明胶固定化壳聚糖膜的细胞相容性评价

用碳二亚胺将明胶固定于壳聚糖膜表面,以改善壳聚糖的细胞相容性.采用MTT法评价膜材料对L929细胞的毒性.将壳聚糖膜(CS)、明胶固定化壳聚糖膜(CS-GEL)与人角膜上皮细胞(HCEC)体外复合培养,观察细胞的形态及生长情况,考察材料的细胞粘附率、材料对细胞活性与增殖的影响,并通过流式细胞术对细胞周期和凋亡进行分析.结果表明,CS-GEL具有良好的细胞粘附性,HCEC在CS-GEL上的生长和增殖情况优于CS,与CS相比,CS-GEL上HCEC的G1期比例下降,S期和G2期增加.明胶的引入缩短了细胞在膜表面的适应时间,使其尽快进入正常的细胞周期;同时表面固定的明胶可抑制细胞凋亡.因此,明胶固定化壳聚糖膜具有良好的体外细胞相容性,有望成为一种较好的角膜修复材料.     

静电纺壳聚糖/聚乙烯醇纳米纤维膜的制备及表征

通过静电纺丝技术首次将溶解在1%(体积分数)超低浓度乙酸溶液中的3%(wt,质量分数,下同)壳聚糖(CS)与溶解在去离子水中的11%聚乙烯醇(PVA)溶液进行混合,在20～22kV高压静电场下制备出直径在70～300nm之间、CS含量高达60%,具有均匀结构的CS/PVA纳米纤维膜。通过旋转流变仪、扫描电镜、X射线衍射仪、红外光谱、热重分析和万能试验机等手段对其混合溶液进行表征。结果表明:CS/PVA纳米纤维膜的形貌与CS和PVA的混合比例有关,当CS含量低于60%时,纤维形貌良好,当CS含量高于60%时,纤维中存在有液滴以及纺锤体。另外,CS与PVA之间存在强有力的氢键作用并具有很好的相容性,PVA可以降低壳聚糖的结晶性利于静电纺过程的进行;并且该CS/PVA纳米纤维膜具有较好的热稳定性和弹性,随着PVA比例的增加其最大拉伸强度可达到9.98MPa。     

聚乙烯醇/壳聚糖共混膜的制备及表征

用溶液共混法制备聚乙烯醇/壳聚糖(PVA/CS)共混膜,对共混膜进行了IR、DSC表征和吸水率、透光率、力学性能等进行测定.结果表明: PVA与CS分子链间在共混膜中有一定的相互作用,相容性好;CS的引入有利于改善PVA的吸水性、透光率和综合力学性能,但热稳定性有所降低.     

淀粉/壳聚糖/聚乙烯醇/明胶共混膜的制备及表征

制备了淀粉(CST)/壳聚糖(CS)/聚乙烯醇(PVA)/明胶(GEL)共混膜,测定了其透光性、透水汽性、吸水性及保水性;通过红外光谱(FT-IR)、X射线衍射(XRD)表征了聚乙烯醇-壳聚糖(PVA-CS)、聚乙烯醇-明胶(PVA-GEL)、聚乙烯醇-淀粉(PVA-CST)共混膜的特性。结果表明,PVA、CS、GEL与CST之间具有较强的相互作用。CS、GEL和CST的加入使PVA的结晶度降低。当CS/PVA/GEL/CST质量比为2/2/1/5%时,透光率最大,为86.7%;当CS/PVA/GEL/CST质量比为2/2/1/25%时,透水汽率最大,为1317.921g/m2;当CS/PVA/GEL/CST质量比为2/2/1/25%时,吸水率最大,为971.1%;当CS/PVA/GEL/CST质量比为3/1/1/5%时,保水率最大,为1168.9%。     

羧甲基壳聚糖和羧甲基甲壳素的生物学性质研究和比较

制备并纯化出了医用级羧化度为103．14％、脱乙酰度为97．18％的羧甲基壳聚糖和羧化度为96．37％的羧甲基甲壳素，对其对成纤维细胞生长作用和体内外可降解性、生物相容性进行了研究。结果表明，两种多糖均能不同程度地促进成纤维细胞的生长，其中以100μg／ml的羧甲基壳聚糖效果最好。体内外降解实验表明二者均具有良好的可降解性和生物相容性，其中羧甲基甲壳素降解的速度相对较快，而羧甲基壳聚糖的生物相容性更好，在体内降解7d后，已无明显炎症反应。     

电气石/壳聚糖复合纤维的表征及细胞相容性

以壳聚糖为基体,电气石为分散相,采用溶液纺丝法制备电气石/壳聚糖复合纤维,利用光学显微镜、扫描电镜以及红外光谱仪对材料进行表征。电气石/壳聚糖复合纤维与人骨肉瘤细胞株（MG63）体外共培养,初步评价了材料的细胞相容性。结果显示,电气石颗粒在复合纤维中分散均匀且被壳聚糖包裹,纤维表面无裸露电气石。细胞在电气石/壳聚糖复合纤维表面黏附及生长增殖状况良好,材料对细胞无明显毒性。该材料有望成为一种良好的创伤修复敷料。     

壳聚糖-聚磷酸钠聚离子复合物渗透汽化膜研究(Ⅱ)聚合条件和操作条件对膜分离性能的影响

选用聚阳离子电解质壳聚糖和聚阴离子电解质聚磷酸钠为膜材料，采用聚离子复合反应的方法制备出了一种新型的渗透汽化透水膜：壳聚糖—聚磷酸钠复合物膜(CS—SPP)，通过控制聚离子反应的条件如聚磷酸钠浓度，反应时间，从而改变聚离子反应程度，制备出了不同性能的聚离子膜．研究了壳聚糖-聚磷酸钠聚离子膜分离乙醇／水溶液的特性，探讨了聚离子反应条件、操作条件对膜分离性能的影响．     

掺杂无机纳米材料光催化双极膜的制备与表征

将柔性链聚乙烯醇(PVA)分别与刚性链天然高分子海藻酸钠(SA)和壳聚糖(CS)共混,以增强其柔韧性及双极膜界面层的相容性。然后分别以纳米无机半导体材料和戊二醛为交联剂,对PVA/SA和PVA/CS进行改性,制备了PVA-mSA/mCS双极膜。测定了双极膜的J-V曲线、膜阻抗、接触角和溶胀度。以扫描电镜对PVA-ZnO-SA/mCS膜成分与形貌作表征,膜厚约121μm,中间界面层厚约5μm。电子能谱图表明氧化锌均匀分布在阳膜层中。实验结果表明,采用纳米ZnO改性后双极膜的亲水性增强,具有更强的中间界面层水解离能力,较小的工作电压和较低的膜阻抗,可以广泛应用于绿色化学和环境治理。     

工艺条件对壳聚糖和聚乙烯醇共混膜的生物粘附性影响

壳聚糖和聚乙烯醇溶液经混合,采用相转化法成膜工艺制备壳聚糖和聚乙烯醇共混膜;以猪大肠膜为粘附对象,考察在不同工艺条件下制得共混膜对猪大肠膜的粘附特征。结果表明:当m(CS):m(PVA)=1:4时,共混膜的生物粘附强度最大;在甘油用量较少时,随着甘油的用量增加,粘附强度快速增强,在6%(wt,下同)时达到最大,当超过8%时,粘附强度明显下降后,随着甘油的用量增加,基本保持一个稳定的水平;在成膜温度为70℃时,所形成CS/PVA共混膜的粘附强度最大。扫描电镜照片显示所形成膜的微观形貌呈多孔结构,这种结构对其生物粘附性能会产生重要作用。     

PVA-壳聚糖/有机累托石复合膜的结构与性能

目的将聚乙烯醇(PVA)引入壳聚糖(CS)/有机累托石(OREC)复合体系制备插层效果、力学性能、抗紫外老化及阻隔性能良好的插层纳米复合膜。方法利用溶液流延法制备PVA-CS/OREC系列复合膜,以XRD及SEM研究复合膜的插层结构及OREC在基体中的分散性,研究复合膜的力学性能、抗紫外辐射性及水蒸气透过性。结果 OREC及PVA添加量较少时可与CS形成良好的插层结构。当OREC质量分数为2%,PVA质量分数为10%时的复合膜(标记为PVA10-CS/OREC2)插层结构最好,OREC在CS及PVA基体中分散性最好,与OREC质量分数为2%且不含PVA的复合膜(标记为CS/OREC2)相比,拉伸强度提高42.2%,断裂伸长率提高30%,水蒸气透过量降低10.2%,复合膜经紫外辐射后拉伸强度保持率、断裂伸长保持率仍达82.5%及68.2%。结论 PVA10-CS/OREC2膜可作为医用膜和药品、食品等的包装材料。     

Preparation and function of composite asymmetric chitosan/CM-chitosan membrane

A novel composite asymmetric chitosan/CM-chitosan membrane (C-P-C) was prepared, the top-layer was chitosan (CS), the intermediate was PVA, and the substrate was carboxymethyl chitosan (CM-CS). C-P-C membrane had capability in mechanical strength, light transparence, vapor permeability, and wound skin joining. The CS and CM-CS in C-P-C membrane were selected by series independent experiments, respectively. CS (MW 90,000 Da) had the highest antibacterial activity for E.coli. CM-CS had biocompatibility, no cytotoxicity, and had the activity of promoting growth of human skin fibroblast and inhibiting the growth of keloid fibroblast. The normal skin fibroblast can growth on the CM-CS surface of C-P-C, and have no conglomeration in higher cell density, and the keloid fibroblast could not growth on CM-CS surface of C-P-C. The animal experiment demonstrated that wound, covered with the C-P-C membrane, was hemostatic, healing quickly and had histocompatibility. The results indicated that the C-P-C membrane could be used as dressing of skin repair, and had the potential in promoting wound healing and inhibiting the keloid formation.     

聚乳酸复合纳米纤维创面敷料的制备及性能

采用静电纺丝技术制备了聚乳酸(PLLA)纳米纤维毡、壳聚糖/PLLA纳米纤维毡和明胶/PLLA纳米纤维毡。利用扫描电镜(SEM)、图像分析软件等手段研究了纳米纤维微观形貌,并研究各种创面敷料的吸水性、保水性和水蒸汽通透性等性能。结果表明,壳聚糖/PLLA、明胶/PLLA复合纳米纤维毡的吸水性和保水性有显著提高,水蒸汽通透性略有下降,是理想的创面敷料材料。     

An enhancement on healing effect of wound dressing: Acrylic acid grafted and gamma-polyglutamic acid/chitosan immobilized polypropylene non-woven

The wound dressing of acrylic acid-grafted and gamma-polyglutamic acid/chitosan-immobilized polypropylene non-woven fabric (PP-AAg-PGCi) was produced in this study. Gamma-polyglutamic acid (gamma-PGA) was first applied in this field to composed with chitosan. The PP-AAg-PGCi wound dressings were expected to enhance the water absorbing, water permeating and wound healing properties. The results showed that the immobilizing percentage, water absorbing value and water diffusion coefficient for PP-AAg-PGCi samples increased with the increase of the gamma-PGA in the immobilizing bath; whereas, decreased with the increase of the chitosan in the immobilizing bath. The immobilized chitosan was aggregating with the state of discontinuous and uneven mass materials on the surface of the immobilized gamma-PGA. The water absorbing, water permeating, and anti-bacterial properties of the PP-AAg-PGCi samples were much better than that of AA grafted and collagen/chitosan immobilized PP non-woven sample (PP-AAg-CCi) in our previous study. Anti-bacterial property for PP-AAg-PGCi samples was excellent. The effect on accelerating wound healing for PP-AAg-PGCi samples was strong. The product of the multi-layer material of PP-AAg-PGCi was expected to bestow better services for wound dressing.     

Development of asymmetric gradational-changed porous chitosan membrane for guided periodontal tissue regeneration

A novel kind of guided tissue regeneration (GTR) barrier membrane has been fabricated using an immersion–precipitation phase inversion technique (IPPI) with biodegradable natural polymer–chitosan. The membrane had an asymmetric gradational-changed porous structure including a dense skin layer, a transition region and a sponge-like porous layer. The concentration of chitosan solution and solvent evaporated time were two key factors that had significant effect on the porosity, average pore size, absorbed water ratio and mechanical properties of the porous membrane. The porous membrane not only degraded but maintaining the structure integrity for 5–6 weeks in the enzyme solution that can meet the demand for GTR. The biological experiment results showed the asymmetric membranes did not cause anaphylactic reaction, hemolysis, cytotoxicity and pyrogenic effect. All of the results indicated that the porous chitosan membrane had excellent biocompatibility and biodegradation, which could be used as a barrier for preventing apical migration of gingival epithelial cells and promoting growth of periodontal ligament cells in periodontal therapy.     

Fabrication of electrospun polycaprolactone coated withchitosan-silver nanoparticles membranes for wound dressing applications

In this study, electrospun polycaprolactone membrane coated with chitosan-silver nanoparticles (CsAg), electrospun polycaprolactone/chitosan/Ag nanoparticles, was fabricated by immersing the plasma-treated electrospun polycaprolactone membrane in the CsAg gel. The plasma modification of electrospun polycaprolactone membrane prior to CsAg coating was tested by methylene blue stain and scanning electron microscope. The presence of silver and chitosan on the plasma-treated electrospun polycaprolactone membrane was confirmed by energy-dispersive X-ray spectroscopy and FT-IR spectrum. Scanning electron microscope observation was employed to observe the morphology of the membranes. The release of Ag ions from electrospun polycaprolactone/chitosan/Ag nanoparticles membrane was tested using atomic absorption spectrometry. Electrospun polycaprolactone/chitosan/Ag nanoparticles membrane inherited advantages from both CsAg gel and electrospun polycaprolactone membrane such as: increasing biocompatibility, mechanical strength, and antibacterial activity against both Gram-negative and Gram-positive bacteria. Thus, this investigation introduces a highly potential membrane that can increase the efficacy of the wound dressing process.     

Chitosan and alginate polyelectrolyte complex membranes and their properties for wound dressing application

This study investigated the characteristics and drug release properties of membranes of chitosan and alginate prepared via a casting/solvent evaporation technique. Membranes of chitosan and alginate with silver sulfadiazine as model drug incorporated in different concentrations and different membrane compositions were obtained. The polyblend solution viscosity reached to the highest at the composition polyblends of (1:1). This chitosan/alginate membranes showed pH- and ionic strength-dependent water uptake properties and had the WVTR rang from 442 to 618 g/m²/day. The maximum value of the dry membrane of breaking strength was 52.16 MPa and the maximum value of the wet membrane breaking elongation was 46.28%. The results of controlled release studies showed that the silver sulfadiazine release rate was the fastest when the alginate content was 50%. On the basis of the requisite physical properties, the chitosan–alginate PEC membrane can be considered for potential wound dressing or controlled release application.     

壳聚糖/AKD乳液改善纸浆模塑制品防水防油性能的研究

目的 以壳聚糖/AKD乳液替代传统的AKD乳液,作为安全无毒的防水防油剂,以改善纸浆模塑的防水防油性能。方法 采用壳聚糖作为乳化剂,在高剪切分散乳化条件下与AKD蜡共混,获得稳定均一的壳聚糖/AKD乳液,然后通过浆内施胶的方式制备纸浆模塑制品,对纤维的滤水性能、纸浆模塑制品的力学性能以及防水防油性能进行研究。结果 以壳聚糖质量分数为1.5%的壳聚糖醋酸溶液,可制备得到AKD蜡质量分数为5%的乳白色壳聚糖/AKD乳液;乳液的添加未影响纤维的滤水性能,且当其用量占绝干浆质量的7%时,纤维悬浮液的打浆度和保水值分别达到23 °SR和(1.71±0.06)g/g,满足生产要求。对比未添加乳液的样品,添加了质量分数为7%的乳液后,纸浆模塑制品的力学性能,包括紧度、抗张强度、耐破指数和撕裂强度分别提高了26.2%、60.6%、152.6%和67.1%,Cobb60值降低到了(18.5±0.68)g/m²,静态水接触角提高到了(119±4.1)°,体现防油性能的Kit值提高到了第8等级,油接触角提高到了(97.9±3.1)°。纸浆模塑制品具有良好的防热水和防热油的性能。结论 壳聚糖/AKD乳液可作为一种新型防水防油助剂用于纸浆模塑制品生产,拓展了环保造纸助剂品类。     

Comparative lyophilized platelet-rich plasma wafer and powder for wound-healing enhancement: formulation,in vitro and in vivo studies

Platelet-rich plasma (PRP) accelerates wound healing, as it is an excellent source of growth factors. PRP was separated from whole human blood by centrifugation. PRP powder and wafers were prepared by lyophilization, with the wafers prepared using sodium carboxymethylcellulose (Na CMC). The PRP wafers showed porous structures, as indicated by scanning electron microscopy (SEM) images, and the ability of the wafer to absorb exudates and thus promote wound healing was tested with the hydration capacity test. The platelet count was tested and indicated that the presence of PRP in the wafers had no effect on the platelet count. An antimicrobial activity test was carried out, showing that PRP had antibacterial activity against Gram-negative bacteria. Compared with lyophilized PRP powder and PRP-free wafers, PRP wafers showed the highest percent of wound size reduction on induced wounds in rats. Histopathological examination of rat skin showed that the PRP wafers achieved the shortest healing time, followed by the lyophilized PRP powder and finally the PRP-free wafers. The present study revealed that PRP can be formulated as a wafer, which is a promising pharmaceutical delivery system that can be used for enhanced wound-healing activity and improved the ease of application compared to lyophilized PRP powder.     

In vitro evaluation of biocompatibility of different wound dressing materials

The in vitro biocompatibility of newly developed wound dressings consisting of different chitosan salts (chitosan lactate, glutamate and chloride) and a chitosan derivative (methylpyroolidinone chitosan) was compared with three commercially available wound dressings made of collagen, calciumalginate, and gelatin, by evaluation in a fibroblast cell culture system. Three experimental models which reflect relevant stages of wound healing were used, and the significant influence of the experimental setting on the results was demonstrated. Collagen and methylpyrrolidinone chitosan were the most compatible materials under the investigated test conditions. Chitosan chloride and glutamate were the least compatible substances. The results indicated that wound dressings made of chitosan lactate and methylpyrrolidinone chitosan as well as the three commercially available dressings are well tolerated.     

Copper(II)-EDTA sorption onto chitosan and its regeneration applying electrolysis

Cu(II)-EDTA (ethylendiaminetetraacetate) complexes are widely used in the manufacture of printed circuit boards. In order to avoid the outlet into the environment the sorption of complexes onto chitosan is proposed. The uptake of both Cu(II) and EDTA proceeds in weakly acidic (pH 3-5) and strongly alkaline (pH > 12) solutions. In acidic solutions EDTA sorption prevails. FT-IR investigations have shown that in acidic solutions the amide bonds between -COOH groups of EDTA and -NH2 groups of chitosan were formed. In alkaline solutions the single EDTA sorption does not proceed. In this media the sorption is enhanced by Cu(II) ions. The possible sorption mechanisms are discussed. The uptake of both Cu(II) and EDTA by chitosan depends on the ratio between them in solutions. EDTA sorption in acidic solutions increases with increase in its concentration while that of Cu(II) decreases. In alkaline solutions the sorption of both Cu(II) and EDTA increases with increase in Cu(II) concentration. The use of electrolysis enables to regenerate chitosan and to reuse it. During electrolysis copper is deposited onto the cathode and EDTA is oxidized onto the anode. The current efficiency depends on the current intensity, the load of chitosan and the pH of the background electrolyte. Electrolysis under the most favorable conditions ensures the 10-cycles regeneration without considerable changes in the sorption properties of chitosan. FT-IR spectra of the initial and regenerated chitosans are similar.