Fine Structure of Regenerated Silk Fibroin Solids

ＩｎｔｒｏｄｕｃｔｉｏｎＳｉｌｋｆｉｂｒｏｉｎ (Ｂｏｍｂｙｘｍｏｒｉ)ｉｓｔｈｅｐｏｌｙｍｅｒｗｉｔｈｔｗｏｋｉｎｄｓｏｆｃｒｙｓｔａｌｓｔｒｕｃｔｕｒｅ,ｓｉｌｋⅠａｎｄｓｉｌｋⅡ[1,2 ] .ＴｈｅｓｐａｃｅｃｏｎｆｏｒｍａｔｉｏｎｏｆｓｉｌｋⅠｔａｋｅｓｏｎｔｈｅｓｈａｐｅｏｆｃｒｏｏｋｅｄｈａｎｄｌｅ ,ｔｈｅｉｎｔｅｒｍｅｄｉａｔｅｆｏｒｍｂｅｔｗｅｅｎα ｓｐｉｒａｌｓｔｒｕｃｔｕｒｅａｎｄβ ｆｏｌｄｅｄｓｔｒｕｃｔｕｒｅ ,ａｎｄｔｈａｔｏｆｓｉｌｋⅡｉｓａｎｔｉ ｐａｒａｌｌｅｌβ ｆｏｌｄｅ…     

家蚕丝素溶液的粘弹性研究

采用Coucttc流变仪对家蚕丝素溶液的粘弹性进行研究。对于生丝丝素溶液,当丝素浓度较稀时(如4w/v％),溶液表现出牛顿流动行为;当丝素浓度较高时(如25W/V％),溶液表现出复杂的非牛顿流动行为。成烈的家蚕丝腺中的丝素,在剪切速率大于0.25s~1时,能引起纤维化。     

Mechanism of silk processing in insects and spiders

Silk spinning by insects and spiders leads to the formation of fibres that exhibit high strength and toughness. The lack of understanding of the protein processing in silk glands has prevented the recapitulation of these properties in vitro from reconstituted or genetically engineered silks. Here we report the identification of emulsion formation and micellar structures from aqueous solutions of reconstituted silkworm silk fibroin as a first step in the process to control water and protein-protein interactions. The sizes (100-200 nm diameter) of these structures could be predicted from hydrophobicity plots of silk protein primary sequence. These micelles subsequently aggregated into larger 'globules' and gel-like states as the concentration of silk fibroin increased, while maintaining solubility owing to the hydrophilic regions of the protein interspersed among the larger hydrophobic regions. Upon physical shearing or stretching structural transitions, increased birefringence and morphological alignment were demonstrated, indicating that this process mimics the behaviour of similar native silk proteins in vivo. Final morphological features of these silk materials are similar to those observed in native silkworm fibres.     

Nanoscale control of silks for regular hydroxyapatite formation

The control of nanoparticle shape is still a challenge for different hydroxyapatite (HA) preparation ways.In the present study,silk fibroin with regular nanostructures was firstly prepared and then emp...     

明胶/丝素共混多孔膜的制备

采用冷冻干燥法制备明胶与家蚕丝素的共混多孔蛋白膜，探讨了交联剂用量，共混比例及冷冻温度对膜结构和性能的影响，指出戊二醛对共混多膜具有明显的交联作用，膜内丝素与明胶的相容性较好，蛋白质的结构以无定形为主，通过与明胶共混，能够改善多孔丝素膜的拉伸性能。     

天然丝素制备三维多孔支架

研究盐沥滤法制备三维多孔丝素支架,在丝素多孔支架上培养人成骨肉瘤细胞、成纤维细胞及肝细胞.研究材料的细胞相容性,发现多种动物细胞在盐沥滤法所制备的丝素多孔支架材料上能够很好地黏附和增殖.通过调整丝素水溶液的浓度、溶解丝素溶剂体系、NaCl添加量和NaCl粒径,制备出结构和性质可以调控的三维支架.该结果为丝素多孔支架材料的制备提供了新的研究思路和方法.     

多孔柞蚕丝素支架的制备及其在药物缓释中的应用

采用冷冻干燥法制备了多孔柞蚕丝素支架,分析了丝素溶液浓度与支架孔径、孔隙率之间的关系,并研究了多孔柞蚕丝素支架负载5-氟尿嘧啶的缓释性能.研究表明,当丝素浓度较低时,支架中的孔洞分布较为均匀,孔径和孔隙率也较大,而随着丝素溶液浓度增大,支架的孔径和孔隙率逐渐减小;支架的药物释放过程可分为快速释放和缓慢释放两个阶段.     

丝素在NMMO·H2O中的溶解及溶液流变性能的研究

探讨了丝素在N-甲基吗啉-N-氧化物一水合物(NMMO.H2O)中的溶解行为,结果发现:天然蚕丝纤维脱胶后得到的丝纤维可以直接溶解在NMMO.H2O中,但是很难得到高于10%浓度的溶液,因而无法用于纺丝.而由再生丝素水溶液制得的再生丝素膜则易于溶解在NMMO.H2O中,并可以得到浓度高达25%的再生丝素/NMMO.H2O溶液,在上述研究的基础上,本文还对再生丝素/NMMO.H2O的流变行为进行了初步研究.     

稀土固着丝胶增重真丝纤维的结构变化

用稀土金属离子通过形成配位结合来固着丝胶，制备了不同增重率的丝纤维，研究了增重丝纤维结构变化。与未增重丝纤维相比，增重丝纤维的纵向形态和截面形态发生了变化，增重丝纤维中氮元素和碳元素的含量呈下降趋势，增重丝纤维中极性氨基酸含量增加，增重丝纤维的结晶度随着增重率的增加而下降，增重丝纤维热分解峰顶温度变化不明显。     

丝素在生物医学领域中的应用

讨论了丝素（silk fibroin,SF)与生物医学领域应用相关的基本性质，以及在生物分析及药物缓释载体，人工器官及组织工程支撑体材料中的应用现状，结论认为：丝素具有固化结晶方式的多样化。易于保持高度生物亲和性以及形成特殊的多孔性网状结构。丝素还具有优良的成膜特性，并且通过与其它一些天然高分子材料的复合与化学改性，可以进一步改善其物理性能，从而适宜于构建新型药物载体与人工器官，同时，针对丝素蛋白在体的生物相容性，在体降解特性方面存在的问题，认为其在体变化机制不仅取决于与之接触体液的化学构成，也与温度，力学环境等生物物理因素有关，因此其在体变化机制是生物力学与生物流变学的因素与生物化学因素协同控制的。     

Preparation and Characterization of Silk Fibroin Aerogel

Silk protein fibroin,as a biomedical material,has good biocompatibility,biodegradability,regulation and excellent physical and chemical properties. In this work,a low density porous silk fibroin material is prepared from fibroin solution by high-speed shearing with impeller. By adjusting shear rate of the stirrer,silk fibroin aerogel with different sizes of the aperture is prepared. In general, this aerogel has small porosity, uniform pores, good mechanical properties and slow rate of degradation. It is observed that increasing the shear rate results in higher porosity of aerogel,while the diameter of the aerogel becomes smaller. This silk aerogel may offer a new option as biomaterial for the tissue engineering application based on the information on the structural behaviors.     

Physico-Chemical Properties of a Water-Insoluble Silk Fibroin Film

The conventional silk fibroin(SF)films obtained by casting from SF aqueous solution are amorphous,and easily dissolved in water.This defect limits the practical use of SF films in biomedical field.A new water-insoluble silk fibroin film(an SF-FA film)could be simply prepared by casting from SF formic acid solution.The physical properties and moisture permeability of SF-FA films were examined.The results show that the SF-FA film swollen in water exhibits outstanding pliability.The weight loss of SF-FA films ...     

IMPROVEMENT OF WET-CREASE RECOVERY PROPERTIES OF SILK FABRICS TREATED WITH EPOXIDES

Silk fabrics is finished with epoxide TDEA or TDEB. By the determination of washing fastness, DSC, IR spectrum and amino acid contents tests, TDEA or TDEB is confirmed to react with silk fibroin. By means of tests of silk fibroin swelling and solubility in some solvents, crosslinking reactions between TDEA or TDEB and silk fibroin arc further proved, which is obviously responsible to the increase of wet-crease recovery of silk fabrics finished with epoxide TDEA or TDEB.     

丝素改性聚氨酯膜的物理性质及其细胞相容性

用丝素蛋白或丝素肽表面改性的聚氨酯膜表现出良好的柔韧性，它能够克服丝素膜刚而脆的弱点；由水分散型聚氨酯制备的改性膜的透气性高于疏水性聚氨酯膜；细胞培养实验结果表明：经丝素蛋白或丝素肽改性后，聚氨酯膜的生物相容性明显提高且处理效果是稳定的。     

丝素蛋白在组织工程中的应用

丝素蛋白作为一种具有优良生物相容性的天然高分子材料在生物医用领域有着广泛的应用，着重阐述了丝素蛋白在组织工程领域中应用研究的最新进展。     

高含量再生丝素蛋白水溶液的热性能研究

用差示扫描量热仪(DSC),对不同含量的再生丝素蛋白水溶液(质量分数为12%~42%),以及同一含量不同剪切速率(1 000 s-1和2 000 s-1)下溶液热性能的变化进行了对比研究。结果表明,随着含量的增大,再生丝素蛋白水溶液发生相转变的温度逐渐降低;同样,经剪切后的溶液发生相转变的温度均向低温漂移,且随着剪切作用的加强,向低温的漂移越明显。试验表明,丝素水溶液含量的增加和剪切作用可加速溶液从无规线团或α-螺旋向β-折叠构象的转变速度,且随着剪切速率的提高,构象转变的速度也加快。     

切变速度和Ca~(2+)对再生丝素蛋白溶液构象转变的影响

采用偏光显微镜和拉曼光谱研究了切变速度和Ca2+对再生丝素蛋白水溶液构象转变的影响.结果表明:切变速度和Ca2+是影响再生丝素蛋白溶液性质的两个主要因素,对于同一再生溶液,切变速度增大,溶液中丝素蛋白分子沿切变方向的有序排列也随之增加,丝素溶液更容易从无规线团或α-螺旋向β-折叠转变,并且转变的程度随着剪切速度的增加而加强;透析溶液中Ca2+含量增加,则样品出现偏光现象的临界切变速度有所降低.拉曼光谱显示丝素蛋白分子构象由SilkⅠ向SilkⅡ转变.     

预处理对丝素促进293T细胞生长的影响

采用多种处理方法对丝素进行预处理,探讨其作为支架对293T细胞生长的促进作用．正交实验结果显示：以脱胶方式和包埋方法对结果的影响明显,并有统计学意义（P≤0．01）;在经胰蛋白酶脱胶、盐酸作用、以壳聚糖／聚乙二醇包埋的双股丝素蛋白纤维支架上,293T细胞数最多;在经胰蛋白酶脱胶、氢氧化钠作用、以壳聚糖／聚乙二醇包埋的3股丝素蛋白纤维支架细胞上,293T细胞活性达到最大．处理后的支架能使293T细胞很好地生长增殖,细胞呈球状体、集落性附着在丝素蛋白纤维上．     

A New Catalyst in the Crease Recovery Finishing of Silk Fabrics with Epoxide

IntroductionSilk, among natural and synthetic fibers, is one of themost favored textile materials because of its excellent wearcomfort and elegant appearance. Because of theseproperties, it is regarded as a luxury material. Silk has acombination of many desirable properties. Unfortunately,its major weakness, a very low wet resiliency, causesconsiderable inconvenience in the use of silk textiles. Sincethe beginning of 1970 s, much research has been carriedout, ma…     

辣根过氧化物酶在石墨电极上的固定化及其对H_2O_2的响应

基础电极的选择和酶、抗体、DNA等生物活性分子的固定化方法都是影响生物传感器性能的关键因素.以石墨电极(GE)为基础电极,基于辣根过氧化物酶(HRP)对H2O2氧化邻苯二胺(OPD)生成2,3-二氨基吩嗪(DAP)反应体系的高效催化作用,研究了HRP固定化技术.分别利用再生丝素、聚乙二醇、壳聚糖包埋固定HRP,并以HRP修饰GE为指示电极,通过电位法测定H2O2浓度,对不同的固定化方法进行评价.结果表明,利用再生丝素包埋法制备的HRP/GE电极对H2O2具有更好响应性能,其工作曲线斜率为54.97,检测下限为8.82×10-8 mol.dm-3,线性范围为3.53×10-7～8.82×10-4 mol.dm-3.所提出的HRP/GE具有制备简单、成本低廉、响应快、灵敏度高等优良性能,具有较好的应用前景.