Sensitive Colorimetric Detection of Cholesterol Using MIL-101 (Fe)-NH2 Nanozymes as Peroxidase Mimics

Abstract

The precise quantitative assessment of cholesterol levels is highly significant in the clinical diagnosis of cardiovascular disease. In this study, nanozymatic MOF with peroxidase-like activity, MIL-101(Fe)-NH2 and cholesterol oxidase (ChOx) have been coupled together to provide a facile approach for cholesterol detection through a cascade reaction. Cholesterol is oxidized by ChOx to create H2O2 which in turn can be utilized for 3,3',5,5'-tetramethylbenzidine (TMB) oxidation by the highly catalytic MIL-101(Fe)-NH2. This results in the production of a blue-colored product, easily detected even by naked eyes. With a detection limit of 1.86±0.04 μM, the developed detection method enables cholesterol sensing over a broad range of 10-1000 μM. Furthermore, lower Km and higher Vmax (than HRP) demonstrate improved peroxidase-like catalytic activity and greater cholesterol oxidase (ChOx) binding affinity, which leads to good biosensor stability and resilience to environmental interferences. © 2024 IEEE.