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 <i>Vibrio vulnificus (V. vulnificus)</i>. 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 <i>V. vulnificus</i> following photothermal treatment (PTT). Our analysis revealed significant membrane disruption, attenuation of virulence determinants, and global metabolic reprogramming in PTT-treated bacterial cells. <i>In vitro</i> assessments demonstrated the hydrogel's biocompatibility, while <i>in vivo</i> 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.