A functional hydrogel of dopamine-modified gelatin with photothermal properties for enhancing infected wound healing

Infected skin wound has gradually become a prevalent injury that affects overall health. Currently, biomaterials with good adhesion, efficient antibacterial properties, and angiogenesis are considered as a suitable way to effectively heal infected wound. Herein, a multifunctional hydrogel comprising gelatin, dopamine (DA), and ferric ions (Fe3+) was developed for infected wound healing. The modified gelatin-dopamine (Gel-DA) enhanced adhesive capability. Subsequently introducing ferric ions (Fe3+) to form Gel-DA-Fe3+ hydrogels by Fe3+ and catechol coordination bonds. The designed hydrogels demonstrated multifaceted functionality, encompassing photothermal antibacterial, angiogenesis, and so on. The introduction of DA enhanced the adhesion of Gel-DA-Fe3+ to the skin surface and might serve as a physical barrier to seal wound. Meanwhile, DA and Fe3+ jointly endowed good photothermal effects to composite hydrogels, which could eliminate over 95% of bacteria. In vitro results revealed that Gel-DA-Fe3+ hydrogels had good biocompatibility and promoted HUVECs migration and tube formation. Furthermore, in vivo studies confirmed that Gel-DA-Fe3+ hydrogels markedly expedited the wound healing of rats through eradicating bacteria, accelerating the deposition of collagen, and promoting angiogenesis. What's more, Gel-DA-Fe3+ hydrogels under near-infrared laser had a more pronounced ability for wound healing. Therefore, Gel-DA-Fe3+ hydrogels had great potential for application in bacteria-infected wound healing.