Preparation And Characterization Of Cu-doped TiO₂ Thin Films And Their Effects On Biocompatibility

Nitric oxide(NO)is an important cellular messenger molecule for regulating the cardiovascular system.Some important physiological functions of NO are vasodilation,neurotransmission,immune regulation,cardiac contractility,inhibition of platelet adhesion,activation and inhibition of smooth muscle cell proliferation.In recent years,NO has been used for the treatment of cardiovascular diseases.A large number of literatures suggest that NO donating/producing materials could improve the anticoagulant and anti-proliferative properties of the materials by releasing NO.In this dissertation,sol-gel method has been used to construct films doped copper with catalytic activity.The thin films could catalyze endogenous NO donor in situ and let it release NO to improve the anticoagulation and anti-hyperplasia.Different amounts of copper doped TiO2 thin films has been prepared on the silicon wafer by adjusting the molar ratio of titanium and copper.TiO2 has good biocompatibility and NO could be catalyzed by copper.The thin films could produce NO in vivo which is similar with endothelial cells.So the biocompatibility of the materials could be significantly improved.The catalytically active layers were characterized by atomic force microscope(AFM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and water contact angle measurement(WCA).It was found that with the increase of copper,the surface roughness and water contact angle increased.XRD results showed that all the films consisted of anatase TiO2.XPS results showed that with the amount of copper increasing,Cu2O changed to CuO gradually.The catalytic properties were evaluated by NO release experiments in vitro,and the results showed that the films with 5%and 10%copper(sample Cu3 and Cu4)have the strongest ability to release NO.The platelet adhesion and activation experiments,smooth muscle cell adhesion and migration experiments and endothelial cell culture were also performed in this study.It was found that Cu3 and Cu4 not only inhibited platelets adhesion and aggregation,but also inhibited the adhesion and migration of smooth muscle cells.Cu3 and Cu4 had no adverse effect on endothelial cells.The anti-inflammatory and antibacterial ability of the copper were also evaluated by macrophage culture and Escherichia coli culture,respectively.The copper doped films had better anti-inflammatory property and better anti-bacterial property than TiO2 thin films without copper.In this dissertation,the catalytically active layers have been constructed on the silicon wafer by sol-gel method.The layers could induce the endogenous donor to release NO in situ,inhibit platelet adhesion and activation and smooth muscle cell attachment and proliferation.Additionally,the films also have the ability of anti-inflammation and anti-bacteria.