Figure 5. Evaluation of hydrogel in promoting second-degree scald wound repairment. (A) Schematic diagram of scald wound molding and the timeline of hydrogel therapeutic effect assay. (B) Representative images of the wound at day 0, 1, 3, 7, 14, and the diagrams of time-evolved wound areas. (C) Statistical analysis of the wound area (n = 3) (D) Photographs of bacteria from the wound tissues on day 3, cultured on Luria-Bertani (LB) medium and mannitol salt agar medium (MSA) after diluting 1000-fold, and blood vessels at the wound sites on day 21 after different treatments. Vascular regeneration analysis at the wound sites on day 21 was counted by (E) the number of master junctions and (F) the number of mashes.
The size of the wound in all groups tended to decrease, but compared with the control group and the blank hydrogel group, the wound healing speed of ANVs or THB@ANVs encapsulated hydrogels can be significantly improve. On the 3th day, due to the good antibacterial effect of THB, the bacteria infection in THB@ANVs hydrogel group were significantly inhibited, only few bacterial colonies can be obseved after white light photodynamic treatment (Figure 5D), which proved that THB@ANVs hydrogel could effectively kill and inhibit the bacteria on the wound. At the same time, it can be observed that there was already obvious granulation tissue on the wound surface of the THB@ANVs hydrogel group on 3th day. The wound area of ANVs or THB@ANVs hydrogels on the 7th and 14th day of wound healing are smaller than that of the other two groups, which proves the healing promoting ability of the ANVs. On day 21, higher vascular densities can be observed in ANVs and THB@ANVs hydrogel group with high numbers of vascular master junctions and mashes (Figure 5D~5F). It proves that ANVs can increase the supply of nutrients to wounds by promoting angiogenesis, thereby accelerating wound healing. The above results indicate that photodynamic THB@ANVs encapsulated hydrogel is a good material to prevent bacterial infection at the defected sites and promoting wound repair at the same time.