Target-triggered formation of photo-induced nanozyme for the selective and amplified detection of selenium

Selenium (Se) is an essential trace element for human, its intake must be maintained within a narrow range to avoid deficiency and toxicity. Current methods of Se detection are limited by high cost, complex operation, and poor suitability for rapid on-site analysis. Herein, a colorimetric sensing platform was developed for the highly sensitive and selective detection of Se in foods based on the in-situ generation of Se nanoparticles (SeNPs) via hydride generation (HG). The SeNPs exhibit photo-induced oxidase-like activity, enabling the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) under irradiation of light emitting diode (LED) providing signal amplification. The assay demonstrates a wide linear range from 1 to 100 ng/mL and a low detection limit of 0.12 ng/mL. Furthermore, smartphone was successfully used of as readout platform. Successful application to Se-rich food samples (e.g., vinegar, salt, rice, and eggs) detection confirmed its practicality and reliability, offering a promising alternative to Se detection.