Preparation and antibacterial properties of an AgBr@SiO2/GelMA composite hydrogel

Pure gelatin hydrogels lack antibacterial function and have poor mechanical properties, which restrict their application in wound dressings. In this study, nanosized silver bromide-doped mesoporous silica (AgBr@SiO2) microspheres with hollow structures were prepared by a modified Stober method. The novel microspheres can not only release silver ions to treat bacteria but also release drugs to treat skin wound. Furthermore, AgBr@SiO2microspheres were modified with propyl methacrylate, incorporated into methacrylated gelatin (GelMA), and crosslinked by UV light to prepare AgBr@SiO2/GelMA dressings consisting of composite hydrogels. The results showed that the AgBr@SiO2microspheres could enhance the mechanical properties of the hydrogels. With the increase in the AgBr@SiO2concentration from 0.5 to 1 mg ml-1, the dressings demonstrated effective antimicrobial activity against bothStaphylococcus aureusandEscherichia coli. Furthermore, full-thickness skin woundsin vivowound healing studies with Sprague-Dawley rats were evaluated. When treated with AgBr@SiO2/GelMA containing 1 mg ml-1AgBr@SiO2, only 15% of the wound area left on day 10. Histology results also showed the epidermal and dermal layers were better organized. These results suggest that AgBr@SiO2/GelMA-based dressing materials could be promising candidates for wound dressings.