Development Of Nano-films Of Thromboresistance And Study On Its Mechanism Of Blood Compatibility

Amorphous carbon films with different microstructures, La2O3 doped Diamond-like carbon (DLC) films and TiO2 films with La doping different concentration were deposited by using pulse laser ablation and Radio-Frequency magnetron sputtering, respectively. The characters of films, such as microstructure, surface properties, optical & electronic properties and wettability, were investigated and the haemocompatibility of various films was evaluated by in-vitro tests. The influence of pulse repetition rate and pulse energy on the structure and the properties of the ta-C films are investigated and the control of sp3C content in the films is realized. Methods to adulterate biomaterials with rare earth are proposed. La2O3 doped DLC films with good blood compatibility were prepared and the effect of sp2 bonds and La2O3 on the haemocompatibility of DLC films were discussed. La2O3 doped TiO2 films with good blood compatibility were prepared and the effect of La2O3 on the microstructures and haemocompatibility were investigated. The thromboresistance mechanism of biomaterials was studied by means of molecular dynamics simulation methods. The systemic energy and interactive energy of fibrinogen with La2O3-doped TiO2 films were calculated and a selective adsorption model is introduced and applied to explain the result of experimentation. The interaction behavior at the interface between the biomaterial films and the plasma proteins was investigated using the biochemistry examinations.Firstly, the influence of pulse repetition rate and pulse energy in pulse laser ablation on the structures and the properties of the ta-C films have been studied. The wettability and blood-compatibility were investigated. Results show that the electronic structure of ta-C films plays a significant role in haemocompatibility compared with its property of surface.Secondly, La2O3 doped Diamond-like carbon (DLC) films with different concentrations were deposited by using Radio-Frequency magnetron sputtering. The effects of La2O3-dopant on the microstructure, surface properties, optical & electronic properties and wettability of DLC films were investigated. Results show the sp2-bonded C content increases and the band gaps of films decrease from 2.1eV to 1eV with increasing of La2O3 concentration doped. In the same temperature, the carrier concentration increases with increasing La2O3 addition. La2O3 addition has a suppressive effect on the crystal growth of DLC in process of deposition and the hydrophilicity of films decreases with the increase of content of La2O3-doped in the films. The polar component is critical to the change of the surface energy of doped films and the La2O3 doped DLC films have the good blood compatibility.Thirdly, keeping the contents of La3+ in the films and changing the temperature of substrate, the effects of temperature deposited on structure and haemocompatibility of La2O3 doped DLC films were investigated. Results show that the sp2-bonded C content increases with the increase of the temperature of substrate. The surface energy of films change slightly and the interfacial energy decreases with the temperature rising and the films are inclined to adsorb fibrinogen which shows the effect of sp2 bonds and La2O3 on the haemocompatibility of DLC films is different.Fourthly, La2O3 doped TiO2 films with different concentration were deposited by using Radio-Frequency magnetron sputtering. The effects of La2O3-dopant on the microstructure, surface properties, optical properties and wettability of TiO2 films were investigated. Results show La2O3 addition has a suppressive effect on the crystal growth of TiO2 in process of deposition. The band gaps of films increase from 2.85eV to 3.3eV with increasing of La2O3 concentration doped from 1.56% to 3.64% and the hydrophilicity of films increases with the increase of content of La2O3-doped in the films. Doped TiO2 films reveal unique haemocompatibility compared with un-doped films. The selective adsorption of La2O3-doped TiO2 films for the fibrinogen and serum albumin of the blood plasma and suitable electronic structure are believed to the main factor responsible for the good blood compatibility.Finally, according to the result of experimentation, the systemic energy and interactive energy of fibrinogen with La2O3-doped TiO2 films were calculated by means of molecular dynamics simulation methods and a selective adsorption model is introduced and applied to explain the result of experimentation. The thromboresistance mechanism of biomaterials was studied ulteriorly by Lewis acid-base theory about solid surface adsorption. Results also proved that films with the wide band gap structure or Lewis base (electron donor) surface may block the electron transfer through the interface from fibrinogen, retain the conformation of fibrinogen and inhibit the activation of the blood coagulation function.