Immobilization Of Chiral Cystine On Ti-O Surface And Investigation On Its Generation Of Nitric Oxide And Endothelial Cell Biocompatibility

The levels of biological systems have the typical characteristics that different chiral molecules always have various biological functions:The S-S bond within Cystine molecules can catalytic NO donor to releases NO. In this paper, the effects of the chiral surface on catalyzing to release NO were investigated by grafting the chiral cystines, L-cystine and D-cystine on the film surface of Ti-O.Firstly, Ti-O films on the surface of single-crystal silicon were fabricated by unbalanced magnetron sputtering technique and then poly-dopamine was deposited on the surface of Ti-O films. Lastly, the chiral cystines were grafted on poly-dopamine surface.X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), water contact angle etc. were used to characterize modified material surface. Catalyzing to release NO in vitro experiments was used to value the catalytic ability of the chiral cystines and endothelial cell culture in vitro experiments were used to study the effect of the chiral cystines on the biological traits.XPS results show that polydopamine is successfully deposited and form a uniform dense film by means of AFM on the surface of Ti-O film. Further, AFM results reveal that the sample surface roughness increases resulting from dopamine polymerizing to polydopamine. After the chiral cystines were drafted on the dopamine, the sample surface roughness has no change. According to the XPS results the chiral cystines were successfully grafted on dopamine surface and the amount of L-cystine and D-cystine on the grafted dopamine surface is almost coincident. Water contact angle test results show that the hydrophilicity of Ti-O surfaces increases by depositing dopamine and that the chiral cystines were drafted leads to the increasement of the hydrophilicity on sample surfaces. The point is that the hydrophilicity of L-cystine surface is the same as the D-cystine because of the same physical properties. After the chiral surfaces absorbed albumin, the sample surface hydrophilicity make a difference for L-cystine and D-cystine and the reason is possible the effect of albumin absorption.Catalyzing NO donor to release NO experimental results show that the chiral cystines can stably release NO and the rate of L-cystine catalyzing to release NO is greater than the D-cystine. Culturing statically endothelial cells in vitro experimental results show that regardless in the presence or absence of NO donor, the adhering and the proliferation content and migration distances of endothelial cells on L-cystine sample surface are higher than the D-cystine. The samples are treated through fetal calf serum and the results show that the proliferation of ECs on L-cystine are obviously higher than the D-cystine and Ti-O. Catalytic chamber experiments in the presence of NO donor reveal that with time extension nitrate and nitrite content in endothelial cell culture medium with L-cystine is higher than that with D-cystine. In conclusion, it is notable differences that the sample surfaces through drafting chiral cystines, L-cystine and D-cystine, on Ti-O film is of in biological properties.