Chitosan-Coated MIL-۵۳(Fe) Nanocomposite as a Peroxidase/Oxidase Mimic: A Highly Sensitive Biosensor for the Colorimetric Detection of Hydrogen Peroxide

The iron-based metal-organic framework (MOF) MIL-۵۳(Fe) was successfully functionalized with chitosan through a simple and efficient post-synthetic strategy. This facile modification significantly enhances its catalytic properties, yielding a multifunctional nanocomposite that mimics both peroxidase and oxidase enzymatic activities. The chitosan-coated MIL-۵۳(Fe), an inexpensive and biocompatible material, exhibits superior peroxidase-mimetic catalytic activity compared to its unmodified counterpart, enabling highly sensitive colorimetric biosensing. Upon interaction with hydrogen peroxide (H۲O۲), the nanocomposite facilitates the catalytic oxidation of ۳,۳',۵,۵'-tetramethylbenzidine (TMB), producing a deep blue solution with distinct UV-vis absorption peaks at ۳۶۹ and ۶۵۲ nm. This system demonstrates an exceptional sensitivity, achieving an unprecedented detection limit of ۰.۰۰۳ μM several orders of magnitude lower than existing methods making it one of the most effective platforms for rapid and precise H۲O۲ detection. Furthermore, our optimized catalytic conditions (۴۰ °C, pH ۴.۰, ۱۰ minutes, catalyst concentration: ۰.۱۱ mg mL⁻¹) underscore the remarkable efficiency of our MOF-based peroxidase mimic. Notably, both peroxidase and oxidase activities are seamlessly executed under identical reaction conditions, simplifying multi-step enzymatic processes and eliminating the need for separate optimization protocols. This unique feature enhances overall efficiency while significantly reducing operational costs. The intrinsic rapid catalytic kinetics, reflected in the high Vmax values of ۱۴۷.۷۷×۱۰⁻⁸ Ms⁻¹ for H۲O۲ and ۵۳.۱۱×۱۰⁻⁸ Ms⁻¹ for TMB, further reinforce the system's viability for real-time sensing applications. By integrating high sensitivity, operational simplicity, and cost-effectiveness, our functionalized MIL-۵۳(Fe) nanocomposite presents a groundbreaking advancement in MOF-based biomimetic catalysis.

کلیدواژه ها:

MIL-۵۳(Fe) ، Nanozyme ، Peroxidase Mimic ، Oxidase Mimic ، H۲O۲ Colorimetric Detection