NIR-responsive tissue-adaptive hydrogel for accelerating healing of seawater-immersed wounds

Seawater-immersed wounds pose a significant health risk owing to the high-salt and hypertonic environment of seawater, and the presence of various bacterial species, notably Vibrio vulnificus (V. vulnificus). Although a number of dynamically adhesive hydrogels have developed recently, these gels are often composed of dynamic networks, which lead to insufficient mechanical strength and short-term protection for wound surfaces. In this study, a GPS hydrogel with a covalent network based on gelatin-methacryloyl (GelMA), poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) (SBMA) has been developed. The GPS hydrogel demonstrated significantly enhanced mechanical properties compared with GelMA hydrogel, exhibiting 18-fold (501 % strain) and 299-fold (613 kJ/m³) improvements in tensile strain and toughness, respectively, along with a Young's modulus of 50.1 kPa and rapid 160 s gelation capability. Furthermore, the GPS hydrogel achieved exceptional photothermal conversion under 808 nm NIR irradiation, attaining 57 °C within 100 s to enable near-complete bacterial eradication (100 %). This study presented the first transcriptomic profiling of V. vulnificus following photothermal treatment (PTT). Our analysis revealed significant membrane disruption, attenuation of virulence determinants, and global metabolic reprogramming in PTT-treated bacterial cells. In vitro assessments demonstrated the hydrogel's biocompatibility, while in vivo evaluations revealed that GPS hydrogel significantly enhanced seawater immersed wound healing rates in rat models. Altogether, this study offered a promising solution for the long-term management of seawater-immersed wounds with a covalently-crosslinked photothermal antibacterial hydrogel dressing.