This study aimed to develop a silk fibroin (SF)-film for the treatment of chronic diabetic wounds. Silk fibroin was purified through a newly developed heating degumming (HD) process and casted on a hydrophobic surface to form SF-films. The process allowed the fabricated film to achieve a 42% increase in transparency and a 32% higher proliferation rate for BALB/3T3 fibroblasts compared to that obtained by conventional alkaline degumming treatment. Fourier transform infrared analysis demonstrated that secondary structure was retained in both HD- and alkaline degumming-derived SF preparations, although the crystallinity of beta-sheet in SF-film after the HD processing was slightly increased. This study also investigated whether conjugating insulin-like growth factor-1 (IGF-1) would promote diabetic wound healing and what the optimal dosage is. Using BALB/3T3 cells grown in hyperglycemic medium as a model, it was demonstrated that the optimal IGF-1 dosage to promote the cell growth was approximately 0.65 pmol. Further analysis of wound healing in a diabetic mouse model indicated that SF-film loaded with 3.25 pmol of IGF-1 showed significantly superior wound closure, a 13% increase at the 13th day after treatment relative to treatment with 65 pmol of free IGF-1. Improvement in diabetic wound healing was exerted synergistically by SF-film and IGF-1, as reflected by parameters including levels of re-epithelialization, epithelial tissue area, and angiogenesis. Finally, IGF-1 increased the epithelial tissue area and micro-vessel formation in a dose-dependent manner in a low dosage range (3.25 pmol) when loaded to SF-films. Together, these results strongly suggest that SF-film produced using HD and loaded with a low dosage of IGF-1 is a promising dressing for diabetic wound therapy.

中文翻译：

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用于糖尿病伤口愈合的类胰岛素生长因子 1 共轭家蚕丝素膜：体外和体内的制备、理化特性表征和剂量优化

本研究旨在开发一种用于治疗慢性糖尿病伤口的丝素蛋白 (SF) 薄膜。丝素蛋白通过新开发的加热脱胶 (HD) 工艺进行纯化，并浇铸在疏水表面上以形成 SF 膜。与通过常规碱性脱胶处理获得的薄膜相比，该工艺使制成的薄膜的透明度提高了 42%，BALB/3T3 成纤维细胞的增殖率提高了 32%。傅里叶变换红外分析表明，二级结构保留在 HD 和碱性脱胶衍生的 SF 制剂中，尽管 HD 处理后 SF 薄膜中β-折叠的结晶度略有增加。该研究还调查了结合胰岛素样生长因子-1 (IGF-1) 是否会促进糖尿病伤口愈合以及最佳剂量是多少。使用在高血糖培养基中生长的 BALB/3T3 细胞作为模型，证明了促进细胞生长的最佳 IGF-1 剂量约为 0.65 pmol。对糖尿病小鼠模型伤口愈合的进一步分析表明，负载 3.25 pmol IGF-1 的 SF 膜显示出显着优越的伤口闭合，相对于用 65 pmol 游离 IGF-1 治疗，治疗后第 13 天增加了 13% . SF-film 和 IGF-1 可协同改善糖尿病伤口愈合，这反映在再上皮化水平、上皮组织面积和血管生成水平等参数上。最后，当加载到 SF 膜时，IGF-1 在低剂量范围 (3.25 pmol) 内以剂量依赖性方式增加上皮组织面积和微血管形成。一起，