Evaluation of silk fibroin/curcumin composite film for promoting wound healing / 中国组织工程研究

ABSTRACT

BACKGROUND: In the previous study, we have successfully prepared a silk fibroin/curcumin composite film, which possesses good physicochemical properties, sustained-release properties, antibacterial activity and biocompatibility. OBJECTIVE: To further observe the effect of the prepared silk fibroin/curcumin composite film, as the wound dressing, in the field of wound healing. METHODS: The silk fibroin/curcumin composite film was prepared by referring to the previously established methods. The mechanical properties and light transmittance of the prepared composite film were then investigated. Escherichia coli and Staphylococcus aureus were used as strains. The plate-counting technique was applied to evaluate the antibacterial activity of the light illuminated silk fibroin/curcumin composite film, silk fibroin/curcumin composite film without light exposure, and silk fibroin film without light exposure. The full-thickness excisional lesions were created on the dorsum of 20 Kunming mice. The wounds of 10 mice were covered with silk fibroin/curcumin composite film, and the wounds of other 10 mice were dressed with sterile gauze. The healing status and histological morphology of the wound sites were observed at 3, 7, and 14 days post operation. The animal experimental design and the protocols were approved by the Laboratory Animal Ethics Committee of Southwest University (approval number: IACUC-2019011). RESULTS AND CONCLUSION: (1) Compared to silk fibroin film, the fracture strength of silk fibroin/curcumin composite film increased significantly (P < 0.05), while the Young’s modulus of silk fibroin/curcumin composite film decreased significantly (P < 0.01). (2) Both silk fibroin film and the silk fibroin/curcumin composite film exhibited excellent transparency, but the silk fibroin/curcumin composite film showed a stronger absorption in visible light region at a wavelength of 400-450 nm. (3) Without light illumination, the silk fibroin/curcumin composite film exhibited stronger antibacterial activity than that of silk fibroin film. While, the silk fibroin/curcumin composite film with light illumination demonstrated stronger antibacterial activity than that of silk fibroin/curcumin composite film without light illumination. (4) The wound healing rate of the experimental group was higher than that of the control group at each time point (P <0.05). Analysis on histological morphology reveals that the length of regenerated epithelia of dermal tissue and the thickness of granulation tissue in the experimental group were greater than those in the control group at 3 and 7 days post operation (P < 0.01). While, the thickness of granulation tissue was smaller than that in the control group at 14 days post operation (P < 0.01). (5) The results indicated that the silk fibroin/curcumin composite film can facilitate skin wound healing.