2.6.1 In vivo wound assay
Skin is the main barrier that protects the body against external damage bacterial infection. Upon scald injury, bacteria can easily penetrate during the lengthy wound recovery process. In vitro studies have shown that the THB@ANVs hydrogel has great promise for bacteria resist and scald wound repair. Therefore, the deep second-degree scald wound model (16mm in diameter) of rat was successfully established using a scald equipment, with parameters set at 500 g, 95 ℃, 15s (Figure S15). As shown in Figure 5A, hydrogels were applied on the wound after debridement treatment, and S. aureus were dropped onto the wound surface to verify the anti-infectious ability of THB@ANVs hydrogel. Different to human, the primary wound closure of rat relies more on contracture of the loose skin, rather than re-epithelialization and deposition of connective tissue. Thus, silicone fixing rings are used to increase the tension of skins in the wound healing assessment of rats. The photographic images of the wound appearances on days 1, 3, 7, and 14 time points taken after treatment with PBS, blank hydrogels, ANVs hydrogels or THB@ANVs hydrogels on the deep second-degree scald model of rats are shown in Figure 5B. To quantitatively determine the wound regeneration, the percentages of wound sizes were measured and analyzed (figure 5C).