The rapid manufacture of silk fibroin gels in mild conditions is an important subject in the field of silk-based biomaterials. In this study, the gelation of Antheraea pernyi silk fibroin (ASF) aqueous solution was in...The rapid manufacture of silk fibroin gels in mild conditions is an important subject in the field of silk-based biomaterials. In this study, the gelation of Antheraea pernyi silk fibroin (ASF) aqueous solution was induced by shearing, without chemical cross-linking agents. Simple shearing controlled and accomplished the steady and rapid conformational transition to β-sheets with ease. The conformational transformation and rapid gelation mechanisms of ASF induced by shearing were tracked and analyzed by circular dichroism spectrometry, Fourier transform infrared spectroscopy and X-ray diffractometry, then compared with Bombyx mori silk fibroin (BSF). ASF quickly formed hydrogels within 24 - 48 h after shearing under different shearing rates for 30 - 90 min, resulting in sol-gel transformation when the β-sheet content reached nearly 50%, which is the minimum content needed to maintain a stable hydrogel system in ASF. The gel structures remained stable once formed. The rapid gelation of ASF through shearing compared with BSF was achieved because of ASF’s alternating polyalanine-containing units, which tend to form α-helix structures spontaneously. Further, the entropic cost during the conformational transition from the α-helix to the β-sheet structure is less than the cost of the transition from the random coil structure. This method is a simple, non-chemical cross-linking approach for the promotion of rapid gelation and the protection of the biological properties of ASF, and it may prove useful for application in the field of biomedical materials.展开更多
The sol-gel transition behavior of Antherae pernyi silk fibroin(Ap-SF) has not been systematically investigated.In this work,the influence of environmental temperature,pH,the concentration of Ap-SF,K+ and Ca2+ on the ...The sol-gel transition behavior of Antherae pernyi silk fibroin(Ap-SF) has not been systematically investigated.In this work,the influence of environmental temperature,pH,the concentration of Ap-SF,K+ and Ca2+ on the gelation time,and the structural changes of Ap-SF in sol-gel transformation were studied.The results indicated that the gelation time of the Ap-SF aqueous solution decreased with the increase of the Ap-SF concentration and environmental temperature.The sol-gel transformation of Ap-SF was much more rapid than that of Bombyx mori silk fibroin under the same conditions.The Ap-SF was sensitive to changes in the concentration of Ca2+ and K+.Upon gelation,the random coil structure of the Ap-SF was significantly transformed into the β-sheet structure.展开更多
用溶胶-凝胶法制备了纳米二氧化钛再生丝素复合膜,并用扫描电镜(SEM)、X射线(XRD)、热重分析(TGA、DTG)对复合丝素膜的结构与性能进行了表征。结果表明:加入纳米二氧化钛颗粒后再生丝素膜的热转变温度提高;再生丝素的结晶构象由S ilk I...用溶胶-凝胶法制备了纳米二氧化钛再生丝素复合膜,并用扫描电镜(SEM)、X射线(XRD)、热重分析(TGA、DTG)对复合丝素膜的结构与性能进行了表征。结果表明:加入纳米二氧化钛颗粒后再生丝素膜的热转变温度提高;再生丝素的结晶构象由S ilk I向S ilk II转变,结晶度增加。展开更多
文摘The rapid manufacture of silk fibroin gels in mild conditions is an important subject in the field of silk-based biomaterials. In this study, the gelation of Antheraea pernyi silk fibroin (ASF) aqueous solution was induced by shearing, without chemical cross-linking agents. Simple shearing controlled and accomplished the steady and rapid conformational transition to β-sheets with ease. The conformational transformation and rapid gelation mechanisms of ASF induced by shearing were tracked and analyzed by circular dichroism spectrometry, Fourier transform infrared spectroscopy and X-ray diffractometry, then compared with Bombyx mori silk fibroin (BSF). ASF quickly formed hydrogels within 24 - 48 h after shearing under different shearing rates for 30 - 90 min, resulting in sol-gel transformation when the β-sheet content reached nearly 50%, which is the minimum content needed to maintain a stable hydrogel system in ASF. The gel structures remained stable once formed. The rapid gelation of ASF through shearing compared with BSF was achieved because of ASF’s alternating polyalanine-containing units, which tend to form α-helix structures spontaneously. Further, the entropic cost during the conformational transition from the α-helix to the β-sheet structure is less than the cost of the transition from the random coil structure. This method is a simple, non-chemical cross-linking approach for the promotion of rapid gelation and the protection of the biological properties of ASF, and it may prove useful for application in the field of biomedical materials.
基金supported by the National Basic Research Program of China (Grant No 2005CB623902)the National Natural Science Foundation of China (Grant No 30970714)College Natural Science Research Project of Jiangsu Province (Grant No 07KJA43010)
文摘The sol-gel transition behavior of Antherae pernyi silk fibroin(Ap-SF) has not been systematically investigated.In this work,the influence of environmental temperature,pH,the concentration of Ap-SF,K+ and Ca2+ on the gelation time,and the structural changes of Ap-SF in sol-gel transformation were studied.The results indicated that the gelation time of the Ap-SF aqueous solution decreased with the increase of the Ap-SF concentration and environmental temperature.The sol-gel transformation of Ap-SF was much more rapid than that of Bombyx mori silk fibroin under the same conditions.The Ap-SF was sensitive to changes in the concentration of Ca2+ and K+.Upon gelation,the random coil structure of the Ap-SF was significantly transformed into the β-sheet structure.
