Bioinspired Fabrication of Two-Dimensional Metal–Organic Framework-Based Nanozyme for Sensitive Colorimetric Detection of Glutathione
Yue Zhou, Bo Zheng, Leiming Lang, Guang‐Xiang Liu, Xing‐Hua Xia
Abstract
Inspired by the ultrahigh reactivity of the Fe–N4 active site in natural enzyme horseradish peroxidase (HRP), this work designs and fabricates a two-dimensional (2D) metal–organic framework (MOF)-based nanozyme, 2D Cu-TCPP(Fe) MOFs, involving long-ordered arrangement of the Fe–N4 macrocyclic units. The framework has been constructed by the bridging coordination between Cu(II) ions and the peripheral carboxyl groups of a Fe(III) ion-centered metalloporphyrin TCPPFe. Taking H2O2 and 3,3′,5,5′-tetramethylbenzidine (TMB) as the substrates, the nanozyme shows an excellent activity toward H2O2 decomposition with a Michaelis constant (Km) of 2.67 mM smaller than that of HRP. The hydroxyl radical (·OH)-involved reaction mechanism has been verified experimentally, with the Fe–N4 moieties identified as the active sites. As a proof-of-concept application, the nanozyme-catalyzed TMB + H2O2 system is employed as a colorimetric assay for glutathione detection, which delivers two linear ranges of 0.1–10 and 10–60 μM, with a lower detection limit of 90.8 nM (S/N = 3). In the meantime, the satisfying peroxidase-like (POD-like) activity of 2D Cu-TCPP(Fe) MOFs holds great potential for wider biochemical and biomedical applications.