再生丝素纤维的力学性能及其生物可降解特征

背景:再生丝素纤维溶解过程中丝素蛋白的分子量不可避免地会产生一定的降解,致使再生丝素纤维至今未进入实用阶段。目的:获得生物可降解的再生丝素纤维。设计:单一样本实验。单位:苏州大学材料工程学院丝绸工程江苏省重点实验室。材料:下脚蚕丝由苏州丝绸进出口公司提供。方法:2003-01/2004-12在苏州大学材料工程学院丝绸工程江苏省重点实验室完成。通过控制废弃天然丝素纤维在中性盐溶解时分子量的变化、湿法纺丝工艺条件和牵伸倍率方法纺制具有一定力学性能和生物可降解的再生丝素纤维。具体步骤:①制备丝素。②制备纺丝液。③再生丝素纤维湿法纺丝。④采用十二烷基硫酸钠-聚丙稀酰胺凝胶电泳法测定溴化锂溶解后丝素溶液的分子量。⑤测定丝素纤维的结晶度和取向度。⑥测定再生丝素纤维的力学性能。⑦测定丝素纤维的体外酶降解率。主要观察指标:①经溴化锂溶解的丝素蛋白的相对分子质量。②X射线衍射结果。③再生丝素纤维的体外酶降解率。结果:①经溴化锂溶解后,丝素蛋白纺丝液的分子量主要分布在10万以下。②在再生丝素纤维湿法纺丝的凝固、牵伸过程中,丝素的构象从无规卷曲转变为分子链中β-折叠和无规卷曲/α-螺旋构象共存。③用放线菌酶对六氟异丙醇法纺制的再生丝素纤维的体外酶降解实验表明,再生丝素纤维其30d的降解率为37.16%,天然丝素纤维的30d的降解率为10.70%。结论:通过控制再生丝素纺丝液分子量、湿法纺丝工艺条件和牵伸倍率方法,可纺制具有一定力学性能和生物可降解的再生丝素纤维。

Mechanical and biodegradable properties of regenerated fibroin fibers

BACKGROUND: The molecular weight of fibroin is inevitably reduced in the course of the dissolution of regenerated fibroin fiber, and this is why we have not entered the stage of the practical application of the regenerated fibroin fiber till now.OBJECTIVE: To obtain biodegradable regenerated fibroin fiber.DESIGN: A single sample experiment.SETTING: Jiangsu Provincial Key Laboratory of Silk Project of Material Engineering College of Soochow University.MATERIALS: Leftover silk pieces were provided by Suzhou Silk Import & Export Corp.METHODS: This study was performed at Jiangsu Provincial Key Laboratory of Silk Project of Material Engineering College of Suzhou University between January 2003 and December 2004. By controlling the molecular of abandoned natural fibroin fiber during neutral salt dissolution process, wet spinning technique and draft method were applied to spin regenerated fibroin fibers that have certain mechanical and biodegradable properties.The specific procedure is as follows: ①fibroin preparations. ② Spinning solution preparations. ③ Regenerated fibroin fibers were spun with wet spinning method. ④Sodium lauryl sulphate-polyacrylamide gel electrophoresis method was used to detect the molecular weight of LiBr dissolved fibroin solution. ⑤To detect the crystallinity and orientation of fibroin fibers. ⑥ To detect the mechanic properties of regenerated fibroin fibers. ⑦ To detect the in vitro enzyme degradation rate of fibroin fibers.MAIN OUTCOME MEASURES: ①The relative molecular weight of LiBr dissolved silk fibroin. ② Result of X-Ray diffraction. ③The in vitro enzyme degradation rate of regenerated fibroin fibers.RESULTS: ①After LiBr dissolution, the molecular weight of fibroin spinning solution was mainly below 100 000. ②During the coagulation and pulling process of regenerated fibroin fiber wet spinning, fibroin fiber conformation changed from random convolution to the co-existence of β-folding and random coi1/α-spiral conformation in molecular chain. ③ Actinozyme was used to assess the in vitro enzyme degradation rate of hexafluoroisopropanol spun regenerated silk fibroin, and the 30 day-degradation rate of regenerated fibroin fibers was 37.16%, compared with 10.70% of natural fibroin fiber.CONCLUSION: Wet spinning technique and draft method can be used to spin regenerated fibroin fibers possessing certain mechanical and biodegradable properties by controlling the molecular weight of abandoned natural fibroin fibers during neutral salt dissolution process.