficiency of MOF-nanozyme-basedsensors.