Visible light-stimulated chitosan-stabilized selenium nanozyme for tri-modal photocatalysis, ferroptosis-like...

This study presents a novel metal-free photonanozyme selenium nanoparticles (SeNPs) stabilized with natural chitosan (CS), through a green reduction method. The CS@SeNPs exhibited uniform spherical morphology (61 nm), high colloidal stability (ζ-potential: +27.7 mV) and light-stimulated oxidase-like (OXD-like) catalytic activity under visible blue light irradiation. Under blue light (420 nm, 213 mW/cm²), CS@SeNPs completely eradicated both bacteria and biofilms within 5-15 min. Through reactive oxygen species (ROS) generation, CS@SeNPs with BL irradiation demonstrated excellent antibacterial and biofilm eradication capacity through synergistic membrane destabilization, photocatalytic inactivation (PCI) and a ferroptosis-like cell death mechanism. Furthermore, practical applications of CS@SeNPs in fruit preservation and washing water disinfection demonstrated their potential in enhancing food safety and reducing microbial contamination risks. Based on the light-activated enzymatic activity, a rapid dual-mode colorimetric and fluorometric biosensor for ascorbic acid (AA) detection was constructed, offering high sensitivity (LOD: 1.21-3.78 μM) and wide linear ranges. This work provides new insights into the design of a multifunctional nanoplatform integrating enzymatic mimicry and antimicrobial efficacy to effectively support various applications in fruit juice processing plants.