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.