静电纺丝法制备载银敷料及其性能表征

采用静电纺丝方法制备了聚乳酸(PLA)/聚己内酯(PCL)-聚乙烯醇(PVA)-壳聚糖(CS)-银(Ag)抗菌剂纳米纤维敷料。通过扫描电镜观察了纤维的微观结构,同时对其亲水性能及抗菌性进行了测试,结果表明,通过使用甲酸/丙酮作为CS的溶剂,同时添加PVA改善CS和PLA/PCL的相容性,能够获得直径均匀的纳米纤维,其静态接触角大幅度降低,吸水性、保水性和水汽透过率有显著的提高。当银抗菌剂的质量分数在0.125‰时,敷料对于革兰氏阳性菌金黄色葡萄球菌和革兰氏阴性菌大肠杆菌具有良好的抗菌活性,可用于制备创面抗菌敷料。     

取向TSF/PLLA静电纺纳米纤维毡的制备及其生物相容性

利用静电纺丝技术制备了取向的柞蚕丝素/左旋聚乳酸(TSF/PLLA)纳米纤维毡。通过扫描电子显微镜(SEM)、X射线衍射分析(XRD)和拉伸测试分别对TSF/PLLA纳米纤维的形貌、结晶结构及力学性能进行了研究。将人成骨肉瘤细胞(MG-63)种植在TSF/PLLA纳米纤维上,通过荧光显微镜分析和MTT(四甲基偶氮噻唑蓝比色法),观察细胞在材料表面的生长情况,评价纳米纤维的生物学性能。结果表明,TSF含量为10%时,纤维直径分布均匀,结晶度高。但是,TSF含量超过10%后,纤维直径粗细不匀明显,纤维的力学性能下降。与无规纤维毡相比,取向的纳米纤维毡力学性能优异,初始模量高,更能够促进细胞增殖,对细胞的生长行为影响大。     

氧化石墨烯增强的骨仿生静电纺左旋聚乳酸纳米纤维支架的制备及表征

利用静电纺丝技术制备了左旋聚乳酸/氧化石墨烯(PLLA/GO)复合纳米纤维毡。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、孔隙率测试、傅里叶红外光谱分析(FTIR)以及拉伸测试分别对PLLA/GO纳米纤维的形貌结构、孔隙率及力学性能进行了研究。将小鼠骨髓间充质干细胞(MSCs)种植在TSF/PLLA纳米纤维上,通过荧光显微镜分析和碱性磷酸酶(ALP)测试、SEM观察细胞在材料表面的生长以及矿物沉积情况评价复合纳米纤维的生物学性能。结果表明,与纯的PLLA静电纺纳米纤维支架相比,PLLA/GO复合纳米纤维支架的纤维直径显著减小,孔隙率增大,力学性能明显得到改善,拉伸强度和杨氏模量均高于纯PLLA纳米纤维支架将近3倍,而且能够更好地促进MSCs的粘附、增殖和分化。     

含纳米银的明胶/壳聚糖纳米纤维的制备及其抗菌性能研究

以浓度为88%的甲酸溶液作为纺丝溶剂,采用静电纺丝和紫外光照射还原的方法制备了含纳米银颗粒的明胶/壳聚糖纳米纤维。研究发现,壳聚糖的加入量低于明胶质量的3/16时可以得到纳米纤维,纤维平均直径随着硝酸银加入量的增大而减小,纤维表面纳米银的平均直径随着硝酸银加入量的增大而增大,在纺丝体系中硝酸银的加入量存在一个极限值。所制得含纳米银的明胶/壳聚糖纳米纤维对金黄色葡萄球菌和绿脓杆菌具有较好的抑菌性能,纺丝时加入1%硝酸银制得纳米纤维膜的抑菌率达到99%以上,这种抗菌型纳米纤维可以应用于医用敷料等领域。     

明胶接枝共聚制备高吸水性树脂的研究

采用明胶与丙烯酸(钾)接枝共聚制备高吸水性树脂,并考察了引发剂、交联剂、明胶的用量及丙烯酸中和度、单体质量分数等各因素对产物吸(盐)水倍率的影响;所得的高吸水性树脂的吸水倍率为535.3g/g,吸盐水倍率为53.8g/g,其吸(盐)水倍率较好,且在较低温度下的保水性也较好.     

明胶-壳聚糖/纳米SiO_2原位载药复合膜的制备及性能研究

利用明胶、壳聚糖和纳米SiO_2,制备了明胶-壳聚糖/纳米SiO_2复合膜,对复合膜的溶胀性、机械强度等进行测试。然后将明胶-壳聚糖/纳米SiO_2复合膜用于阿司匹林的原位负载,研究纳米SiO_2用量和模型药物阿司匹林用量对原位载药复合膜缓释性能的影响。结果表明,纳米SiO_2的引入能够降低复合膜在水中的溶胀性,提高复合膜的机械强度;随着纳米SiO_2用量的增加,复合膜原位负载阿司匹林的缓释效果增加;阿司匹林用量为0.5%时,明胶-壳聚糖/纳米SiO_2原位载药复合膜具有较好的缓释效果。     

影响壳聚糖-胶原蛋白冻干海绵敷料结构、性能的因素

壳聚糖-胶原复合敷料具有良好的生物相容性、抗菌性和促进表皮细胞生长等特性,可作为深二度烧伤敷料。通过冷冻干燥法制得的海绵敷料的外观、内部结构、吸水率、舒适性等性能取决于制备条件,其中预冻步骤最为关键。本工作探讨了-70℃、-40℃、-20℃的三种预冻条件对冻干产品外观和内部结构的影响,同时考察不同物料浓度(2.0~3.5%)和不同壳聚糖/胶原蛋白比例(2/1、1/1、1/2)时海绵敷料性能,实验表明,-40℃预冻30min,物料浓度2.5%,壳聚糖/胶原蛋白比例2/1,所制得的海绵敷料外观工整,内部孔结构均匀,且具有良好的结构稳定性、吸水性和舒适性。红外光谱分析表明,壳聚糖-胶原蛋白冻干海绵由于氢键交联作用,使冻干产品不同于原材料壳聚糖或胶原蛋白,冻干产品具有更牢固的组织结构。     

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%。     

聚乙烯醇/壳聚糖/明胶水凝胶的合成及其对苯酚的吸附研究

以聚乙烯醇(PVA)、壳聚糖和明胶为原料、戊二醛为交联剂,在酸性溶液中通过共混交联反应合成了聚乙烯醇/壳聚糖/明胶水凝胶,单因素法讨论了影响水凝胶性能的因素如:反应物质量比、交联剂用量、反应温度、反应时间等聚乙烯醇/壳聚糖/明胶水凝胶,对不同浓度苯酚溶液的吸附研究.研究结果表明聚乙烯醇/壳聚糖/明胶水凝胶对苯酚有较好的吸附性能.     

明胶-壳聚糖-纳米SiO2复合微胶囊的制备及结构

以石蜡和壳聚糖作为囊芯材料,以明胶作为壁材,制备明胶-壳聚糖-纳米SiO_2复合微胶囊。通过油水比、壳聚糖和明胶中分别引入纳米SiO_2等因素的调节,研究了其对微胶囊性能、结构的影响。采用光学显微镜、扫描电子显微镜(SEM)对微胶囊形貌等微观结构进行表征。结果表明,油水比为3∶1时,制备的微胶囊结构和性能较好,在此基础上分别以不同的方式在壳聚糖和明胶中引入不同粒径的纳米SiO_2。结果表明,未引入纳米SiO_2制备的微胶囊呈球形结构,部分为多核微胶囊;当在壳聚糖或明胶中加入SiO_2时,微胶囊壁材出现多孔结构,球形度降低,随着SiO_2量的增加,微胶囊壳层孔状结构增多,微胶囊的热损失率也随之增大;不同粒径的纳米SiO_2无论引入壳聚糖还是明胶中,微胶囊的热损失率都是随着SiO_2含量的增加而增大;较大粒径的纳米SiO_2引入后微胶囊热损失率小于小粒径纳米SiO_2引入后微胶囊的热损失率。     

Electrospun polyvinylidene pyrolidone/gelatin membrane impregnated with silver sulfadiazine as wound dressing for burn treatment

Nanofibrous membranes used for burn treatment have become widely popular due to their large surface area and high porous structure. In this study, electrospinning was used to fabricate a blended nanofibrous membrane of polyvinylidene pyrolidone (PVP) and gelatin, to use as wound dressing. The physical and mechanical properties of this novel membrane were investigated using SEM, FTIR and tensile tests. Results showed that poor mechanical properties of gelatin, which are preferred in medical applications for curing burns as they allow for antigen activity and skin repair, can be enhanced by adding PVP in the solution. Silver sulfadiazine (AgSD), an antibacterial agent, was also impregnated into the PVP/gelatin nanofibrous structure during electrospinning. The membrane thus fabricated showed antibacterial activities against both the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. AgSD release behaviour of fabricated samples indicated short-term drug delivery. It was concluded that the proposed drug-loaded membrane can be used as wound dressing, specifically, in treating skin burns.     

Electrospinning of gelatin and gelatin/poly(l-lactide) blend and its characteristics for wound dressing

Gelatin nanofibres were electrospun from its aqueous acetic acid solution. Electrospinning parameters, such as concentration of aqueous acetic acid and gelatin solutions, electric field and spinning distance, were examined to investigate the electrospinnability of gelatin solutions and the morphology of gelatin nanofibrous mats. Nanofibrous mats from poly(l-lactide) (PLLA) and gelatin/PLLA solutions were obtained. The electrospun mats showed controlled evaporative water loss, promoted fluid drainage ability, and excellent biocompatibility, and therefore have a potential application as wound dressing.     

Effect of graphene oxide nanosheets on the physico-mechanical properties of chitosan/bacterial cellulose nanofibrous composites

In this work, novel chitosan/bacterial cellulose (CS/BC) nanofibrous composites reinforced with graphene oxide (GO) nanosheets are introduced. As cell attachment and permeability of nanofibrous membranes highly depend on their fiber diameter, the working window for successful electrospinning to attain sound nanofibrous composites with a minimum fiber diameter was determined by using the response surface methodology. It is shown that the addition of GO nanosheets to CS/BC significantly reduces the average size of the polymeric fibers. Their mechanical properties are also influenced and can be tailored by the concentration of GO. Fourier transform infrared spectroscopy reveals hydrogen bonding between the GO nanosheets and the polymer matrix. A decrease in the hydrophilicity of the electrospun nanofibers and their water vapor permeability with the addition of GO are also reported. The prepared nanofibrous composites are potentially suitable candidates for biomedical applications such as skin tissue engineering and wound dressing.     

Fabrication and characterization of PCL/gelatin/chitosan ternary nanofibrous composite scaffold for tissue engineering applications

In the present study, we have fabricated a ternary composite nanofibrous scaffold from PCL/gelatin/chitosan, by electrospinning technique, using a solvent system—chloroform/methanol for polycaprolactone (PCL) and acetic acid for gelatin and chitosan, for tissue engineering applications. Field emission scanning electron microscopy (FE-SEM) was used to investigate the fiber morphology of the scaffold and it was found that the fiber morphology was influenced by the concentrations of PCL, gelatin, and chitosan in polymer solution during electrospinning. X-ray diffraction, Fourier transform infrared, and thermogravimetric (TG) analysis results showed some interactions among the molecules of PCL, gelatin, and chitosan within the scaffold. In-vitro cell culture studies were done by seeding L929 mouse fibroblasts on fabricated composite scaffold, which confirmed the cell viability, high cell proliferation rate, and cell adhesion on composite scaffold as indicated by MTT assay, DNA quantification, and FE-SEM analysis of cell-scaffold construct. Thus, the ternary composite scaffold made from the combination of PCL (synthetic polymer), gelatin, and chitosan (natural polymer) may find potential application in tissue engineering.     

Electrospun poly(l-lactide)/zein nanofiber mats loaded with <Emphasis Type="Italic">Rana chensinensis</Emphasis> skin peptides for wound dressing

Electrospun nanofiber mats can display impressive performance as an ideal wound dressing. In this study, poly(l-lactide)(PLLA)/zein nanofiber mats loaded with Rana chensinensis skin peptides (RCSPs) were successfully produced by two different electrospinning techniques, blend and coaxial, with the goal of developing a wound dressing material. The nanofiber mats were investigated by environmental scanning electron microscope (ESEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), water contact angle, mechanical tests and cell viability. The resulting nanofiber mats exhibited smooth surfaces, tiny diameters and different cross-sectional shapes from pure PLLA and zein nanofibers. The FTIR result showed that PLLA, zein and RCSPs were well dispersed, without chemical interactions. Compared with coaxial nanofiber mats, blending zein-RCSPs with PLLA enhanced hydrophilicity but decreased mechanical properties. Adding RCSPs into the electrospun nanofibers significantly improved the mechanical properties of the mats. Cell viability studies with human foreskin fibroblasts demonstrated that cell growth on PLLA/zein-RCSPs nanofiber mats was significantly higher than that on PLLA/zein nanofiber mats. The results indicate that nanofiber mats containing RCSPs are potential candidates for wound dressing.     

Electrospun polyimide/titanium dioxide composite nanofibrous membrane by electrospinning and electrospraying

Fibrous membrane with a fibre diameter of 229 +/- 35 nm was fabricated from polyimide solution by electrospinning. Nanofibrous membrane with a fibre diameter of 251 +/- 37 nm was fabricated by combined electrospinning and electrospraying for polyimide/TiO2. Among the different solvents studied, ethanol was the effective solvent for dispersing the TiO2 nanoparticles in the nanofibrous matrix during electrospraying. The average pore size of polyimide membrane was obtained in the range 0.79-0.89 microm whereas the average pore size of polyimide/TiO2 membrane was found to be in the range 1.23 microm. The tensile stress of polyimide nanofibrous membrane and also polyimide/TiO2 composite fibrous membrane determined to be 0.36 MPa and 0.65 MPa respectively. Nanofibrous membrane containing TiO2 nanoparticles on the surface of the polyimide nanofibres improved the mechanical stability of the membrane.     

Fabrication,characterization and in vitro drug release behavior of electrospun PLGA/chitosan nanofibrous scaffold

In this study both aligned and randomly oriented poly(d,l-lactide-co-glycolide) (PLGA)/chitosan nanofibrous scaffold have been prepared by electrospinning. The ratio of PLGA to chitosan was adjusted to get smooth nanofiber surface. Morphological characterization using scanning electron microscopy showed that the aligned nanofiber diameter distribution obtained by electrospinning of polymer blend increased with the increase of chitosan content which was similar to that of randomly oriented nanofibers. The release characteristic of model drug fenbufen (FBF) from the FBF-loaded aligned and randomly oriented PLGA and PLGA/chitosan nanofibrous scaffolds was investigated. The drug release rate increased with the increase of chitosan content because the addition of chitosan enhanced the hydrophilicity of the PLGA/chitosan composite scaffold. Moreover, for the aligned PLGA/chitosan nanofibrous scaffold the release rate was lower than that of randomly oriented PLGA/chitosan nanofibrous scaffold, which indicated that the nanofiber arrangement would influence the release behavior. In addition, crosslinking in glutaraldehyde vapor would decrease the burst release of FBF from FBF-loaded PLGA/chitosan nanofibrous scaffold with a PLGA/chitosan ratio less than 9/1, which would be beneficial for drug release.     

Composite poly-l-lactic acid/poly-(α,β)-dl-aspartic acid/collagen nanofibrous scaffolds for dermal tissue regeneration

Tissue engineering scaffolds for skin tissue regeneration is an ever expounding area of research, as the products that meet the necessary requirements are far and elite. The nanofibrous poly-l-lactic acid/poly-(α,β)-dl-aspartic acid/Collagen (PLLA/PAA/Col I&III) scaffolds were fabricated by electrospinning and characterized by SEM, contact angle and FTIR analysis for skin tissue regeneration. The cell-scaffold interactions were analyzed by cell proliferation and their morphology observed in SEM. The results showed that the cell proliferation was significantly increased (p ≤ 0.05) in PLLA/PAA/Col I&III scaffolds compared to PLLA and PLLA/PAA nanofibrous scaffolds. The abundance and accessibility of adipose derived stem cells (ADSCs) may prove to be novel cell therapeutics for dermal tissue regeneration. The differentiation of ADSCs was confirmed using collagen expression and their morphology by CMFDA dye extrusion technique. The current study focuses on the application of PLLA/PAA/Col I&III nanofibrous scaffolds for skin tissue engineering and their potential use as substrate for the culture and differentiation of ADSCs. The objective for inclusion of a novel cell binding moiety like PAA was to replace damaged extracellular matrix and to guide new cells directly into the wound bed with enhanced proliferation and overall organization. This combinatorial epitome of PLLA/PAA/Col I&III nanofibrous scaffold with stem cell therapy to induce the necessary paracrine signalling effect would favour faster regeneration of the damaged skin tissues.     

用于黑素细胞培养和移植的壳聚糖/明胶复合交联膜的制备与表征

利用生物相容膜材料培养黑素细胞可用于白癜风移植治疗并提高移植成功率。本文通过物理交联方法制备了厚度约50微米的壳聚糖/明胶复合交联膜(CCGM),对CCGM的物理、机械性能及其用于黑素细胞的培养进行了研究。研究表明CCGM具有较高的吸水率和良好的水蒸气透过率,符合伤口敷料的要求。动态机械性能和拉伸实验结果显示该交联复合膜有良好的湿强度,能满足细胞培养、转移和移植的使用要求。此外,CCGM支持黑素细胞的生长和增殖,有望用于白癜风的移植治疗。     

Effect of chitosan-polyvinyl alcohol blend nanofibrous web on the healing of excision and incision full thickness wounds

Chitosan-polyvinyl alcohol (PVA) blend nanofibrous webs were fabricated in different blend ratios through electrospinning procedures. From scanning electron microscopy (SEM) results, 25/75 blend ratio of chitosan-PVA was selected for biological studies. In vivo studies were carried out on the dorsum of rats of two types: longitudinal incisional wounds (n=8 rats) and round excisional wounds (n=8). Pathological study was done on the wounds to investigate the healing process. The histological study in wound healing indicated that the administration of chitosan nanofibrous web improved the wound healing, qualitatively and quantitatively.