Rational design of Ag-doped MnFe2O4/HNTs for peroxidase-mimicking activity and colorimetric sensing of uric acid in human serum

Mimicking enzyme have significantly advanced sensing assays by replicating native enzyme functions, yet achieving both high catalytic activity and easy recyclability remains a challenge. In this study, Ag-doped MnFe2O4/halloysite nanotubes (HNTs) were rationally designed as a novel nanozyme by depositing in-situ Ag and MnFe2O4 nanoparticles onto HNTs. The resulting nanocomposite exhibited excellent peroxidase-like activity along with magnetic properties. Leveraging these features, a highly efficient and sensitive colorimetric system for detecting uric acid (UA) was developed. The Ag-doped MnFe2O4/HNTs catalyzed the oxidation of 3,3′,5,5′-tetramethylbenzidine in the presence of H2O2, causing a color change from colorless to blue. The system showed a linear absorbance response to UA concentrations ranging from 1 to 20 μM, with a detection limit of 59 nM. Mechanistic studies revealed that reactive oxygen species intermediates (1O2) were generated through the decomposition of H2O2, leading to peroxidase-like activity in the Ag-doped MnFe2O4/HNTs. The assay was successfully applied to detect UA in human serum with recoveries over 99.68 %. This study indicates the successful application of Ag-doped MnFe2O4/HNTs for colorimetric UA detection in human serum. This research introduces a novel approach for designing recyclable, high-performance mimicking enzyme and establishes an effective colorimetric sensing platform for UA detection in human serum. [Display omitted] •The magnetic Ag-doped MnFe2O4/HNTs was designed and successfully synthesized.•The designed Ag-doped MnFe2O4/HNTs was proved to possess magnetism and intrinsic peroxidase-like activity.•A colorimetric sensing system for uric acid was constructed.•The sensing system has the advantages of easy recyclability, high sensitivity and selectivity.•The uric acid monitoring results in human serum samples using the sensing system are satisfactory.