Structure and properties of silk hydrogels
Structure and properties of silk hydrogels
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DOI：
10.1021/bm0345460
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发表时间：
2004-05-01
影响因子：
6.2
通讯作者：
Kaplan, DL
中科院分区：
文献类型：
--
作者：
Kim, UJ;Park, JY;Kaplan, DL
通过渗透应力对丝素蛋白在水溶液中的浓度控制进行了研究，以评估其与凝胶形成以及与此过程相关的结构、形态和功能（力学）变化的关系。还研究了在丝素蛋白水溶液体内加工过程中可能具有重要影响的环境因素，以确定它们对该过程的贡献。丝素蛋白水溶液的凝胶化受温度、Ca²⁺、pH和聚环氧乙烷（PEO）的影响。凝胶化时间随着蛋白质浓度的增加、pH的降低、温度的升高、Ca²⁺的添加以及PEO的添加而减少。添加K⁺时未观察到凝胶化时间的变化。凝胶化时，丝素蛋白的无规卷曲结构转变为β - 折叠结构。基于扫描电子显微镜，丝素蛋白浓度>4 wt%的水凝胶呈现出网络状和海绵状结构。随着丝素蛋白浓度或凝胶化温度的升高，冷冻干燥水凝胶的孔径变小。在Ca²⁺存在下形成的冷冻干燥水凝胶，随着该离子浓度的增加，其孔径变大。水凝胶的机械抗压强度和模量随着蛋白质浓度和凝胶化温度的增加而增加。这些研究结果深入了解了丝素蛋白在水溶液加工过程中在腺体中发生的溶胶 - 凝胶转变，同时也为将这些蛋白质在体外加工成有用的新材料提供了重要的见解。
Control of silk fibroin concentration in aqueous solutions via osmotic stress was studied to assess relationships to gel formation and structural, morphological, and functional (mechanical) changes associated with this process. Environmental factors potentially important in the in vivo processing of aqueous silk fibroin were also studied to determine their contributions to this process. Gelation of silk fibroin aqueous solutions was affected by temperature, Ca2+, pH, and poly(ethylene oxide) (PEO). Gelation time decreased with increase in protein concentration, decrease in pH, increase in temperature, addition of Ca2+, and addition of PEO. No change of gelation time was observed with the addition of K+. Upon gelation, a random coil structure of the silk fibroin was transformed into a beta-sheet structure. Hydrogels with fibroin concentrations > 4 wt % exhibited network and spongelike structures on the basis of scanning electron microscopy. Pore sizes of the freeze-dried hydrogels were smaller as the silk fibroin concentration or gelation temperature was increased. Freeze-dried hydrogels formed in the presence of Ca2+ exhibited larger pores as the concentration of this ion was increased. Mechanical compressive strength and modulus of the hydrogels increased with increase in protein concentration and gelation temperature. The results of these studies provide insight into the sol-gel transitions that silk fibroin undergoes in glands during aqueous processing while also providing important insight in the in vitro processing of these proteins into useful new materials.