ePTFE人工血管管壁结构及其体外性能的试验研究

对国内外两组膨体聚四氟乙烯(ePTFE)人工血管从管壁结构、理化性能和生物力学性能进行对比研究.通过试验研究两组人造血管管壁的宏观及微观结构、表面润湿性、结晶度和融熔温度、周/轴向拉伸、顶破拉伸以及手术线固位强力,对比两组样品的性能差异,并分析了导致差异的可能原因,讨论了管壁结构、理化性能与力学特性之间的关系.研究结果表明,国产和进口ePTFE人工血管试样均为双层结构,两者都有良好的疏水性表面和抗水渗透性.但进口试样具有更加规整均匀的节点和纤维形态结构,有利于人工血管的生物耐久性.     

Promoted Cytocompatibility of Silk Fibroin Fiber Vascular Graft through Chemical Grafting with Bioactive Molecules

Natural silk from Bombyx mori has been used as medical sutures for several decades,and regenerated silk fibroin( RSF)based biomaterials have been increasingly studied in the past thirty years. However,vascular graft derived from silk fibroin fiber has been explored in recent several years with development of textile science and engineering. Moreover,endothelialization of vascular graft has been seen as an ideal strategy for preventing thrombosis and getting higher patency in a long term. Therefore,in the present work silk fibroin fiber vascular graft( SF) was chemically grafted with bioactive molecules such as heparin and RSF to improve the cytocompatibility. 3-aminopropyl-triethoxysilane(APTES),1-ethyl-3-(3-dimethylaminopropyl) carbodiie hydrochlide( EDC · HCl),and N-hydroxysuccinimide( NHS) have been employed as coupling agent and crosslinking agents,respectively. Microscopy and ATRFTIR were used to characterize the surface changes and the structure of the grafts after treatment,respectively. Cell culture in vitro and MTT assay were conducted to determine the improvement of cell affinity to the graft. Furthermore,mechanical properties of the grafts before and after treatment were compared. The results showed that the chemical grafting was an effective method for improving the cytocompatibility of SF without significant loss of mechanical properties.     

纺织基人工血管的水渗透性

选用丝素和涤纶(PET)材料,分别制备了平纹和斜纹人工血管,测试并分析了在16kPa条件下,材料性质、组织结构、水浸润时间对人工血管水渗透性的影响.结果表明,在16kPa压强下,连续测量60min,无浸润丝素平纹人工血管的水渗透性呈现先快速下降而后平稳的变化趋势,而无浸润涤纶平纹人工血管的水渗透性变化不明显;两种斜纹人工血管的水渗透性远远高于平纹组织;随着浸润时间的延长,丝素平纹人工血管首分钟水渗透量显著降低,而涤纶平纹人工血管变化不明显.     

pH响应型医用抗菌水凝胶人工血管材料

基于互穿网络结构的聚乙烯醇/聚丙烯酰胺水凝胶，运用抗菌肽制备了一种pH响应型抗菌水凝胶人工血管材料。试验结果表明，该水凝胶表面光滑、微孔结构均匀，力学性能优良且具有低体积溶胀性。体外细胞毒性试验和抗菌试验结果表明，该水凝胶在生理状态下不具备杀菌性能和细胞毒性，而在低pH值环境下对大肠埃希菌与金黄色葡萄球菌都具有明显的杀菌作用。研究结果为进一步开发响应型抗菌水凝胶人工血管提供了理论和试验依据。     

舌根疣状黄瘤一例

疣状黄瘤是一种较罕见的主要发生在口腔粘膜的良性病变,发生于舌根者尤为罕见.现报告一例如下:     

聚乙烯醇/聚丙烯酰胺水凝胶基小口径人工血管材料

结合浇注法及编织法制备了一种编织管增强的聚乙烯醇(PVA)/聚丙烯酰胺(PAAm)水凝胶小口径人工血管材料(内直径6 mm),并进行了一系列表征。结果表明:当该人工血管材料的拉伸伸长率为50%时,拉伸强度可达到(905.6±63.1)kPa,压缩弹性回复率为(93.4±6.7)%,缝合线固位强力为(9.89±0.64)N;在80~120 mmHg条件下,径向顺应性达到(3.11±0.09)%,是商用e-PTFE人工血管的6.9倍;材料的细胞相容性良好,溶血率极低,属于不溶血材料。     

层层组装法改善丝素人工血管材料生物相容性

为改善丝素纤维人工血管材料(SFF)的生物相容性,拓展其在小口径人工血管领域的应用,采用层层组装法(LbL)在SFF表面构建再生丝素蛋白(RSF)和壳聚糖(CHI)多层膜,表征组装前后材料的元素组成和亲疏水性以及组装膜形貌、厚度和粗糙度,并进行生物相容性评价。结果表明:通过LbL法可在SFF表面成功构建(RSF/CHI)n多层膜;组装(RSF/CHI)8的SFF在1、3、5d的细胞增殖率分别为未组装SFF的1.64、2.82和4.45倍;组装(RSF/CHI)8的SFF的溶血率约为未组装试样的1/3。生物相容性试验表明,组装(RSF/CHI)8的SFF的体外细胞和血液相容性均得到显著改善。     

编织管增强的海藻酸钙/聚丙烯酰胺水凝胶人工血管材料制备及性能分析

自主设计了管状器官浇注成型模具,以海藻酸钠及丙烯酰胺为原材料,涤纶单丝编织管为增强基,制备出了互穿网络结构的编织增强水凝胶人工血管材料。研究了Ca~(2+)溶液作用时间对水凝胶体积溶胀率和拉伸断裂强度的影响,同时对管状水凝胶材料的拉伸性能、压缩性能、缝合线固位强力以及径向顺应性等进行了表征。研究表明,Ca~(2+)溶液作用的最佳时间为5h,获得水凝胶SP_3。利用SP_3水凝胶和编织管道制备的复合水凝胶管成型良好,不发生明显的体积溶胀,且力学性能优良,具有作为移植用人工血管的潜力。     

Computer Simulation of Random Packing of Spherical Particles in Two Dimensions

Random packings of spherical particles have attracted attention for many years.An algorithm based on compression is developed to generate random packings of spherical particles in this paper.This method is different from previous compression-based algorithm.In order to increase the packing density,a process of shaking is applied during packing process.The algorithm is mainly composed of three procedures:generating initial packing configuration by using random sequential adsorption(RSA),compressing packing d...     

Preparation and Mechanical Performance of Blended Polyester/Silk Small Diameter Arterial Prostheses

Small diameter arterial prostheses were required to treat coronary and cerebrovascular arterial diseases. The diameters of the artificial blood vessels should match the diameters of the host arteries. Besides,the mechanical properties of the arterial prostheses should be strong enough to endure the forces in the body after implantation. In this study,silk and polyester were woven into small diameter arterial prostheses and the dimensional and mechanical properties,as well as the water permeability,were investigated. The woven samples had an inner diameter ranging from 3. 65 to 3. 94mm. The wall thickness of the samples ranged from 0. 26 to 0. 28mm. Compared with polytetrafiuoroethylene( ePTFE) commercial devices,whose probe bursting strength was measured to be 15. 64 N /mm2,the woven samples had superior strength values ranging from20. 53 to 28. 97 N /mm2. In addition,the radial compliance of the woven samples was found to lie between the ePTFE sample and the pig’s carotid artery,and the water permeability of all the woven samples was less than 300 mL /( cm2·min) which indicated that these woven samples could be implanted without preclotting.