Liu Jian, Chen Huijuan, Wang Yongfeng, Li Gang, Zheng Zhaozhu, Kaplan David L, Wang Xiuli, Wang Xiaoqin
National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China.
College of Basic Medical Science, Dalian Medical University, Dalian 116044, People's Republic of China.
ACS Biomater Sci Eng. 2020 Mar 9;6(3):1641-1649. doi: 10.1021/acsbiomaterials.9b01721. Epub 2020 Feb 13.
Silk fibroin (SF) scaffolds are widely used in tissue engineering due to their biocompatibility and slow biodegradability. However, the relatively stiff mechanical properties and low permeability of these systems can limit some applications. In this study, a new type of water-stable silk sponge (ASF-PEG-S) was obtained by inducing nanoparticle (50-300 nm in diameter) formation in SF solution by autoclaving followed by freeze-drying and rinsing the dry sponges with low-molecular weight (400 Da) polyethylene glycol (PEG400) to induce SF β-sheet structure formation and thus stability in water. With further extraction, the SF nanoparticles embedded in the sponges were removed, leaving nanopores in the walls of round-shaped micro-size pores. The unique pore structure resulted in enhanced permeability and flexibility of ASF-PEG-S when compared to other types of SF sponges, especially with respect to commonly used methanol-annealed SF sponges. In addition, ASF-PEG-S absorbed water nearly 40 times more than its dry weight, while the methanol-annealed sponges absorbed half this amount. When human fibroblasts were seeded and cultured on ASF-PEG-S versus traditional SF methanol-processed sponges, improved cell encapsulation, distribution, and consistency in growth were observed, suggesting utility in tissue engineering and tissue repair applications in the future.
丝素蛋白（SF）支架因其生物相容性和缓慢的生物降解性而被广泛应用于组织工程。然而，这些系统相对较硬的机械性能和低渗透性可能会限制某些应用。在本研究中，通过高压灭菌在SF溶液中诱导形成纳米颗粒（直径50 - 300 nm），随后进行冷冻干燥并用低分子量（400 Da）聚乙二醇（PEG400）冲洗干燥的海绵，以诱导SFβ-折叠结构的形成，从而获得一种新型的水稳定丝海绵（ASF-PEG-S）。通过进一步提取，去除嵌入海绵中的SF纳米颗粒，在圆形微米尺寸孔的壁上留下纳米孔。与其他类型的SF海绵相比，独特的孔结构导致ASF-PEG-S的渗透性和柔韧性增强，特别是相对于常用的甲醇退火SF海绵。此外，ASF-PEG-S吸收的水分几乎是其干重的40倍，而甲醇退火海绵吸收的水分量仅为其一半。当将人成纤维细胞接种并培养在ASF-PEG-S与传统的经甲醇处理的SF海绵上时，观察到细胞包封、分布和生长一致性得到改善，这表明其在未来的组织工程和组织修复应用中具有实用性。
