Surface Desigh of Polymers by Using Photochemistry of Dithiocarbamate For the Control of Bioreaction

为了研究蛋白质与末端接枝聚合物表面之间相互作用力的特性，使用原子力显微镜测量了蛋白质固定探针尖端（白蛋白和溶菌酶）与水溶液中N，N-二甲基丙烯酰胺或丙烯酸接枝聚合物表面之间的力-距离曲线（f-d曲线）。通过观察到的f-d曲线，分别分析了接枝链长度、接枝密度和接枝链段的静电强度对蛋白质在接枝聚合表面吸附和解吸过程中相互作用力的影响。接枝状态影响蛋白质的粘附特性，在生理ph下，聚阴离子表面不仅对带正电的蛋白质提供了显著的粘附力，对带负电的蛋白质也提供了显著的粘附力。利用体内组织工程技术制备了更多的血管样管状组织，并对其力学性能进行了评价，以期作为小口径人工血管假体应用。将聚乙烯（PE）、聚氟乙酸酯（PFA）、聚甲基丙烯酸甲酯（PMMA）、聚氨酯（PU）、聚氯乙烯（PVC）和硅酮（Si） 6种聚合物棒作为模具植入新西兰大白兔背部皮肤的6个皮下袋内，制备生物管。对于除PFA外的棒，在植入1个月后通过在聚合物植入物周围包封构建生物管。根据植入材料的不同，生物管的壁厚在50 ~ 200 μm之间，排列顺序为PFA<PVC<PMMA<PU<PE。PE、PMMA、PVC在植入3个月后厚度增加1.5 ~ 2倍。当静水压力逐渐施加到管腔达到200mmhg时，没有一个生物管破裂。腔内压力与外径的关系与原动脉相似，呈“J”型曲线，重现性强。组织主要由富含胶原的细胞外基质和成纤维细胞组成。一般来说，Si的组织相对坚硬无弹性，PMMA的组织相对柔软。PMMA、PE和PVC生物管的刚度参数分别与人冠状动脉、股动脉和颈动脉相似。生物管在其基质、力学、形状和管腔表面设计上具有广泛调整的能力，可以应用于小口径血管，并且由于它们避免了免疫排斥反应，是一种理想的植入物。少

To investigate the characterizatics of interaction forces between proteins and end-grafted polymer surfaces, force-versus-distance curves (f-d curves) were measured between protein-fixed probe tips (albumin and lysozyme) and surfaces graft-polymerized with N,N-dimethylacrylamide or acrylic acid in an aqueous solution, using an atomic force microscope. The effects of grafted chain length, grafting density, and electrostatic properly of the grafted chain segments on the interaction forces in the processes of protein adsorption onto and desorption from the graft-polymerized surfaces were analyzed from the approaching and retracting traces of he observed f-d cures, respectively. The grafting state affects the adhesion characteristics of the protein and a polyanionic surface provides a significant adhesion force not only to a positively charged protein but also to a negatively charged one at physiological pH.On the other hand, vascular-like tubular tissues named biotubes consisting of autol … More ogous tissues were prepared using in vivo tissue engineering and their mechanical properties were evaluated for application as a small caliber artificial vascular prosthesis. The biotubes were prepared by embedding six kinds of polymeric rods (poly(ethylene)(PE), poly(fluoroacetate)(PFA), poly(methyl methacrylate)(PMMA), segmented poly(urethane)(PU), poly(vinyl chloride)(PVC) and silicone (Si)as a mold in six subcutaneous pouches in the dorsal skin of New Zealand White rabbits. For rods apart from PFA, biotubes were constructed after 1-month of implantation by encapsulation around the polymeric implants. The wall thickness of the biotubes ranged from about 50 to 200 μm depending on the implant material and were in the order PFA<PVC<PMMA<PU<PE. As for PE, PMMA, and PVC, the thickness increased after 3-month of implantation and ranged from 1.5 to 2 fold. None of the biotubes were ruptured when a hydrostatic pressure was gradually applied to their lumen up to 200 mmHg. The relationship between the intraluminal pressure and the external diameter, which was highly reproducible, showed a 'J'-shaped curve similar to the native artery. The tissue mostly consisted of collagen-rich extracellular matrices and fibroblasts. Generally, the tissue was relatively firm and inelastic for Si and soft for PMMA. For PMMA, PE and PVC the stiffness parameter of the biotubes obtained was similar to those of the human coronary, femoral and carotid arteries, respectively. Biotubes which possess the ability for wide adjustments in their matrices, mechanics, shape and luminal surface design can be applied for use as small caliber blood vessels and are an ideal implant since they avoid immunological rejection. Less