Emerging metal–organic framework (MOF)-based nanomaterials
such as nanozymes have attracted interest and been applied in the
detection of biomolecules like glutathione (GSH). It is still difficult
to distinguish GSH from cysteine (Cys) and ascorbic acid (AA) because
most antioxidants behave similarly. However, the appropriate catalytic
activity, high surface area, etc., of MOF-based nanozymes can allow
entry into molecular substrates, analytes, and complete contact with
active nanozymes sites. Then, in this study, the colorimetric and
fluorometric detection of GSH based on oxidase mimetic activity was
investigated using the mixed-valence state V2O5-(Ce3+/Ce4+)-MOF nanozyme. This sensor demonstrated
a suitable linear analytical response in the area of 0.1–75
and 0.1–40 μM with a detection limit of 0.048 and 0.06
μM for colorimetric and fluorometric methods, respectively.
It is determined that vanadium should direct contact with the GSH
molecules to trigger its activation effect of glutathione-peroxidase.
In addition, it could help the preconcentration of GSH on the catalyst’s
surface. 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, it
strongly inhibits the oxidation of TMB by the oxidase-like activity
of the catalyst. This study’s strategy of using nanozymes with
oxidase and glutathione-peroxidase-like activity to design sensors
will provide a unique pathway for improving the efficiency of MOF-nanozyme-based
sensors.