Battery-free, sprayable, wireless photothermal micro/nanofibre dressing with thermal-induced crosslinked polypyrrole for accelerated diabetic wound healing

Diabetic chronic wounds remain a formidable clinical challenge because hyperglycaemia triggers microangiopathy, persistent inflammation, and oxidative stress that disrupt the orderly cascade of tissue repair. Near-infrared (NIR) phototherapy offers a wireless, non-invasive, electromagnetic approach that has shown clinical success, yet conventional devices are typically bulky, expensive, and require prolonged treatment times factors that hamper patient adherence and therapeutic efficacy. To address these limitations, we developed a lightweight, sprayable, wearable phototherapeutic system that couples a flexible, battery-free bandage with a portable NIR light source. The bandage is an ultra-flexible electrospun micro/nanofibre membrane composed of sodium-chloride–templated polypyrrole, polyethyleneimine, and PLGA; it converts incident NIR energy into heat and delivers it directly to the wound site. Electromagnetic simulations and empirical measurements confirm that the spray-deposited bandage generates a homogeneous photothermal field suitable for wound therapy. Under 808 nm irradiation, the membrane rapidly reaches around 45 °C within 3 min and withstands repeated on/off cycles without performance loss. This mild hyperthermia up-regulates heat-shock proteins and mitigates reactive oxygen species. In vitro, the membrane supports L929 fibroblast proliferation and exhibits negligible cytotoxicity at extract concentrations up to 30 %. In streptozotocin-induced diabetic Wistar rats, a single application of the bandage followed by daily 5-min NIR illumination accelerates wound closure by day 7, compared with untreated controls, and is accompanied by potentially reduced inflammatory pathogenic substance infiltrates. Collectively, these results demonstrate that integrating conductive and photothermal cues within a wearable scaffold offers a simple yet powerful strategy to overcome the multifactorial barriers of diabetic wound healing and underscores the translational promise of this intelligent, light-responsive dressing.