【作者】 李伯刚；

【导师】 郑昌琼；

【作者基本信息】 四川大学 ， 生物医学工程， 2004， 博士

【摘要】 生物材料的血液相容性机制和用表面界面性能表征、评价生物材料的血液相容性，是生物材料研究的前沿课题。 本论文以类金刚石薄膜（Diamond like carbon film,DLC）为材料样本，用金刚石薄膜（Diamond film，DF）、石墨作参比材料，采用放射性同位素¹²⁵I标记技术，研究了白蛋白（Albumin，Alb）、纤维蛋白原（Fibrinogen，Fg）、免疫球蛋白（Immunoglobin，IgG）3种血浆蛋白在3种材料表面单一蛋白的吸附动力学、等温吸附和二元蛋白的竞争吸附，并依据透射红外光谱辨析吸附蛋白与材料间有无氢键作用：通过扫描电子显微镜（SEM），观察、分析了3种材料表面血小板的黏附量和黏附血小板的变形度；利用X光电子能措（XPS），分析了各种DLC试样的碳相组成；借助标准液体在材料表面的平衡接触角，测定了不同碳相组成DLC的表面能量参数。在此基础上，运用灰色系统理论中的T型关联度分析法，探讨了碳相成分对DLC蛋白吸附特性和血小板黏附特性的影响、表面（界面）能量在DLC血小板黏附中的作用和碳相成分影响DLC血液相容性的能量机制。最后，通过DLC、DF、石墨、低温各向同性碳（Low temperature isotropic carbon，LTIC）、含硅碳膜（Si：DLC）、碳化硅（SiC）6种有代表性生物碳素材料体外动态凝血时间（Kinetic clotting time，t_k）、溶血率（Hemolysis，α）、血小板消耗率（Platelet consumption，η）三个血液相容性指标实际检测结果和表面能量参数测定数据基础上的T型关联度分析，检验了用表面（界面）能量表征、评价生物碳素材料血液相容性的可行性。结果表明： （1） 由于存在氢键相互作用，DLC对Alb的吸附量明显高于DF，而DF对Fg、IgG，石墨对Fg都表现出了更高的吸附活性；DLC对三种血浆蛋白的吸附是非特异性的，DF则优先吸附Fg、IgG，石墨优先吸附Fg。 （2） 在DLC的5种碳相成分中，类金刚石碳相具有增进Alb吸附、抑制Fg、IgG吸附的双重功效，其对DLC蛋白吸附的影响远大于其它碳相成分;随着类金刚石碳相的减少和其他杂质碳相的相应增加，DLC对Alb的吸附能力下降，对Fg、IgG的吸附活性增强，蛋白吸附特性也由对3种蛋白的非特异性吸附逐渐转变为优先吸附Fg、IgG。 （3）蛋白吸附介导的血小板薪附与变形，是生物碳素材料的主要凝血机制。 （4）由于具有优化DLC蛋白吸附特性的作用，类金刚石碳相的增加会抑制血小板的薪附和变形，纯类金刚石相DLC甚至不勃附血小板;而C一H相和C一O相则会促进薪附血小板的变形，从而对DLC的血液相容性产生负面影响。可采用对类金刚石碳相提出含量保证要求、对C一H、C一O杂质碳相进行含量限定的形式设立标准，对DLC进行血液相容性评价。 （5）生物碳素材料的血液相容性取决于其表面的亲水性和有限润湿的平衡，存在一个以临界表面张力为指标的血液相容性区域。可用临界表面张力表征和评价生物碳素的血液相容性。 从而揭示了DLC等生物碳素材料的凝血机制、血液相容性原理和表面因素 （表面成分和表面能量）对血液相容性的影响规律，找到了用表面界面性能表征、评价DLC和其他生物碳素材料血液相容性的途径和方法，并通过了可行性检验。为DLC面向人工机械心脏瓣膜（AMHV）涂层材料的研制、开发和应用奠定了坚实的理论基础。 由此可见，本论文基于蛋白吸附（分子水平）、血小板猫附（细胞层次）和血液相容性指标（宏观方面）不同层次，从特性表现、碳相成分的影响屯表面（界面）能量的作用不同方面，及以DLC为核心、兼顾其他碳素材料的全方位研究，是成功和卓有成效的。关键词:类金刚石薄膜血液相容性 血桨蛋白吸附血小板猫附表面界面性能人工机械心脏瓣膜灰色关联分析更多还原

【Abstract】 In the present dissertation, the adsorption of human serum albumin(Alb), human serum fibrinogen(Fg) and human serum immunoglobin(IgG), the adsorption kinetics, the isothermal adsorption and the competitive adsorption of binary protein system, on the surfaces of diamond like carbon film(DLC), diamond film(DF) and graphite were investigated by radio isotope 125I labeling method, furthermore FT-IR-ATR spectra of the three proteins adsorbing on surfaces of the three materials were analyzed to clarify if hydrogen bonds exist on the interface of the proteins and the materials; Morphology observation, counting and deformation index calculation of the platelets adhering to surfaces of the three materials were carried out by SEM; Carbon phase components of DLC samples were analyzed by XPS; Surface energy parameters of DLC samples were calculated by determining balanced contact angle of ethanol, water and different ratio of ethanol/ water solution on surfaces of the samples.Then, the effects of carbon phase components on protein adsorption and platelet adhesion, the effects of surface energy on platelet adhesion, and energy mechanism of effects of carbon phase components on hemocompatibility for DLC were studied by using the analysis of T-type correlation degree in the Grey system theory.Finally, the feasibility of characterizing and evaluating the hemocompatibility of carbonaceous biomaterials by surface energy was tested by using the analysis of T-type correlation degree within hemocompatibility indexes, such as kinetic clotting time, hemolysis, platelet consumption, and surface energy parameters of the representative ones in caobonaceous biomaterials such as DLC, DF, graphite, LTIC, Si:DLC and SiC,.It has been shown from results that:(1) the adsorptive amounts of Alb on DLC are more than those on DF, while the adsorptive activity of Fg on DF and graphite, and IgG on DF are apparently more than that on DLC, for the action of hydrogen bond; there is no apparent distinction for the adsorption of the three proteins on DLC, but the adsorption of Fg, IgG on DF, and Fg on graphite takes precedence in varing degrees.(2) in five kinds of carbon phase component, diamond like carbon phase has both effects of enhancing adsorption for Alb and weakening adsorption for Fg and IgG, thus its influence on the adsorption protein for DLC is much more important than that of other phase components; with decreasing diamond like carbon phase and increasing foreign phase, the adsorptive amounts of Alb on DLC decrease, but those of Fg and IgG greatly increase, furthermore, original character that there is no apparent difference for the adsorption of three human serum proteins on DLC also turns into Fg and IgG apparently have the advantage of Alb.(3) adhesion and deformation of platelets occurred in succession on material surfaces resulting from protein adsorption are the major mechanism of blood coagulation of carbonaceous biomaterials.(4) diamond like carbon phase possesses actions of inhibiting adhesion and deformation of platelet to DLC for its both effects of enhancing adsorption for Alb and weakening adsorption for Fg and IgG, so that, there is no any platelets on the surface of pure DLC; but C-H phase and C-0 phase possess promoting action on deformation of the platelets adhered to the surface of DLC. thus the hemocompatibility of DLC can be evaluated by using the content of DLC phase and additional content limitation of C-H phase and C-0 phase as standard.(5) the hemocompatibility of carbonaceous biomaterials is decided by balance between polarity of their surfaces and limited humidification of water on the surfaces, there exist an blood compatible range delimited by critical surface tension. Therefore, the hemocompatibility of carbonaceous biomaterials can be characterized and evaluated by the critical surface tension.These conclusions have provided theoretical basis for research and prepare ofDLC having the best quality applied to AMHV.更多还原