Study On Hemocompatibility Of Diamond Like Carbon Film

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.