生物降解性防术后粘连膜的实验研究

本文首次采用新型医用天然高分子材料壳聚糖作膜材料，制备了可降解吸收防术后粘连膜，并通过动物实验研究其生物降解性和生物相容性．初步研究结果表明，壳聚糖具有很好的成膜性。壳聚糖膜在小鼠体内可以缓慢降解，并具有较好的生物相容性，是一种很有发展前景的天然防术后粘连膜材料。     

壳聚糖-羧甲基壳聚糖复合膜的研制及其生物相容性评价

壳聚糖膜降解较慢^[1]，为了加快其降解速度，研制了壳聚糖-羧甲基壳聚糖复合膜(以下简称复合膜)并进行了生物学评价。结果表明，该复合膜具有很好的生物相容性，可以满足体内植入膜的基本要求。     

生物降解性防术后粘加膜的实验研究

本文首先采用新型医用天然高分子材料壳聚糖作膜材料，制备了可降解吸收的防术后粘连膜，并通过动物实验研究其生物降解性和生物相容性。初步研究结果表明，壳聚糖具有很好的成膜性。壳莫大 半导体环境可以缓慢降解，并具有较好的生物相容性，是一种很有发展前景的天然防术后宫膜材料。     

壳聚糖大鼠颅内组织相容性的初步观察

本实验探讨了生物可降解的天然高分子缓释材料壳聚糖在脑组织中的生物相容性.以期为临床提供可用于颅内植入化疗的药物缓释高分子载体.我们以32只SD大鼠为研究对象,随机分为实验组和对照组,分别植入壳聚糖和明胶海绵.观察术后的行为改变和3,7,14,30天时的局部组织反应(HE染色).观察发现所有动物无明显行为改变,术后3,7,14,30天的组织学观察表明壳聚糖与明胶海绵有类似的异物反应.因此壳聚糖具有良好的脑组织生物相容性,并可安全的降解.可作为颅内植入缓释化疗药物的载体.     

角膜修复用改性明胶交联膜的生物相容性评价

本文对自制的改性壳聚糖-明胶交联膜(MC-Gel)与壳聚糖-明胶交联膜(CS-Gel)的理化性能、生物相容性进行测定与评价,探讨其用于角膜组织修复与重建的可行性。采用紫外分光光度计测定了交联膜的透光率及渗透性,结果显示两组交联膜的透光率超过90%,且对葡萄糖、色氨酸与NaCl的渗透率均接近或优于人角膜的渗透率,可满足角膜修复对透光率及营养物质透过的要求。同时,采用MTT法测定了人角膜上皮细胞(HCEC)在两组膜上的生长活性,并评价了两组交联膜在兔眼角膜内的组织相容性。实验结果表明,MC-Gel能较好地支持HCEC在其上增殖,且植入兔眼角膜后无明显炎症反应,术后4个月材料全部降解。因此,该交联膜具有良好的理化性能与眼组织相容性,有望成为一种良好的角膜修复材料。     

植入式葡萄糖传感器膜材料壳聚糖与Nafion的组织相容性比较

背景：壳聚糖是天然高分子多糖,可单独或者与其他材料复合制作敷料、药物、基因载体、生物涂层、组织工程支架、传感器膜材料等。 目的：了解壳聚糖作为植入式葡萄糖传感器膜材料的组织相容性,并与Nafion膜进行对比。 方法：制备壳聚糖膜并对其理化性质进行表征,比较壳聚糖膜皮下植入与肌肉植入、Nafion膜肌肉植入的生物相容性。 结果与结论：壳聚糖膜的厚度、溶胀率、表观密度等理化参数可以通过浓度、铸膜液体积来控制;壳聚糖膜能生物降解,63 d皮下植入的降解率为(17.0±9.9)%,说明壳聚糖的体内降解速度较慢。壳聚糖膜皮下植入引起的炎症反应较肌肉植入重,63 d后形成的纤维包膜比肌肉植入要厚(P < 0.05);肌肉植入Nafion与壳聚糖膜引起材料周围纤维包膜厚度差异无显著性意义(P > 0.05),两者均在15 d以后趋于稳定。证明壳聚糖膜能生物降解,与Nafion膜均有较好的组织相容性。     

温敏性壳聚糖止血膜的止血作用及体内降解吸收

背景：尽管温敏性壳聚糖是壳聚糖的一种,但其止血效果、组织相容性及体内代谢吸收情况还需要验证。目的：探讨温敏性壳聚糖止血膜的止血作用、体内降解和组织相容性。方法：取SD大鼠48只,随机均分为4组,同时进行两种实验：①制作肝脏创面出血模型,其中3组分别采用温敏性壳聚糖止血膜、纤维素止血棉和明胶海绵止血材料贴敷大鼠肝创面止血,以不做任何处理的为空白对照。记录出血时间及出血量。②在上述3组大鼠的股四头肌内分别再植入对应的止血材料,空白对照组不植入任何材料。术后1,2,3,4,6周取两处创面行大体观察,术后4周行苏木精-伊红染色和电镜观察。结果与结论：温敏性壳聚糖组、纤维素组止血时间和出血量少于空白对照组、明胶海绵组(P < 0.05)。温敏性壳聚糖止血膜于术后6周完全降解,纤维素止血棉于术后3周完全降解,明胶海绵于术后2周完全降解。温敏性壳聚糖组肝小叶结构完整,肝细胞结构基本正常,肿胀轻,炎症细胞浸润程度轻,电镜显示整个肝细胞外形结构清楚,细胞核无破损,细胞器良好;肌肉纤维结构完整,炎症细胞浸润程度轻,电镜显示肌纤维走向整齐,肌细胞核形态正常,细胞器良好。可见温敏性壳聚糖止血膜具有较好的止血作用和组织相容性。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

壳聚糖相对分子量对壳聚糖膜与角膜基质细胞相容性的影响

以脱乙酰度为95％，相对分子量分别为130KDa、220KDa、300KDa和500KDa的壳聚糖制备不同的壳聚糖膜。以各种壳聚糖膜作为基质，体外培养兔角膜基质细胞，通过观察角膜基质细胞在不同壳聚糖膜上的生长状态、贴附情况、生长曲线以及乳酸脱氢酶的活性，研究壳聚糖相对分子量对壳聚糖膜与角膜基质细胞生物相容性的影响。实验结果表明壳聚糖相对分子量对壳聚糖膜与角膜基质细胞的相容性具有重要的影响，相对分子量过高或过低的情况下，壳聚糖膜与角膜基质细胞相容性较差，对细胞损伤程度较大，细胞在膜上的贴附、生长能力较差；以相对分子量在200KDa～300KDa之间的壳聚糖制备出的膜与角膜细胞具有较好的相容性，细胞可在膜上长成密集单层，适合作为角膜培养的支架材料。     

N-乙酰化壳聚糖膜的制备和性质研究

以乙酸和甲醇为介质，利用壳聚糖和乙酸酐制备出N-乙酰化壳聚糖膜。对膜的亲水性、吸水性、结晶性、透光性、渗透性以及对血清蛋白的吸附性和与兔角膜上皮细胞的生物相容性进行了研究。结果表明N-乙酰化壳聚糖膜有一定的亲水性、吸水性、结晶性，有很好的透光性和渗透性，对血清蛋白有一定的吸附能力，以该膜为载体培养兔角膜上皮细胞实验结果表明膜与兔角膜上皮细胞具有很好的生物相容性。     

壳聚糖管状支架的制备及生物降解性

背景:作者课题组在进行肺组织瓣修补食管缺损实验中,发现硅胶支架和金属支架都不理想,都存在排斥反应和远期并发症,为寻找一种理想的生物型可自行降解支架,将壳聚糖制成管型支架,观察其在生物体内的相容性和降解性,为食管重建提供一种可降解支架。目的:探讨壳聚糖管状支架的制备方法及其生物特性。方法:利用乙酸溶液制备60g/L的壳聚糖乙酸水溶胶,采用成膜方法制管后用NaOH脱下壳聚糖导管,取内径5mm管,切成段,长度2mm,消毒,并将壳聚糖管植入大鼠组织内,分别于不同时间段大体及光镜下观察其生物相容性及体内降解性。结果与结论:壳聚糖导管光滑,韧性好,吸收水分变软,组织生物相容性好,随时间可被组织吸收降解。该方法提供了制备壳聚糖导管的一种新方法,并证实了其组织相容性和生物可降解性。     

Liver tissue responses to gelatin and gelatin/chitosan gels

Gelatin and gelatin/chitosan gels, crosslinked using glutaraldehyde, were previously developed as substrates for three-dimensional cell-assembly techniques. In this study, the biocompatibility and biodegradation of gelatin and gelatin/chitosan gels were evaluated following implantation in rat livers for periods up to 16 weeks. The two gels were characterized by different inflammatory responses and degradation rates. The gelatin/chitosan gel is more efficient in inducing fibrin formation and vascularization at the implant-host interface. The degrees of inflammatory reaction for the gelatin/chitosan gel were significantly stronger than the gelatin gel. Advanced biodegradation of the gelatin gels was observed. These data indicate that the gelatin gel has better liver tissue biocompatibility and a faster biodegraded rate than the gelatin/chitosan gel.     

Mechanical and biocompatible influences of chitosan fiber and gelatin on calcium phosphate cement

Calcium phosphate cement (CPC) is a widely used bone substitute in the clinic; however, the low strength of CPC limits its utilization. In this study, we investigated mechanical influences of chitosan fiber combined with gelatin on CPC, and examined the biocompatibility of the new composite with rat bone marrow stromal cells. Compared to the fiber impregnated in phosphate buffered saline (80.5 MPa), our study showed that tensile strength of chitosan fiber increased 106 and 114% with the impregnation of gelatin at the mass fraction 5 and 10%, although this increase was not statistically significant. It was demonstrated by Fourier transform infrared spectroscopy that the characteristic absorption bands of chitosan were changed with the addition of gelatin. The optimal flexural strength enhancement was obtained when CPC was reinforced with fiber at volume fraction of 30% and gelatin at mass fraction of 5% (maximum: 12.31 MPa). The fiber morphology was more compact when the chitosan fibers impregnated with gelatin at mass fraction of 5 or 10% than chitosan alone. The fracture analysis showed that the new CPC-chitosan fiber-gelatin composite presented many remnants of CPC adhered to fibers. Short minimum essential medium extract test showed no cell growth inhibition after the addition of the new composite. Rat bone marrow stromal cells retain the ability to spread and grow on the composite. Our studies demonstrated that the flexural strength is greatly increased by using CPC incorporated with proper ratio of CF and gelatin. More over, the new composite demonstrated biocompatibility in vitro.     

Study on physical properties and nerve cell affinity of composite films from chitosan and gelatin solutions

A series of chitosan-gelatin composite films was prepared by varying the ratio of constituents. FT-IR and X-ray analysis showed good compatibility between these two biopolymers. Differential scanning calorimetry (DSC) analysis indicated that the water take-up of chitosan film increased when blended with gelatin. Composite film exhibited a lower Young's modulus and a higher percentage of elongation-at-break compared with chitosan film, especially in wet state. All composite films were hydrophilic materials with water contact angles ranging from 55 degrees to 65 degrees. The results obtained from ELISA indicated the adsorption amount of fibronectin on composite films was much higher than on chitosan film. PC12 cells culture was used to evaluate the nerve cell affinity of materials. The cells cultured on the composite film with 60wt% gelatin differentiated more rapidly and extended longer neurites than on chitosan film. The results suggest that the soft and elastic complex of chitosan and gelatin, which has better nerve cell affinity compared to chitosan, is a promising candidate biomaterial for nerve regeneration.     

不同壳聚糖材料预防腹膜粘连的动物研究

为探讨不同壳聚糖材料对预防大鼠腹膜粘连的作用及机理,将240只大鼠分成两大组:壳聚糖凝胶组(A组)和壳聚糖/明胶共混膜组(B组)。A组144只随机分成3组,各组再分成对照组和实验组,用不同的方法致腹膜粘连,实验组用壳聚糖凝胶来预防粘连。B组96只,随机分成4组,每组24只,均行创伤法致腹膜粘连处理,其中1组为对照组,其余3组的创面分别用不同明胶含量的壳聚糖膜覆盖。术后2 w、4 w评定粘连程度并取相应组织作病理学检查。实验表明:(1)壳聚糖凝胶对创伤及缺血所致的腹膜粘连有明显的预防作用;(2)壳聚糖膜和壳聚糖/明胶共混膜都可加重腹膜粘连。     

Cross-Linking of Gelatin and Chitosan Complex Nanofibers for Tissue-Engineering Scaffolds

The aim of this study is to investigate cross-linked gelatin–chitosan nanofibers produced by means of electrospinning. Gelatin and chitosan nanofibers were electrospun and then cross-linked by glutaraldehyde (GTA) vapor at room temperature. Scanning electron microscopy (SEM) images showed that the cross-linked mats could keep their nanofibrous structure after being soaked in deionized water at 37° C. The cross-linking mechanism was discussed based on FT-IR results. The two main mechanisms of cross-linking for chitosan and gelatin–chitosan complex are Schiff base reaction and acetalization reaction. For gelatin, the mechanism of cross-linking was Schiff base reaction. The mechanical properties of nanofibrous mats were improved after cross-linking. The biocompatibility of electrospun nanofibrous mats after cross-linking was investigated by the viability of porcine iliac endothelial cells (PIECs). The morphologies of PIECs on the cross-linked nanofibrous mats were observed by SEM. In addition, proliferation of PIECs was tested with the method of methylthiazol tetrazolium (MTT) assay. The results indicate that gelatin–chitosan nanofibrous mats could be a promising candidate for tissue-engineering scaffolds.     

Performance modification of chitosan membranes induced by gamma irradiation

Trauma of the nervous system often results in permanent functional loss because the spontaneous regeneration of nerves is very difficult. Thus, various methods have been developed to facilitate the restoration of damaged nerve. The biodegradable nerve conduit is one of the most promising methods for nerve regeneration. Chitosan, a natural polysaccharide that has excellent biocompatibility and biodegradability, can be used as conduit material. But, nerves regenerated by nerve conduits made from chitosan have some problems, for example, with their mechanical properties. This article shows that the mechanical properties of chitosan film were markedly improved by selected doses of gamma radiation and cell culturing experiments on the surface of the irradiated chitosan film indicated that the film still has excellent biocompatibility.     

Efficient transfer of human adipose-derived stem cells by chitosan/gelatin blend films

Adipose-derived stem cells (ASCs) are a potential source of abundant mesenchymal stem cells and represent a promising cell-based therapy for tissue damage or degeneration conditions. Previous investigations have demonstrated enhanced therapeutic effects of ASCs in a three-dimensional spheroid culture formulation. In this study, we hypothesize that a composite membrane made of chitosan/gelatin (C/G) is beneficial to facilitate transfer of human ASCs in spheroids. Increasing chitosan content within the blends enhanced the mechanical properties of the sample, including tensile strength and elongation-at-break ratio. Although ASC spheroids developed shortly after seeding on pure chitosan films, increasing gelatin proportion in the C/G blends promoted cell adhesion onto the membranes. We also found that ASCs did not proliferate on chitosan films, but C/G blends of different ratios supported ASC proliferation in the first 4 days of culture. However, ASCs on all C/G blends started to detach from the films to form spheroids after day 4, while ASCs on pure gelatin films remained attached and continued to grow. Gradual gelatin release from the C/G blend films, leading to enriched chitosan content in the blends, probably encouraged ASC detachment and spheroid formation. We placed porous collagen matrix on ASC-seeded C/G blends to simulate the application of ASC-seeded C/G films onto injured tissue and found that a C/G film composed of 75% chitosan could facilitate significantly more cell transfer into the overlying collagen sponge. Therefore, a blend film containing 75% chitosan and 25% gelatin showed promising results to serve as a biomaterial for human ASC-based cell therapy.     

基于明胶膜基底捕获和原位培养循环肿瘤细胞

目前从血液中分离得到高活力的循环肿瘤细胞（CTCs）仍面临一定的挑战,本研究设计了一个明胶膜基底,可以同时实现捕获和原位培养CTCs。该明胶基底对CTCs的捕获效率最高可达86.8%。由于明胶具有良好的生物相容性,明胶膜基底在捕获到CTCs后可直接进行原位培养,减少了释放过程中对细胞的损害,有利于后续细胞分析。该明胶膜基底有望在临床CTCs检测中发挥作用。     

壳聚糖膜的降解与生物相容性研究

用小鼠作实验动物，研究了壳聚膜的生物降解与生物相容性，结果表明，壳聚糖膜易于生物降解，在植入初期有轻度炎症反应，至１６周后炎症反应基本消失。作为一种新型天然可吸收性生物材料，壳聚糖具有很好的发展应用前景。