Thermal and Structural Properties of Silk Biomaterials Plasticized by Glycerol

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• 作者：Joseph E. Brown ; Stephen K. Davidowski ; Dian Xu ; Peggy Cebe ; David Onofrei ; Gregory P. Holland ; David L. Kaplan
• 刊名：Biomacromolecules
• 出版年：2016
• 出版时间：December 12, 2016
• 年：2016
• 卷：17
• 期：12
• 页码：3911-3921
• 全文大小：768K
• ISSN：1526-4602

文摘

The molecular interactions of silk materials plasticized using glycerol were studied, as these materials provide options for biodegradable and flexible protein-based systems. Plasticizer interactions with silk were analyzed by thermal, spectroscopic, and solid-state NMR analyses. Spectroscopic analysis implied that glycerol was hydrogen bonded to the peptide matrix, but may be displaced with polar solvents. Solid-state NMR indicated that glycerol induced β-sheet formation in the dried silk materials, but not to the extent of methanol treatment. Fast scanning calorimetry suggested that β-sheet crystal formation in silk-glycerol films appeared to be less organized than in the methanol treated silk films. We propose that glycerol may be simultaneously inducing and interfering with β-sheet formation in silk materials, causing some improper folding that results in less-organized silk II structures even after the glycerol is removed. This difference, along with trace residual glycerol, allows glycerol extracted silk materials to retain more flexibility than methanol processed versions.