Microenvironment-programmed self-activating cascaded chemodynamic antibacterial packaging film with NIR-regulated catalytic activity for prolonged food preservation

In this study, a nano-platform driven by the microenvironment and photo-controlled catalytic activity was meticulously designed, and a CaO 2 @CAFe functional filler was constructed by using chlorogenic acid as a phenolic ligand and ferric ion to co-encapsulate calcium peroxide, creating an antibacterial packaging system (CCF-CS) with in situ self-activation cascade catalytic activity and intelligent enhancement effect of near-infrared light response. In this system, the acidic microenvironment provided by the chitosan (CS) film matrix triggers the CaO 2 @CAFe particles to continuously release H 2 O 2 , the catalytic substrate in which peroxidase plays a role, and "substrate self-supply" is achieved through a cascade reaction. Moreover, the catalytic efficiency of the nanozymes can be positively modulated by the "smart switch" of near-infrared light, enabling a dual-mode antibacterial behavior of "on-demand burst and routine protection". The CCF 0.20 -CS film was 99.9 % effective in killing both bacteria and fungi, and significantly extended the shelf life of cherry tomatoes by 10 days. Furthermore, the film exhibits enhanced UV-shielding capability and improved mechanical strength, alongside validated biosafety. These optimal properties underscore the innovative potential and practical superiority of the CCF 0.20 -CS packaging system in addressing microbial contamination challenges in food preservation.