Poly (vinyl alcohol) and its bacterial cellulose nanocomposites based tissue hybrid material

随着人口老龄化，对心脏瓣膜和血管移植物等心血管设备的需求稳步增加。这些器械的性能和耐用性通常受到所用材料性质的限制。虽然组织工程是有前途的，组织成分和功能特性的组织产生的尚未实现。因此，人们一直在寻找更好的替代材料。传统方法包括使用合成生物材料和经处理的动物组织，如机械和生物假体心脏瓣膜的情况。在动脉的情况下，只有大直径的合成替代品可用。对于冠状动脉置换术，必须使用患者的自体移植物。许多问题可追溯到组织和所用材料之间的机械不匹配以及材料缺乏血液相容性。在我们正在进行的两种生物材料，聚乙烯醇（PVA），生物相容性水凝胶和细菌纤维素（BC），在我们的实验室微生物发酵制成的纳米生物材料的研究中，我们已经证明，可以制备具有类似于主动脉组织的各向异性力学性能的PVA。通过添加BC纳米纤维，可以创建具有可以定制以模拟广泛的心血管组织的特性的各向异性PVA-BC纳米复合材料。我们建议设计各向异性PVA和PVA-BC生物材料，以具有靶心血管组织的力学性能。使用这些设计的生物材料作为基底，赋予组织中血液相容性的内皮细胞可以通过表面反应附着到基底上，以提供这些细胞的粘附位点。所得的各向异性PVA和PVA-BC的生物材料-组织杂化物将具有与邻近组织的良好机械相容性，同时由于与内皮细胞的融合表面覆盖而具有血液相容性。这些生物材料-组织混合物将适用于广泛的心血管置换器械。

There is a steady increase in the demand for replacement cardiovascular devices such as heart valves and vascular grafts as our population ages. Performance and durability of these devices are often limited by properties of the materials used. Although tissue engineering is promising, organization of components and functional properties of tissues generated are yet to be realized. Therefore there is a continuing search for better replacement materials. Traditional approaches include the use of synthetic biomaterials and treated animal tissues as in the case of mechanical and bioprosthetic heart valves. In the case of arteries, only large diameter synthetic replacements are available. For coronary replacements, autografts from the patient have to be used. Many of the problems have been traced to mechanical mismatch between the tissue and the material used and lack of hemocompatability of the material. In our ongoing study of two biomaterials, poly(vinyl alcohol) (PVA), a biocompatible hydrogel and bacterial cellulose (BC), a nano-biomaterial made by microbial fermentation in our laboratory, we have demonstrated that PVA with anisotropic mechanical properties similar to that of aortic tissue can be prepared. By the addition of the BC nanofibers, anisotropic PVA-BC nanocomposites with properties that can be tailored to mimic a broad range of cardiovascular tissues can be created. We propose to design anisotropic PVA and PVA-BC biomaterials to possess mechanical properties of the target cardiovascular tissue. Using these designed biomaterials as substrate, endothelial cells which impart hemocompatability in tissues can be attached to the substrate via surface reactions to provide adhesion sites of these cells. The resulting biomaterial-tissue hybrids of anisotropic PVA and PVA-BC would have good mechanical compatability with the neighboring tissue and at the sametime hemocompatabile due to confluent surface coverage with endothelial cells. These biomaterial-tissue hybrids would be suitable for use in a broad range of replacement cardiovascular devices.