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.