In situ microscopic studies on the structures and phase behaviors of SF/PEG films using solid-state NMR and Raman imaging
In situ microscopic studies on the structures and phase behaviors of SF/PEG films using solid-state NMR and Raman imaging
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使用固态核磁共振和拉曼成像对 SF/PEG 薄膜的结构和相行为进行原位显微研究
DOI：
10.1039/c6cp03314h
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发表时间：
2016-06-28
影响因子：
3.3
通讯作者：
Zhou, Ping
中科院分区：
文献类型：
--
作者：
Chen, Congheng;Yao, Ting;Zhou, Ping
为了克服丝素蛋白（SF）基材料的缺点，SF已与一些聚合物共混。在使用共混材料之前，理解共混物的结构和相行为被认为是必不可少的。在这项研究中，固态C-13 CP-MAS NMR和拉曼成像技术被用来研究SF与聚乙二醇（PEG）的共混物的结构和相行为的分子量从2到20 kDa的变化和SF/PEG的共混比从95/5到70/30（w/w%）在分子和微观水平。结果表明，当PEG含量一定时，SF向β-折叠构象的转变随PEG含量的增加而增加，而形成的β-折叠构象的量随PEG分子量的增加而减少。SF与PEG存在一定的不相容性。在SF/PEG共混膜中发生了“海”和“岛”相分离。SF主要存在于“海”结构域，而PEG主要存在于“岛”结构域。在SF与PEG的界面处，SF的构象变为β-折叠，而在富含蛋白质的结构域中，SF仍保持无规卷曲和/或螺旋构象。这些观察结果表明，可以通过控制共混体系中PEG的分子量和含量来制备特定预期的材料，例如基于丝的微球或支架材料。
In order to overcome the drawbacks of silk fibroin (SF)-based materials, SF has been blended with some polymers. Before using the blend material, understanding of the structures and phase behaviors of the blend is thought to be essential. In this study, solid-state C-13 CP-MAS NMR and Raman imaging techniques were used to study the structures and phase behaviors of blends of SF with polyethylene glycol (PEG) at a molecular weight that varied from 2 to 20 kDa and a blend ratio of SF/PEG from 95/5 to 70/30 (w/w%) at the molecular and microscopic levels. It is found that the conformational transition of SF to the beta-sheet increased as the PEG content increased, while the amount of the formed beta-sheet conformers was decreased as the PEG molecular weight increased for a given content. It is also observed that SF was incompatible with PEG to some extent. The phase separation into "sea'' and "island'' domains took place in the SF/PEG blend films. SF was dominantly present in the "sea'' domain, while PEG in the "island'' domains. The conformation of SF in the interface between SF and PEG was changed to the beta-sheet, while that in the protein-rich domain remained in the random coil and/or helix conformation. These observations suggest that the specifically expected materials, for example, the silk-based microspheres or scaffold materials can be manufactured by controlling the molecular weight and content of PEG in the blend system.