Department of Chemistry, Istanbul Technical University, 34469 Istanbul, Turkey.
Biomacromolecules. 2013 Mar 11;14(3):719-27. doi: 10.1021/bm3018033. Epub 2013 Feb 13.
Silk fibroin cryogels with remarkable properties were obtained from frozen fibroin solutions (4.2-12.6%) at subzero temperatures between -5 and -22 °C. This was achieved by the addition of ethylene glycol diglycidyl ether (EGDE) into the cryogelation system. EGDE triggers the conformational transition of fibroin from random coil to β-sheet structure and hence fibroin gelation. One of the unique features of fibroin cryogels is their elasticity that allows them to resist complete compression without any crack development, during which water inside the cryogel is removed. The compressed cryogel immediately swells during unloading to recover its original shape. The scaffolds obtained by freeze-drying of the cryogels consist of regular, interconnected pores of diameters ranging from 50 to 10 μm that could be regulated by the synthesis parameters. The mechanical compressive strength and the modulus of the scaffolds increase with decreasing pore diameter, that is, with decreasing gelation temperature or, with increasing fibroin or EGDE concentrations in the feed. The scaffolds produced at 12.6% fibroin exhibit a very high compressive modulus (50 MPa) making them good candidates as bone scaffold materials.
从冷冻丝素溶液（4.2-12.6%）在零下温度（-5 至-22°C）下获得具有显著性能的丝素 cryogel。这是通过将乙二醇二缩水甘油醚（EGDE）添加到 cryogelation 系统中来实现的。EGDE 触发丝素从无规卷曲到 β-折叠结构的构象转变，从而使丝素凝胶化。丝素 cryogel 的独特特征之一是其弹性，使其能够在没有任何裂纹发展的情况下抵抗完全压缩，在此过程中，cryogel 内的水被除去。压缩的 cryogel 在卸载时立即膨胀，以恢复其原始形状。通过 cryogel 的冷冻干燥获得的支架由直径为 50 至 10 μm 的规则、相互连接的孔组成，这些孔可以通过合成参数进行调节。支架的机械压缩强度和模量随着孔径的减小而增加，即随着凝胶化温度的降低，或者随着进料中丝素或 EGDE 浓度的增加而增加。在 12.6%丝素下制备的支架表现出非常高的压缩模量（50 MPa），使其成为骨支架材料的良好候选物。
