The Surface Topology Modification On Biomedical Titanium And Its Effects On Biocompatibility

Titanium(Ti)and its alloys have been widely used in bone substitute materials due to their good mechanical properties,corrosion resistance and excellent biocompatibility.However,most of the Ti and its alloys used in clinical practice are still bio-inert materials.Its insufficient osseointegration and lack of biofunctionality.Which may leads to loosening and even falling off of the implant,poisoning,infection,inflammatory reaction,degradation or absorption of bone tissue function,and so on.Natural bone has highly organized hierarchical structures of micron-scale haversian osteon and nanoscale collagen fibers as well as hydroxyapatite crystals.Therefore,the ideal bone implant should be composed of micro-to-nano-scaled hierarchical structure from the view of bionics.In order to improve the osseointegration of Ti and its alloys,one of the key problems in the development of new bone substitute materials is the design and manufacture of Ti-based implants with human-like bone structure.In this paper,selective laser melting(SLM)and electrochemical anodic oxidation were used to prepare dense Ti-6Al-4V with hierarchical composite structure.The properties of the samples were studied by scanning electron microscope,three-dimensional laser scanning microscope,contact angle measuring instrument,fluorescence microscope and enzymatic marker.It was found that the hierarchical composite structure of SLM-TNT had better hydrophilicity and biocompatibility,which was more helpful to the adhesion,proliferation and differentiation of rat bone marrow mesenchymal stem cells(rBMSCs).The titania nanotubes(TNT)on Ti and its alloy is mostly focused on the study of bone integration ability,but it has not been found in the bone tumor treatment.Osteosarcoma is a common malignant tumor in adolescents,with the characteristics of high mortality,high recurren ce rate and difficulty in thorough treatment,which are usually treated through surgical implantation and chemotherapy with greater toxic and side effects.In this paper,in order to address these problems,a new type of antitumor medical Ti implants with pH response that could provide a higher concentration of anticancer drugs locally to treat bone cancers and reduce the recurrence rate of osteosarcoma in situ.The implants were fabricated by an anodization process featuring TNT arrays.Doxorubicin(DOX)was loaded into TNT by dripping,and the surface of implants was covered with ZnO-FA coating.The surface properties of the samples were studied by fourier transform infrared spectroscopy and scanning electron microscope.Drug release and in vitro indirect culture study showed that doxorubicin(DOX)molecules could be released slowly in TNT and had pH response.The direct culture was convinced that the weak acidic environment around tumor tissue can promote the release of antitumor drugs in TNT,killing the cancer cells accurately,reducing damage to normal cells,improving the survival rate of patients with recurrent osteosarcoma.