All-in-one hydrogel patches with sprayed bFGF-loaded GelMA microspheres for infected wound healing studies

We designed a high-viscosity antimicrobial hydrogel patch (HDC-bFGF), using 1,4-butanediol dimethacrylate as the cross-linking agent, with cross-linked hyaluronic acid serving as the backbone. Additionally, dopamine and chitosan were incorporated as cross-linkers, and the surface was spray-coated with microspheres containing bFGF. This hydrogel patch possesses anti-inflammatory, antioxidant, antimicrobial, and angiogenesis-promoting properties, which can accelerate the healing of wounds. It significantly accelerated the healing of infected wounds in an acute wound model in mice. [Display omitted] The current wound healing process faces numerous challenges such as bacterial infection, inflammation and oxidative stress. However, wound dressings used to promote wound healing, are not well suited to meet the clinical needs. Hyaluronic acid (HA) not only has excellent water absorption and good biocompatibility but facilitates cell function and tissue regeneration. Dopamine, on the other hand, increases the overall viscosity of the hydrogel and possesses antioxidant property. Furthermore, chitosan exhibits outstanding performance in antimicrobial, anti-inflammatory and antioxidant activities. Basic fibroblast growth factor (bFGF) is conducive to cell proliferation and migration, vascular regeneration and wound healing. Hence, we designed an all-in-one hydrogel patch containing dopamine and chitosan framed by hyaluronic acid (HDC) with sprayed gelatin methacryloyl (GelMA) microspheres loaded with bFGF (HDC-bFGF). The hydrogel patch exhibits excellent adhesive, anti-inflammatory, antioxidant and antibacterial properties. In vitro experiments, the HDC-bFGF hydrogel patch not only showed significant inhibitory effect on RAW cell inflammation and Staphylococcus aureus (S. aureus) growth but also effectively scavenged free radicals, in addition to promoting the migration of 3 T3 cells. In the mice acute infected wound model, the HDC-bFGF hydrogel patch adhered to the wound surface greatly accelerated the healing process via its anti-inflammatory and antioxidant activities, bacterial inhibition and pro-vascularization effects. Therefore, the multifunctional HDC-bFGF hydrogel patch holds great promise for clinical application.