V2O5-montmorillonite nanocomposites of peroxidase-like activity and their application in the detection of H2O2 and glutathione

In this work, montmorillonite, a traditional layered mineral, the surface of which was modified was further applied in biological detection. Specifically, a novel composite (V2O5-Mt) composed of V2O5 nanoparticles anchored on montmorillonite was synthesized by a simple method. The V2O5-Mt possessed the enhanced peroxidase-like activity, proved by evaluating the catalysis of 3′,3′,5′,5′-tetramethylbenzidine (TMB) oxidized by H2O2, accompanied by a visual change of color. Furthermore, the more the H2O2 content, the deeper the color changed. On the basis of this, a novel colorimetric platform for detecting H2O2 was established with the linear range and the limit of detection was found to be 30 to 400 μM and 4.0 μM, respectively. The peroxidase-like activity of V2O5-Mt is in accord with Michaelis-Menten kinetics. The fluorescent probe experiments verified that the catalytic activity of V2O5-Mt was attributed to the acceleration of electrons transfer among V2O5-Mt, TMB, and H2O2, which was promoted by the vanadium valence state changes between V and IV. The sensing platform was also successfully applied to detect H2O2 in real samples. Furthermore, a colorimetric sensing platform was established to detect glutathione with the linear range and limit of detection to be 0.1–30 μM and LOD = 0.069 μM, respectively.