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。     

丝素/羧甲基壳聚糖共混膜的结构性能探讨

将含有甘油和戊二醛的丝素与羧甲基壳聚糖按一定比例混合,制得丝素/羧甲基壳聚糖共混膜,对共混膜的结构与性能进行了探讨。结果表明:随着羧甲基壳聚糖含量的增加,共混膜的透气率增大,加入交联剂戊二醛有效地改善了共混膜的力学性能,但其透气率有所降低;当丝素与羧甲基壳聚糖的质量比为4/1时,共混膜的断裂强度最大,力学性能较好,共混膜相容性较好,其断面光滑、致密。制备丝素/羧甲基壳聚糖共混膜的较佳条件为:丝素中的甘油质量分数为15%,戊二醛质量分数为0.075%,丝素与羧甲基壳聚糖质量比为4/1。     

羧甲基壳聚糖/聚(N-异丙基丙烯酰胺)半互穿网络水凝胶的制备及吸附重金属离子

以N-异丙基丙烯酰胺和羧甲基壳聚糖(CMCS)为原料成功制备了羧甲基壳聚糖/聚(N-异丙基丙烯酰胺)半互穿网络水凝胶,通过扫描电镜(SEM)﹑测溶胀比对凝胶性能进行了表征。考察了羧甲基壳聚糖对于凝胶内部微观结构的影响及其对Fe3+吸附性能的变化。发现随着CMCS用量的增加,凝胶内部结构的孔状网络结构更为明显,水凝胶对Fe3+离子吸附能力增强。     

羧甲基壳聚糖及其纤维的制备及表征

用氯乙酸改性处理壳聚糖(CS)制备羧甲基壳聚糖(CMCS),采用湿法纺丝法制备CMCS纤维,考察了纺丝原液浓度、醋酸水溶液体积分数、凝固时间对CMCS纤维力学性能的影响;通过傅里叶变换红外光谱、X射线衍射以及热失重分析对CS,CMCS及其纤维进行表征。结果表明:CMCS发生了羧甲基取代,同时CMCS结晶度降低;CMCS纤维结构中含有结合水,热分解温度为270℃;纺丝原液CMCS的质量分数为50%,醋酸水溶液的体积分数为2%、凝固时间为12 min时,CMCS纤维的断裂强度达0.644 cN/dtex。     

羧甲基壳聚糖/氧化魔芋葡甘聚糖复合海绵的制备与性能评价

以羧甲基壳聚糖(CMCS)和氧化魔芋葡甘聚糖(OKGM)为原料,采用冷冻干燥法制备羧甲基壳聚糖/氧化魔芋葡甘聚糖(CMCS/OKGM)复合海绵,通过FTIR、~1HNMR、SEM等对其结构进行表征,通过吸水率、孔隙率、透气率、对NIH-3T3细胞增殖的影响、抗菌能力及急性全身毒性等测试来评价其性能。确定CMCS/OKGM复合海绵的最优制备工艺为:先采用高碘酸钠氧化制备OKGM,再按5∶5的体积比将质量浓度均为5%的CMCS溶液和OKGM溶液混合,加入2%的甘油作为塑化剂,冷冻干燥即得。CMCS/OKGM复合海绵具有良好的吸水率、孔隙率、透气率、抗菌活性、生物安全性且能促进表皮细胞增殖,是优良的医用慢性伤口敷料基础底料。     

壳聚糖对脆弱丝绸的加固保护初探

采用壳聚糖对脆弱丝绸进行加固探索试验,考察了加固剂壳聚糖的浓度、浸渍时间及软化剂的加入等因素对加固效果的影响,确定了最优工艺条件为壳聚糖含量为0.06%,加入软化剂A,浸渍时间为10 min,在此条件下试验所得加固试样手感柔软,断裂强度大幅度提高了;通过对加固前后的试样丝纤维的SEM形貌和红外光谱分析,结果显示壳聚糖对脆弱丝绸有加固保护的作用,且不改变脆弱丝绸的结构和性能。     

微波加热制备羧甲基壳聚糖的工艺及其产品对水果的保鲜效果

以壳聚糖(CTS)为主要原料,采用微波加热法将CTS与氯乙酸发生醚化改性反应,得到羧甲基壳聚糖(CMCS)。改性后CMCS与CTS相比,不仅水溶性增加,而且产品具有良好的成膜性。将CMCS产品溶解后,浸渍于浆果樱桃表面,使其在樱桃表面成膜,该膜不仅无毒无害,而且对身体具有保健作用。通过测试不同浓度的CMCS涂膜对樱桃的失水率的测定,结果表明,涂膜CMCS后的樱桃延长了保鲜期,在CMCS浓度为0.5%时,其涂膜对樱桃的保鲜效果最好。     

微波加热制备羧甲基壳聚糖的工艺及其产品对水果的保鲜效果

以壳聚糖(CTS)为主要原料,采用微波加热法将CTS与氯乙酸发生醚化改性反应,得到羧甲基壳聚糖(CMCS)。改性后CMCS与CTS相比,不仅水溶性增加,而且产品具有良好的成膜性。将CMCS产品溶解后,浸渍于浆果樱桃表面,使其在樱桃表面成膜,该膜不仅无毒无害,而且对身体具有保健作用。通过测试不同浓度的CMCS涂膜对樱桃的失水率的测定,结果表明,涂膜CMCS后的樱桃延长了保鲜期,在CMCS浓度为0.5%时,其涂膜对樱桃的保鲜效果最好。     

改性壳聚糖对处理污泥脱水性能影响的研究

研究了聚合氯化铝、壳聚糖和3种羧甲基壳聚糖（N-羧甲基壳聚糖、N，O-羧甲基壳聚糖和O-羧甲基壳聚糖）絮凝剂对污泥的脱水性能作用．实验结果表明．羧甲基壳聚糖作为絮凝剂对污泥进行脱水时．形成的絮体强度大．不易破碎．对污泥脱水的效果明显好于普通絮凝剂．在3种所研究的羧甲基壳聚糖中．     

两种纳米纤维素对老化文献纸张的加固性能研究

酸化老化文献纸张的脱酸和加固是近年来各图书馆、博物馆和档案馆等文献保护领域普遍关心的问题。采用棉花纳米纤维素晶须(CNC-C)和棉花纤维素纳米纤丝(CNF-C)两种纳米纤维素及其复配物对三种模拟老化文献纸张进行加固,测定加固前后的抗张强度、耐折度和撕裂度。结果表明:纤维素纳米纤丝(CNF-C)和纳米纤维素晶须(CNC-C)对老化纸张都有非常明显的加固效果;两种纳米纤维素复配加固效果优于单独使用,抗张强度最高增强103%,耐折次数最高提升9.8倍,撕裂度最高提升81%,加固效果明显好于常用的羧甲基纤维素。     

Structure and properties of silk fibroin/carboxymethyl chitosan blend films

The secondary structure of silk fibroin (SF) and the compatibility of the two components were associated with the carboxymethyl chitosan (CMCS) content in SF/CMCS blend films. A rather complete conformation transition of SF from random coil to β-sheet occurred after adding 5% CMCS into the SF film, and the blend film exhibited a high crystallinity and a good compatibility. The conformation of SF changed from β-sheet to α-helix when blending 10% CMCS. When the CMCS content was up to 15%, the conformation of SF in blend films showed a transformation from β-sheet to a random coil and their crystallinities decreased evidently; accordingly, there was a two-phase separation structure for the blend films containing 15% CMCS or more. However, the intermolecular interaction between the two polymers still existed in blend film with 15% CMCS or more. The blend films with 5–10% CMCS content showed the lower moisture absorption, swelling capacity, and solubility in water. These properties of blend films increased when adding CMCS more than 15%.     

Comparison of three-dimensional printing for fabricating silk fibroin-blended scaffolds

In this study, two types of scaffolds were fabricated by 3D printing. Morphology, physical properties, biochemical were evaluated. Cell morphology and distribution were observed. It was found that the silk fibroin/collagen (SF/C) scaffold-based material had significantly higher values than the silk fibroin/chitosan (SF/CS) scaffold-based material. Hematoxylin and eosin staining of the scaffolds revealed that the number of cells in the SF/C scaffold was higher. Cells grew well inside the SF/C scaffold as measured by scanning electron microscope. Reverse Transcriotion-Polymerase Chain Reaction (RT-PCR) and Western blot showed that type II collagen and Sox9 can be found in SF/C scaffold. Therefore, the SF/C scaffold exhibited better overall performance compared with the SF/CS scaffold.     

Preparation of Silk Fibroin/Carboxymethyl Chitosan Hydrogel under Low Voltage as a Wound Dressing

At present, silk fibroin (SF) hydrogel can be prepared by means of electrodeposition at 25 V in direct current (DC) mode. Reducing the applied voltage would provide benefits, including lower fabrication costs, less risk of high voltage shocks, and better stability of devices. Here, a simple but uncommon strategy for SF-based hydrogel preparation using 4 V in DC mode is discussed. SF was mixed and cross-linked with carboxymethyl chitosan (CMCS) through hydrogen bonding, then co-deposited on the graphite electrode. The thickness, mass, and shape of the SF/CMCS hydrogel were easily controlled by adjusting the electrodeposition parameters. Morphological characterization of the prepared hydrogel via SEM revealed a porous network within the fabricated hydrogel. This structure was due to intermolecular hydrogen bonding between SF and CMCS, according to the results of thermogravimetric analysis and rheological measurements. As a potential wound dressing, SF/CMCS hydrogel maintained a suitable moisture environment for wound healing and demonstrated distinct properties in terms of promoting the proliferation of HEK-293 cells and antibacterial activity against Escherichia coli and Staphylococcus aureus. Furthermore, histological studies were conducted on a full-thickness skin wound in rats covered with the SF/CMCS hydrogel, with results indicating that this hydrogel can promote wound re-epithelization and enhance granulation tissue formation. These results illustrate the feasibility of using the developed strategy for SF-based hydrogel fabrication in practice for wound dressing.     

Fabrication of Chitosan/Silk Fibroin Composite Nanofibers for Wound-dressing Applications

Chitosan, a naturally occurring polysaccharide with abundant resources, has been extensively exploited for various biomedical applications, typically as wound dressings owing to its unique biocompatibility, good biodegradability and excellent antibacterial properties. In this work, composite nanofibrous membranes of chitosan (CS) and silk fibroin (SF) were successfully fabricated by electrospinning. The morphology of electrospun blend nanofibers was observed by scanning electron microscopy (SEM) and the fiber diameters decreased with the increasing percentage of chitosan. Further, the mechanical test illustrated that the addition of silk fibroin enhanced the mechanical properties of CS/SF nanofibers. The antibacterial activities against Escherichia coli (Gram negative) and Staphylococcus aureus (Gram positive) were evaluated by the turbidity measurement method; and results suggest that the antibacterial effect of composite nanofibers varied on the type of bacteria. Furthermore, the biocompatibility of murine fibroblast on as-prepared nanofibrous membranes was investigated by hematoxylin and eosin (H&E) staining and MTT assays in vitro, and the membranes were found to promote the cell attachment and proliferation. These results suggest that as-prepared chitosan/silk fibroin (CS/SF) composite nanofibrous membranes could be a promising candidate for wound healing applications.     

3D mesoporous bioactive glass/silk/chitosan scaffolds and their compatibility with human adipose-derived stromal cells

Human adipose-derived stem/stromal cells (hASCs) have been popularly studied as cell-based therapy in the field of regenerative medicine due to their ability to differentiate into several cell types. In this study, in order to improve the mechanical strength and bioactivity of scaffolds for bone tissue engineering, three types of mesoporous bioactive glasses with different shapes and compositions were dispersed in the silk fibroin/chitosan (SF/CS)-based scaffolds, which were fabricated with a combination of freezing and lyophilization. The characteristic and physical properties of these composite scaffolds were evaluated. The biocompatibility was also assessed through hASCs in vitro tests. Both Alamar Blue® and Live/Dead assay® revealed that the spherical mesoporous bioactive glass doped scaffolds enhanced cell viability and proliferation. Furthermore, the addition of spherical mesoporous bioactive glass into SF/CS scaffolds encouraged hASC osteogenic differentiation as well. These results suggested that this composite scaffold can be applicable material for bone regeneration.     

Analyzing the interactions and miscibility of silk fibroin/mucin blends

Mucin, a glycoprotein with viscoelastic properties, and silk fibroin, a protein excreted from silkworms with properties of thermal and mechanical resistance, have been probed as building blocks in the design of biomaterials. Aiming to evaluate the interaction and miscibility between mucin and fibroin, we synthesized silk fibroin and mucin (SF/MU) blends for biomedical applications. The morphological analysis of the SF/MU blends showed the presence of two phases, suggesting a partial miscibility between the polymers. The degradation temperature of the SF/MU blends increased with an increase in the silk fibroin content, indicating that silk fibroin contributed to the thermal stability of the blends. The glass transition temperature of the SF/MU blends lay between the values of the pure polymers. The Fourier-transform infrared spectroscopy results pointed out that the interaction between fibroin and mucin occurred between the amine group of silk fibroin and mucin carboxyl and hydroxyl groups. The outcomes of this work provided essential information on the miscibility of the SF/MU blends. These findings will be critical for further studies with fibroin and mucin-based biomaterials, especially in mucoadhesive systems and wound healing applications.     

Chitosan/silk fibroin composite scaffolds for wound dressing

Three‐dimensional (3D) chitosan/silk fibroin (CS/SF) porous composite scaffolds have been prepared by simply coating a thin layer of CS onto spunlaced SF scaffolds via hydrogen‐bonding assembly technique, and they were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X‐ray diffraction (XRD), and mechanical property measurements. The results show that porous scaffolds have a pore diameter around 50–200 μm, and improved mechanical property compared with SF, resulting from strong intermolecular hydrogen bonding interactions between CS and SF, together with the maintained β‐sheet structure of SF. The medical and biological properties of the composite scaffolds were further evaluated. The results demonstrate that they possess good biocompatibility and a broad spectrum of antimicrobial properties. The in vivo animal experiments show that the composite scaffolds promote skin regeneration of rats without any teratogenic effect and inflection, thus they are very promising in the application of wound dressings. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42503.     

静电纺丝素蛋白组织工程支架的增强改性研究进展

常规静电纺丝法制得的丝素蛋白纤维毡的力学性能较差,不能很好地满足人体对生物组织工程支架的要求。为了提高丝素蛋白组织工程支架的力学性能,对丝素蛋白纤维毡进行增强改性是目前研究的热点。文章简要介绍了丝素蛋白的结构和性能及其在组织工程领域的应用研究,重点总结了提高静电纺丝素蛋白纤维毡力学性能的3种方法,即后处理、添加增强组分以及制备取向纳米纤维。