| Biomedical metallic materials play a vital role in the field of curing cardiovascular,orthopedic,and dental diseases.At present,there are many disadvantages of biomedical metal materials need to be improving,such as the release of metal ions and poor hemocompatibility.These defects not only decrese the stability of the metallic materials but also have negative influences on other body tissues.Mesoporous silica has good biocompatibility with high drug loading capacity,high surface area,and tunable pore size.In this thesis,mesoporous silica encapsulating various drugs was chosen as drug coating to modify biomedical metallic materials and the biocompatibility of obtained materials was carefully evaluated.The main research works are as follows:(1)Titanium alloy surface was modified by mesoporous silica with heparin.The sample had long-term release and high drug loading capacity.Hemolysis assay,platelet,whole blood cell attachment,morphological changes of red blood cells,and in vitro coagulation time were performed to assess hemocompatibility of modified titanium alloy.Vascular endothelial growth factor(VEGF)was introduced by specific interaction with heparin to induce endothelial cells proliferation,and the results were satisfactory.(2)Dopamine was selected to undergo oxidative self-polymerization under defined conditions,constructing a polydopamine layer on 316L stainless steel to provide rich amino group creating a positively charged surface.Mesoporous silica could be bonded to the polydopamine layer on the basis of electrostatic interaction.Heparin and rapamycin were selected as drug models.The sample was characterized in detail by scanning electron microscope,transmission electron microscopy,fourier transform infrared spectroscopy,water contact angle,and so on.It had long-term release and high drug loading capacity.Through testing of sample,the results showed that the modified sample had a good biocompatibility.(3)Mesoporous silica which loaded vancomycin and heparin were coating on titanium alloy surface.The sample was characterized in detail by scanning electron microscope,transmission electron microscopy,fourier transform infrared spectroscopy,water contact angle,and so on.It had long-term release and high drug loading capacity.By bacterial adhesion,osteoblast proliferation and apoptosis rate experiments indicated that the modified sample could resist bacterial adhesion and promote osteoblast proliferation by specific binding of heparin and SDF-1α.In vivo experiments also demonstrated that the antibacterial activity of the modified implant was improving. |
