Electrospun Nanofibrous Functionalized With Drug Induces Healing And Anti-scar Effects

Purpose:This paper studies the effect of a silk fibroin/gelatin (SF/GT) electrospun nanofibrous dressing loaded with Astragaloside IV (AS) on deep partial-thickness burn wound and scar reduction. Its mechanism and application in scar-free healing are further discussed.Methods:1. Prepared the AS-loaded SF/GT-blended nanofibrous dressing with different ratios (SF/GT 100/0、SF/GT 75/25、SF/GT 25/75、SF/GT 0/100) by electrospinning nanotechnology. The optimal ratio of silk fibroin to gelatin was obtained by evaluating ATR-FTIR characteristics, mechanical properties, porosity, swelling rate, degradation, and release profile of the AS-loaded SF/GT nanofibrous dressing.2. Loaded AS into nanofibrous dressing and applied the nanofibrous dressing to deep second degree burn wounds of rats to investigate its healing effect.. 3. The AS-loaded SF/GT nanofibrous dressing was further used to heal the trauma of rats in order to study its effect on trauma healing. We tested the skin tissue samples during different phases of wound healing to research its mechanism.Results:1. As the composition of gelatin in the AS-loaded SF/GT nanofibrous dressing increases, the nanofibrous dressing shows a good capability in terms of ATR-FTIR characteristics, mechanical properties, porosity, swelling rate, degradation, and release profile. Taking all factors into consideration, we select the ratio (SF/GT 25/75) of silk fibroin to gelatin as the optimal one.2. Loading AS into (SF/GT 25/75)-blended nanofibrous dressing doesn’t have any effect on the capability of diameter, mechanical properties, porosity, swelling rate, biocompatibility of nanofibrous dressing. The release amount of AS is as high as 35%,80%,96% at 1h, 12h and 48h. In the observation of the pharmacodynamics in vivo, the AS-loaded SF/GT-blended nanofibrous dressing has a remarkable effect on burn wound healing, including accelerating wound healing, increasing angiogenesis, regulating newly formed types of collagen, and improving collagen organization. Therefore, burn wound healing and scar inhibitation can be achieved.3. Furthermore, the AS-loaded SF/GT-blended nanofibrous dressing is effective on trauma healing in terms of 1) improving local immune function of the surface of a wound and accelerating wound healing through increasing the amount of macrophage near the wound; 2) accelerating the division and proliferation of endothelial cells through stimulating the increase of the amount of VEGF, which leads to the generation of new vessels; 3) inhibiting scar formation to some extend by inhibiting the expression of fibroblast to α-SMA and reducing fibromuscular cells formation.Conclusion:AS-functionalized SF/GT nanofibrous dressing is an excellent topical therapeutic that could be applied to promoting healing and eliciting anti-scar effects on partial-thickness burn wound and trauma.