从天然动物丝到丝蛋白基材料的研究

作为具有优异综合力学性能的天然蛋白质纤维,丰产的动物丝特别是蚕丝长期伴随着人们的日常生活,近十余年来,各种具有特色的功能性丝蛋白基材料更是层出不穷.但在探索动物丝和丝蛋白基材料的过程中,动物丝纤维是经由蚕或蜘蛛等动物的纺器而纺制得到的简单事实往往被忽视;换言之,动物丝实际上是动物对丝蛋白进行体内“加工”后的产物,也是丝蛋白基材料中的一种.因此,天然动物丝中独特的各等级间构效关系与丝蛋白基材料的构效关系之间并不存在着必然的传承效应.本文着重介绍了我们在对动物丝和丝蛋白基材料探索中的经验和体会,即在强调以丝蛋白分子链结构与性能及其之间的关系为研究重点的基础上,从比较和发掘各种天然动物丝的特性入手,进而了解丝蛋白分子链在本体和溶液中的行为,并通过对动物丝蛋白分子链聚集态结构的调控,以达到设计制备一系列多形貌和多功能的动物丝蛋白基材料的目的.

The Investigation from Animal Silks to Silk Protein-based Materials

Animal silk,especially silkworm silk,which has a long history and good practical performance,is one of the outstanding representatives for natural biomaterials.Although both of silkworm silk and spider dragline silk(abbr.as spider silk below)are formed by natural proteins with the similar molecular weight as well as amino acid composition,the comprehensive mechanical properties(especial the toughness)of the silkworm cocoon silk are much worse than those of spider silk,Previously,it was reasonably thought that such contrast on the mechanical properties of the silks was caused by the different amino acid sequences of silkworm silk protein(named as fibroin)and spider silk protein(named as spidorin).Nevertheless,the properties of the silk fibers formed by these recombinant spidroins still show less competitive with those of natural animal silks(including silkworm silk)in terms of mechanical properties besides the extremely high cost for the production so far.Indeed,it must be recognized that animal silk is naturally processed and can be directly used as a fiber.Therefore,the reasonable routine for basic research and practical development of animal silk and silk protein-based materials should be(1)exploration of intrinsic properties and investigation of multi angle/multi-level structure-property relationships of natural silk fiber;(2)acquisition/regeneration of silk protein and the research on its molecular chain behavior;(3)according to the understanding on its molecular chain behavior based on the multi-level structure-property relationship of regenerated silk protein molecular chain,endowing silk protein based-materials with various sharps,morphologies as well as functions,especially those non-fiber materials,in order to achieve diversified applications.Based on a few of achievements in our group,this article reviewed the way mentioned above regarding the investigation on animal silks and fibroin-based materials,while emphasized that the hierarchical structure and structure-function relationship in the natural fiber could not spontaneously extend to silk proteinbased materials.We also expected this concept would lead the research on the preparation of animal silk proteins represented non-physiologically active biomacromolecule-based materials with different morphologies and sitespecific functions.