Light-driven dual-mode antibacterial composite based on chitosan, hollow carbon matrix, and fucoxanthin for preserving Undaria pinnatifida.

Aiming at the microbial spoilage issue of perishable products, this study rationally designs a visible-light-driven antibacterial packaging system by incorporating hollow carbon matrix-fucoxanthin (HCM-FX) nanofillers into a chitosan (CS) matrix. The system overcomes inherent limitations of both components, achieving synergistic antimicrobial performance. Key innovations include: (i) a Z-scheme heterojunction that suppresses charge recombination and extends visible-light absorption; (ii) Enhanced carrier functionality that mitigates aqueous aggregation of FX photosensitizers; (iii) Spatially optimized bacterial inactivation was achieved through electrostatic attraction mediated by the positive charge inherent in CS and light-induced ROS generation, which collectively disrupt cellular integrity, inhibit antioxidant defenses and degrading DNA, enabling 99% sterilization within 30 min under visible light irradiation. The engineered CS-HCM-FX film extends the shelf-life of Undaria pinnatifida stipes by 2.5 times to 15 days. Biocompatibility is confirmed by low hemolysis (<5%) and high cell viability (>80%), underpinning practical applicability. This work provides a sustainable strategy for designing light-activated antimicrobial interfaces.