Novel “On–Off” Colorimetric Sensor for Glutathione Based on Peroxidase Activity of Montmorillonite-Loaded TiO₂ Functionalized by Porphyrin Precisely Controlled by Visible Light

Abstract

Well-dispersed nanocomposites based on Ca-montmorillonite decorated by porphyrin-functionalized titanium dioxide (H2TCPP–TiO2–MMT) were synthesized by a facile strategy. H2TCPP–TiO2–MMT was demonstrated to possess the intrinsic peroxidase-like activity and could catalyze 3′,3′,5′,5′-tetramethylbenzidine (TMB) oxidized by H2O2 accompanied with the color change from colorless to blue in a short time under visible light irradiation. The optimum experimental conditions, robustness, as well as Michaelis–Menten kinetics were investigated. The fluorescent probe assay indicated that the good performance of H2TCPP–TiO2–MMT was attributed to the •OH radicals from H2O2 decomposition, which was induced by the electron–hole pairs of H2TCPP–TiO2–MMT generated under visible light irradiation. Based on its peroxidase activity, a convenient colorimetric sensor for detecting glutathione (GSH) was proposed. The detection limit for GSH was 0.057 μM, with the linear detection range of 0.1–20 μM. Notably, besides the enhanced peroxidase-like activity, another merit for this sensor was that the reaction time can be controlled accurately by adjusting irradiation time compared to traditional colorimetric sensors, which would benefit the accuracy in detecting GSH. In addition, results of anti-interference and detecting GSH in human serum assays indicated that the H2TCPP–TiO2–MMT was predicted to be one of the promising materials for fast visual colorimetry.

Novel Heterostructure of a MXene@NiFe-LDH Nanohybrid with Superior Peroxidase-Like Activity for Sensitive Colorimetric Detection of Glutathione

“…Table S3 summarizes the detection methods of GSH with MXene@NiFe-LDH in this study and other nanoenzyme systems. By comparison, we can conclude that the current proposed method for detecting GSH is more sensitive and efficient than the previous reported methods. ,,− In addition, the whole detection process is much shorter than the other studies. ,,− This reveals that the current proposed method has great advantages, for example easy operation and high efficiency. Besides, using colorimetric method, we can easily achieve visual detection by naked eyes, rather than using any expensive or sophisticated instruments, endowing it with absolute advantages compared with other methods …”

Hg2+ Significantly Enhancing the Peroxidase-Like Activity of H2TCPP/ZnS/CoS Nanoperoxidases by Inducing the Formation of Surface-Cation Defects and Application for the Sensitive and Selective Detection of Hg2+ in the Environment

“…420 nm). Under visible light, excited electrons are transferred from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO) of H 2 TCPP . After that, the electrons in the LUMO of H 2 TCPP are transferred to the conduction band (CB) of ZnS and CoS, while the CB of ZnS and CoS is lower than the LUMO of H 2 TCPP. , Thus, photoexcited electrons decompose H 2 O 2 into • OH with strong oxidizing activity, which can easily catalyze the oxidation of TMB.…”

Organic–Inorganic Porphyrinoid Frameworks for Biomolecule Sensing

“…Schematic showing the catalytic mechanism of H 2 TCCP-TiO 2 -MMT nanocomposites. Reprinted with permission from ref . Copyright 2019 American Chemical Society.…”