Abstract: BACKGROUND: Copper sulfide nanoparticles have good antibacterial and wound healing effects, but they are not easy to persist in wounds, which limits their application to a certain extent.
OBJECTIVE: To investigate the effect of copper sulfide nanoparticles loaded thermosensitive hydrogel Pluronic F127 on infected wound healing in rats. 
METHODS: Copper sulfide nanoparticles, thermosensitive hydrogel Pluronic F127, and copper sulfide nanoparticles loaded Pluronic F127 were prepared respectively. Twenty-four male Wistar rats were taken to establish a wound model of Staphylococcus aureus on the back. One day later, they were randomly divided into three groups (n=8). In the control group, the wounds were injected with PBS. In the hydrogel group, the wounds were covered with thermosensitive hydrogel pluronic F127. In the nanoparticle group, the wounds were covered with copper sulfide nanoparticles loaded with thermosensitive hydrogel Pluronic F127. On day 3 after wound treatment, the bacteriological test of the wound was performed. On day 14 after wound treatment, the wound area was measured; blood was collected to test the liver and kidney functions of the rats and the histological changes of the wound and main organs were observed.
RESULTS AND CONCLUSION: (1) On day 3 of wound treatment, the number of colonies in the wound tissue was significantly lower in the nanoparticle group than that of the control and hydrogel groups (P < 0.05). (2) On day 14 of wound treatment, the wound area of the rats was smaller in the nanoparticle group than that in the control and hydrogel groups (P < 0.05). (3) On  day 14 of wound treatment, hematoxylin-eosin staining of wound tissue displayed that relatively dense and mature granulation tissue was seen in the nanoparticle group, while a large number of loose and immature granulation tissues were seen in the control and hydrogel groups. Masson staining exhibited that loose collagen tissue was seen in the control and hydrogel groups, and dense collagen tissue was seen in the nanoparticle group. (4) There was no significant difference in liver and kidney function index values among the three groups (P > 0.05). No obvious histopathological changes were found in the main organs such as heart, liver, spleen, lung, and kidney. (5) Pluronic F127 hydrogel loaded copper sulfide nanoparticles could obviously inhibit the growth of bacteria and promote the healing of infectious wounds.

Key words: copper sulfide nanoparticle, hydrogel, antibacteria, wound healing, Staphylococcus aureus, rat, infection model