Enhanced peroxidase‐like activity of MnFe₂O₄ nanoparticles on halloysite nanotubes for uric acid detection

Abstract Nanozymes have significantly advanced sensing assays by replicating native enzyme functions. However, designing nanozymes with high catalytic activity and easy recyclability remains challenging. The study presented here has resulted in the development of a highly efficient and sensitive colorimetric system for the detection of uric acid, utilizing MnFe 2 O 4 @HNTs—a novel composite material consisting of MnFe 2 O 4 loaded onto halloysite nanotubes. These nanocomposites exhibited outstanding peroxidase‐like activity and attractive magnetic properties. The catalytic efficiency of the MnFe 2 O 4 @HNTs in the oxidation of 3,3′,5,5′‐tetramethylbenzidine, in the presence of H 2 O 2 , was remarkable, leading to a distinct color change from colorless to blue. A linear relationship was observed between absorbance and UA concentration in the range of 1–20 μM, with a detection limit as low as 52 nM. Mechanistic investigations revealed that reactive oxygen species (ROS), specifically singlet oxygen ( 1 O 2 ), were generated through the decomposition of H 2 O 2 , which is responsible for the peroxidase‐like activity demonstrated by the MnFe 2 O 4 @HNTs. The method showed minimal interference from serum substances and high selectivity. Magnetic MnFe 2 O 4 allowed easy separation and maintained over 95% activity after seven reuse cycles. The developed assay was successfully applied to the detection of uric acid in human serum, achieving recoveries greater than 98.60%. This research significantly advances the design of recyclable high‐performance nanozymes and establishes an effective colorimetric sensing platform for UA detection in clinical samples, potentially improving diagnostic tools for healthcare applications.