2-Methylimidazole-Regulated MIL-88B(Fe) with Enhanced Peroxidase-Like Activity for Colorimetric Glucose Sensing

Abstract MOF-based nanozymes are promising for colorimetric biosensing but are often limited by rigid coordination environments and poor active-site accessibility. Here, a 2-methylimidazole-regulated MIL-88B(Fe) nanozyme (2-MIM@MIL-88B) was prepared via an in situ coordination-competition strategy. Compared with pristine MIL-88B(Fe), 2-MIM@MIL-88B retained a spindle-like morphology but showed reduced crystallinity, nitrogen-containing species, pore-texture reorganization, and local Fe-site electronic modulation with increased defect-related centers. These changes correlated with enhanced peroxidase-like activity in the TMB-H2O2 system, despite a reduced BET surface area. In a glucose oxidase-coupled colorimetric assay, 2-MIM@MIL-88B enabled glucose detection over 0.015–0.5 mM with a detection limit of 1.7 µM.