Plasma-engineered chitosan couples red-light bioenergetics to diabetic wound regeneration through programmable microenvironments.

Diabetic wounds remain trapped in a non-healing loop driven by oxidative stress, impaired bioenergetics, and persistent inflammation. Here, we report a cold atmospheric plasma (CAP)-engineered chitosan-microalgae (CS-CHL) photobioactive dressing that converts a carbohydrate matrix into a programmable photosynthetic interface for wearable 660-nm activation. CAP remodeled the CS microenvironment in a duration-dependent manner, as verified by FTIR/XRD/NMR, and yielded a distinct optimum at 30 s with the most favorable polymer reorganization and coupling to CHL. This "just-right" window tuned photochemical branching under red light, showing the strongest oxygen-sensitive response as reflected by the lowest O₂ quenching index (~66.3%, indicating the greatest probe quenching and thus higher O₂ availability), while simultaneously enhancing reductive bioenergetic outputs, including hydrogen production (~117.6%) and MPP-Production (~116.4%), accompanied by the strongest light-responsive electrochemical signal. In an STZ-induced diabetic full-thickness wound model, CS-CHL + 660 nm accelerated macroscopic wound closure versus wound-only and CS controls, while systemic hematological indices remained comparable across groups. Mechanistic tissue profiling further supported coordinated inflammation suppression, angiogenic/regenerative recovery, ROS reduction, mitochondrial functional restoration, and activation of mitophagy/autophagy-associated pathways. Collectively, CAP-tuned carbohydrate microenvironments provide a powerful route to program microalgal photobioenergetics and enable light-assisted diabetic wound repair.