A self-cascade triple-functional AuNPs-modified FeCe-MOF-derived carbon material for enzyme-free colorimetric detection of glucose and cholesterol

A novel AuNPs-modified FeCe-MOF derived carbon material (FeCe@C-AuNPs) nanozyme was developed for the colorimetric detection of glucose and cholesterol. In the constructed system, AuNPs mainly exhibited oxidase-like activity toward glucose and cholesterol oxidation, generating H₂O₂, while FeCe@C served as a peroxidase mimic to activate H₂O₂ and produce hydroxyl radicals (•OH), which subsequently oxidized colorless 3,3',5,5'-tetramethylbenzidine (TMB) into blue ox-TMB. The synergistic interaction among Fe, Ce, the carbon matrix, and AuNPs facilitated interfacial electron transfer, promoted H₂O₂ activation, and enhanced the overall cascade catalytic performance. The glucose assay exhibited two linear ranges of 0-2 and 2-10 mM, whereas cholesterol showed a linear range of 0-10 µM, with detection limits of 0.19 mM and 0.85 µM, respectively. Glucose and cholesterol can be determined under their respective optimized pH conditions using the same FeCe@C-AuNPs platform. The method was successfully applied to commercial beverage and milk samples, yielding recoveries of 94.02-106.93%. Moreover, FeCe@C-AuNPs-3 maintained stable catalytic activity and detection performance during storage for 60 days. This study provides a promising strategy for constructing efficient cascade nanozyme systems for biomolecule sensing.