Synthesis of a Zn-MOF fluorescent material for sensitive detection of biothiols via an inner filter effect with MnO2 nanosheets

Abstract

In this study, zinc ions were employed as the central metal, while 4,4′,4′′-nitrilotribenzoic acid (H₃NTB) served as the fluorescent organic ligand. Through a single-step solvothermal approach, a novel Zn-based metal–organic framework (Zn-MOF) fluorescent material was successfully synthesized. The Zn-MOFs exhibit a cubic morphology, outstanding fluorescence properties, excellent water dispersibility, and robust resistance to high temperature and strong alkaline conditions. Additionally, MnO₂ nanosheets (NSs) were effectively exfoliated from MnO₂ particles using ultrasonic treatment. These MnO₂ NSs possess a broad UV-Vis absorption band that overlaps with the fluorescence spectra of Zn-MOFs. Leveraging the inner filter effect (IFE) between MnO₂ and Zn-MOFs, a Zn-MOF-based fluorescence bioassay technique was developed for the detection of biothiols. The results demonstrate that this Zn-MOF-based fluorescence detection platform exhibits a remarkable sensitivity towards biothiols, achieving a detection limit of 0.067 μM, surpassing that of other reported MnO₂-based detection methods. Furthermore, this detection platform has been successfully applied to the quantitation of glutathione (GSH) in human serum, highlighting its potential for highly sensitive and specific detection of biothiols.