The Biocompatibility Of Carbon And Nitrogen Membrane And Ion Implantation Of Surface Modification Of Polypropylene

Preliminary studies have been shown that diamond-like carbon (DLC) had a great potential as a durable, wear and corrosion-resistant coating for biomedical implants. Surprisingly, carbon nitride (CNX) has not received much attention recently in the biomedical field, despite its performance comparable to or greater than that of DLC In this study, CNX and DLC coatings were prepared using the standard dc magnetron sputtering at room temperature. The structure tests showed that N2 partial pressure could change the percent of sp^C in CNX coatings The effects of CNX and DLC coatings on mouse fibroblasts and human endothelial cells were determined by scanning electron microscopy. Properties of hemocompatibility, including coagulation time and platelets adhesion, were also investigated. The results showed that the coatings displayed good hemocompatibility and caused no adverse effects on cells in vitro. CNX coating provided a comparable to or better surface than DLC for the normal cellular attachment, growth and morp hology. Compared with DLC, CNX coating also exhibited higher hardness, lower coefficient of friction, lower roughness, and lower corrosion, which obviously contributed to more sp3C structure and indicated a longer wear and corrosion life for CNX coating. These results support the biocompatibility of CNX and DLC and should initiate an interesting to the biomedical applications of CNX coating.Another work of this thesis is the surface modification of polypropylene by Carboxy ion (COOtT) implantation. Carboxy ion (COOH") was performed at an energy of SOkeV with fluences ranging from IxlO14 to IxlO15 ions/cm2 at room temperature. The effects of COOH+ implantation on cells (murine macrophages, 3T3 mouse fibroblasts and human endothelial cells) were studied in vitro. Properties of hemocompatibility, including coagulation time, recalcification time, were also investigated. The results showed that the modified surface of PP displayed good hemocompatibility and caused no adverse effects on cells in vitro. Tests of cell attachment gave interesting results. The 3T3 mouse fibroblasts and human endothelial cells cultured on the surface of the implanted PP showed much better attachment and proliferation than that for controlled PP. At the same time, the COOFT ion implantation also exhibited low macrophage attachment with normal cellular morphology. The above results can cause positive effects on the biocompa tibility when it is used as implant material. In order to probe the reason of the obvious improvement in the biocompatibility of implanted PP, the surface chemical structurewas characterized. Results showed that COOH+ ion implantation caused the formation of some new O-containing groups, which was responsible for the enhancement of the biocompatibility of PP.