Developments in Pressurized Gyration for the Mass Production of Polymeric Fibers

In this invited feature article, the invention of pressurized gyration in 2013 and its subsequent development into sister processes such as pressurized melt gyration, infusion gyration, and pressure‐coupled infusion gyration is elucidated. The fundamentals of these processes are discussed, elucidating how these novel methods can be used to facilitate mass production of polymeric fibers and other morphologies. The effects of the main system parameters: rotational speed and gas pressure, are discussed along with the influence of solution parameters such as viscosity and polymer chain entanglement. The effect of flow of material into the gyrator in infused gyration is also illustrated. Examples of many polymers that have been subjected to these processes are discussed and the applications of resulting products are illustrated under several different research themes such as, tissue engineering, drug delivery, diagnostics, hydrogels, filtration, and wound healing.     

蚕丝素蛋白及其应用

阐述了丝素蛋白的组成、结构、性质和制备方法 ,及其综合利用现状。丝素作为一种天然蛋白质在医学和食品等行业中的应用开发研究具有深远的意义。     

再生蚕丝蛋白纤维的染色性能研究

主要研究染料种类、染料质量分数、氯化钠质量浓度、染色时间、染色温度等5个因素对再生蚕丝蛋白纤维上染率的影响,分析了再生蚕丝蛋白纤维的染色性能.结果表明:对纤维素纤维染色性能较好的染料对再生蚕丝蛋白纤维也有很好的染色性能.运用直接染料对再生蚕丝蛋白纤维进行染色,得到的最佳工艺为:染料质量分数1％ (omf)、氯化钠质量浓度12 g/L、染色温度85℃、染色时间50 min.     

Fabrication of Nanoscale Patternable Films of Silk Fibroin Using Benign Solvents

The silk protein fibroin is a wondrous biopolymer widely used to form structures that interface with biological entities. In addition to tissue scaffolds, sponges, and films, biochemically modified fibroins can be used in conjunction with techniques such as photolithography and soft lithography to expand their repertoire for micro‐ and nanofabricated systems. To date, the use of hexafluoro‐2‐isopropanol (HFIP) has been prevalent as a solvent for fibroin and fibroin “resists.” However, high volatility, toxicity, cost, and need for specialized disposal render the necessity for alternative solvents. Additionally, for applications such as in optics and bioelectronics, smooth, thin (≈100 nm and below) fibroin films are a prerequisite, which are not easily achieved using HFIP. Here, the use of formic acid (FA) as a sustainable solvent is presented for silk fibroin and fibroin “resist” materials, specifically for micro‐ and nanoscale applications. The reproducible formation and characterization of stable thin films of high homogeneity, smoothness, and optical transparency are demonstrated. Critically, these films can be used for high‐resolution photopatterning of proteins using benchtop lithographic techniques. The study indicates that FA is a relatively benign and optimal solvent for forming smooth, thin films, and microscale architectures for the fabrication of next generation silk‐based optical devices.

     

Enhancement of Interlaminar Fracture Toughness of Carbon Fiber/Epoxy Composites Using Silk Fibroin Electrospun Nanofibers

In this article, the effect of silk fibroin nanofibers as a toughening agent of carbon fiber/fabric-reinforced epoxy composites is experimentally investigated. The composites showed up to 30% improvement in Mode II fracture toughness at 0.1 wt% of silk fibroin nanofibers content. The scanning electron microscopy observation revealed that the fracture surface of silk fibroin nanofibers modified carbon fiber/fabric-reinforced epoxy composites appearance of the broken fiber and the ductile-like matrix cracks showed a good adhesion between matrix resin and carbon fibers, which are reasons for the enhanced mode II interlaminar fracture toughness.     

Self‐Expansion Behavior of Silk Fibroin Film

Summary: Silk fibroin cast film was prepared using a ternary solvent system of CaCl₂/CH₃CH₂OH/H₂O (1/2/8 in mole ratio). A drying temperature at casting influenced crystal structure of fibroin. When a drying temperature was set lower than 9 °C, the cast film became amorphous. When a drying temperature was set higher than 40 °C, a fibroin film of silk‐II structure was obtained. In order to produce a fibroin film of silk‐I structure, a preferable temperature range was from 20 to 26 °C. The crystal transformation from random coil structure into silk‐I could be made through exposure of an amorphous film to water vapor. As for the crystal transformation from silk‐I into silk‐II, the treatment with a glycerin solution was effective. In the course of the treatment a film showed self‐thinning and self‐expanding. The expansion ratio exceeded 40% at maximum. The film produced accompanying self‐expansion was ductile in nature.

The apparent self‐expansion percentage as a function of initial thickness of the film. The ductility of the film was classified into four stages from the observation of recovery behavior after folding: ?, very soft; ?, soft; ?, middle; ?, hard (see Figure 5 ).     

再生丝素蛋白水溶液流变行为的研究

根据蚕体内丝素蛋白浓度的变化,研究了相应条件下再生丝素蛋白浓溶液的流动曲线,探讨了流变行 为中丝素蛋白分子的构象变化,并用拉曼光谱对应力作用下再生丝素蛋白分子的构象变化进一步作了讨论。     

凝固条件对纤维素/丝素蛋白纤维相形态及性能的影响

蛋白质纤维具有光滑柔顺、透气吸湿等优点,然而天然蛋白纤维产量有限。再生蛋白纤维的制备通常采用与其它成纤高分子接枝或共混的方法,有利于提高再生蛋白纤维的断裂强度。选用同为天然高分子的纤维素为基体,以共溶剂溶解纤维素与蛋白质,进而纺丝成形制得力学性能满足要求的纤维素/丝素蛋白共混纤维。为了探究凝固剂组成对纤维素/丝素蛋白共混纤维相形态及性能的影响,选用水、乙醇、乙醇/1-丁基-3-甲基咪唑氯盐([BMIM]Cl)等作为凝固剂。研究发现:乙醇作为凝固剂时,纤维素与丝素蛋白能很好地同时凝固;而当在乙醇凝固浴中加入适量的[BMIM]Cl径向均匀分散。通过对凝固剂组成的调控能有效提升纤维的力学强度。     

Ultrasound Sonication Effects on Silk Fibroin Protein

The utilization of silk fibroin protein (SFP) in the field of biomaterials and tissue engineering plays an important role due to its promising mechanical, biological, and processing properties. In the present study, SFP solutions were exposed to ultrasound sonication to assess impact on molecular weight (Mw), sol–gel transition behavior, and physico‐chemical properties. The Mw of SFP was significantly reduced with sonication, determined by sodium dodecyl sulfate polyacrylamide gels (SDS–PAGE) gel electrophoresis. Sol–gel transitions were observed as SFP assembled to form a reversible SFP gel network at different concentrations and sonication time with the formation of a β‐sheet‐rich conformation in the gel state. The conformational changes and morphological properties were correlated over a range of SFP concentrations by circular dichroism (CD), UV spectroscopy, swelling and attenuated total reflectance fourier transformed infrared spectroscopy (ATR‐FTIR).

     

再生丝素蛋白/羟基磷灰石多孔复合材料的制备

再生丝素蛋白具有良好的生物相容性,羟基磷灰石同时还具有成骨诱导性。通过将再生丝素蛋白制备形成丝素蛋白多孔材料,并在37℃下将其浸渍于模拟体液中可以制备再生丝素蛋白/羟基磷灰石多孔复合材料。扫描电镜研究发现在再生丝素蛋白多孔材料的孔隙中羟基磷灰石由针状晶体聚集而成,红外光谱和XRD等表征表明复合材料中羟基磷灰石以羰基取代的羟基磷灰石存在。制备的再生丝素蛋白/羟基磷灰石多孔材料有望作为骨组织修复材料使用。     

静电纺再生丝素纳米纤维的结构与性能

静电纺丝获得的丝素纳米级纤维可作为细胞培养支架,用于纺丝工艺及后处理能改变丝素微细结构,影响其水溶性和力学性能。本文采用XRD、FTIR、固态13CNMR和DSC研究了不同工艺下丝素纳米纤维及经甲醇处理后的微细结构,比较了不同微细结构下的水溶性和力学性能。结果表明,电纺丝的微细结构受纺丝工艺影响,高电压、纺丝液中丝素质量分数大时纺得的电纺丝结晶度高,经甲醇处理后,β化程度提高;w(丝素)=11%、15%时制备的电纺丝断裂强度分别为8.5、11.9 cN/mm;w(丝素)=11%、19%,水溶性由51.2%下降到43.3%;w(丝素)=19%、电压32 kV制得的电纺丝甲醇处理前后水溶性从43.3%下降到6.6%,说明丝素纳米纤维结晶度提高,强度增加、水溶性下降,满足了细胞支架的要求。     

丝素共混膜在化妆品保湿效果评价中的应用初探

利用皮肤水分含量测试仪和水分散失测定仪,对添加不同质量分数甘油的保湿化妆品作用前后丝素共混膜的水分含量值（MMV）和经表皮水分散失值（TEWL）进行测定,以人体试验为参比,创造性地探索丝素共混膜在化妆品保湿效果评价中的应用价值,并对保湿类化妆品中保湿剂的最佳添加量做出指导。结果发现,丝素共混膜模拟体系的试验结果和人体试验具有相似的趋势,以其作为化妆品保湿效果评价的人体替代试验具有一定的可能性。     

丝素/羧甲基壳聚糖共混膜的结构与性能

利用丝素(SF)与羧甲基壳聚糖(CMCS)共混制取不同比例的SF/CMCS共混膜。研究了CMCS诱导的丝素构象转变行为,测试了共混膜的吸湿性、透湿性和保水性。当CMCS的质量分数为5%时,共混膜中丝素的构象以β-折叠为主;当CMCS的质量分数为10%时,共混膜中丝素的构象由β-折叠向α-螺旋发生转变;当CMCS的质量分数达到15%时,共混膜中丝素的构象向无规卷曲发生转变。当CMCS质量分数小于15%时,共混膜中SF与CMCS具有良好的相容性,溶胀度较小,吸湿性随CMCS含量的增加而迅速降低。     

蚕丝蛋白开发利用的研究进展

较为全面地综述了最近几十年国内外关于蚕丝蛋白的组成、性能,介绍了蚕丝新用途和利用原理,蚕丝脱胶精炼方法,以及蚕丝在化妆品、医药、固定化酶载体材料、食品、再生丝和涂膜化纤表面等方面的应用和研究进展。     

丝素蛋白/聚丙烯酸共混膜仿生合成羟基磷灰石

将丝素蛋白(SF)与聚丙烯酸(PAA)共混,制备丝素蛋白/聚丙烯酸(SF/PAA)共混膜;然后将此共混膜进行改性及矿化处理后,放置于(37±0.5)℃人体仿生液中24h,诱导合成丝素蛋白/羟基磷灰石(SF/HA)复合材料.利用傅里叶红外(FTIR)、X-射线衍射(XRD)、环境扫描电镜(ESEM)以及X射线能谱(EDX...     

A Fast and Reliable Process to Fabricate Regenerated Silk Fibroin Solution from Degummed Silk in 4 Hours

Silk fibroin has a high potential for use in several approaches for technological and biomedical applications. However, industrial production has been difficult to date due to the lengthy manufacturing process. Thus, this work investigates a novel procedure for the isolation of non-degraded regenerated silk fibroin that significantly reduces the processing time from 52 h for the standard methods to only 4 h. The replacement of the standard degumming protocol by repeated short-term microwave treatments enabled the generation of non-degraded degummed silk fibroin. Subsequently, a ZnCl₂ solution was used to completely solubilize the degummed fibroin at only 45 °C with an incubation time of only 1 h. Desalting was performed by gel filtration. Based on these modifications, it was possible to generate a cytocompatible aqueous silk fibroin solution from degummed silk within only 4 h, thus shortening the total process time by 48 h without degrading the quality of the isolated silk fibroin solution.     

柞蚕丝丝素/壳聚糖共混体系的静电纺丝研究

利用六氟异丙醇和三氟乙酸为溶剂,通过静电纺丝制备了不同共混比的柞蚕丝丝素(TSF)/壳聚糖(CS)纳米纤维。研究了TSF/CS共混比对纺丝液黏度、电导率和纤维形貌的影响。结果表明,TSF/CS共混液的电导率随CS含量的增加而增加;随着CS含量的增加(≤15%),共混液的黏度增加缓慢,纤维由转曲的扁平带状逐渐变为圆柱形且直径逐渐降低;当CS含量超过15%时,共混液的黏度随CS含量的增加而显著增大,纤维出现粗细两极分化现象。     

棉织物丝素/TiO_2生态功能整理

用丝素蛋白整理棉织物,研究丝素蛋白降解时间及浓度对整理后棉织物性能的影响,确定最佳的丝素降解时间和浓度。在此基础上与TiO2复配,研究整理剂中TiO2含量对棉织物性能和结构的影响。结果表明:最佳丝素蛋白降解时间为120min,丝素浓度(质量分数)为1.63%;此时将丝素与TiO2复配,当TiO2质量分数为0.35%时,可使织物折皱回复角比纯丝素整理提高8.68%,紫外防护系数达到42.9,抗紫外性能达到二级。X射线衍射分析表明,丝素蛋白整理可降低棉纤维的结晶度,并使棉纤维由纤维素Ⅰ向纤维素Ⅱ转变,而TiO2整理可提高棉纤维的结晶度。     

Electroactive Silk Fibroin Films for Electrochemically Enhanced Delivery of Drugs

Biomaterials capable of controlling the delivery of drugs have the potential to treat a variety of conditions. Herein, the preparation of electrically conductive silk fibroin film‐based drug delivery devices is described. Casting aqueous solutions of Bombyx mori silk fibroin, followed by drying and annealing to impart β‐sheets to the silk fibroin, assure that the materials are stable for further processing in water; and the silk fibroin films are rendered conductive by generating an interpenetrating network of a copolymer of pyrrole and 3‐amino‐4‐hydroxybenzenesulfonic acid in the silk fibroin matrix (characterized by a variety of techniques including circular dichroism, Fourier‐transform infrared spectroscopy, nuclear magnetic resonance, Raman spectroscopy, resistance measurements, scanning electron microscopy‐energy dispersive X‐ray spectroscopy, thermogravimetric analysis, X‐ray diffraction, and X‐ray photoelectron spectroscopy). Fibroblasts adhere on the surface of the biomaterials (viability assessed using an (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay and visualized using a confocal microscope), and a fluorescently labeled drug (Texas‐Red Gentamicin) can be loaded electrochemically and released (µg cm^?2 quantities) in response to the application of an electrical stimulus.     

Fibroin membrane preparation and stabilization by polyethylene glycol diglycidyl ether

Membranes prepared by drying aqueous Bombyx mori silk fibroin (SF) solution and modified silk fibroin (MSF) solutions, prepared by adding the low molecular weight crosslinking agent, polyethylene glycol diglycidyl ether (PEGDE) MW 526, 0–10% w/w, were investigated by Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, and UV–vis spectroscopy. Weight gain in aqueous solutions and their mechanical properties (tensile strength, elongation, and Young's modulus) were then characterized. SEM measurements revealed greater porosity in MSF membranes. IR spectra showed transformation from the largely α‐helical/random coil structures in SF membranes to predominantly β‐sheet in MSF membranes. Results from UV–vis spectroscopy showed that the MSF membranes were largely insoluble within the pH range of 4–10. Water absorbability of the MSF membranes improved with increasing the amounts of cross‐linker, up to 4%. The MSF membranes showed greater pliability and tenacity, but lower tensile strength, with increasing PEGDE concentrations. In the wet condition, PEGDE levels up to 4% can improve both tensile strength and tenacity of the MSF membrane, but higher levels (up to 10%) did not significantly change these properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008