Study On Adsorption And Competive Adsorption Of Plasma Proteins Onto The Surfaces Of Biomaterial

Protein can be spontaneously adsorbed onto any solid surface, which was discovered very early and has wide use in biomedicine, biomaterial and bioengineering fields. The adsorption and competive adsorption of plasma proteins was the first phase of the whole blood coagulation process when materials contacted with boold. And this adsorption layer was main reaction site between blood and materials. The variety and quantity of adhesion protein on biomaterials determine following platelet adhesion and thrombokinesis reaction, but these are affected by the surface property of biomaterials. So the research of plasma protein adsorption behavior is significant in biocompatible materials. The research not only will be conducing to understand anticoagulation mechanism of biomaterial, but also to guide our study for new biomaterial's design.We investigated the adsorption and competive adsorption of plasma proteins on PEU-LCP composite biomaterial surface by fluorescent quantitative analysis. The main experiments and results were as follows:(1) Bovine serum albumin(BSA)and bovine plasma fibrinogen (Fg)were fluorescent labelled with fluorescein isothiocyanate(FITC). FITC-BSA and FITC-Fg fluorescence standard curve was obtained. The experiment results showed that labelled protein was very stable under specified temperature. Labelling did't affect adsorption behavior.(2) The isothermal adsorption process of the protein solution with single component on PEU-LCP composite material surface was researched. BSA adsorption quantity and Fg adsorption quantity of PEU-LCP composite material surface were decreased when the environmental temperature rised. The maximal adsorption density of BSA and Fg of PEU-LCP composite material surface were 1.6328μg/cm2 and 0.2583μg/cm2. The adsorption heat between BSA and materials was -6.424 kJ/mol, and the adsorption heat between Fg and materials was -4.384 kJ/mol. The results showed that the adsorption of BSA and Fg on PEU-LCP composite material surface were not only mono-molecular layer adsorption, but also were physical adsorption.(3) The adsorption equilibrium of BSA and Fg on PEU-LCP surface were fitted with Langmuir model and Freundlich model. On the base of the data, we obtained adsorption equilibrium model equation for BSA and Fg under different temperature.These confirmed albumin and fibrinogen isothermal adsorption could describe by Langmuir adsorption model.(4) Single composition protein adsorption dynamics onto the surfaces of PEU-LCP composite was investigated. Along with the protein initial concentration increased, BSA and Fg adsorption quantity on composite surface alse increased, and then the adsorption tended to equilibrium. By using a progressive approach computing method, the complicated kinetics equation was solved. The rate constants of adsorption, desorption and transform of BSA and Fg were estimated .(5) BSA-Fg binary protein system competition adsorption onto the surfaces of PEU-LCP composite was investigated. The results showed that Fg was more capable of competitive adsorption than BSA on the surfaces of PEU-LCP composite. The binary protein competition adsorption model was established.