Surface Modification Of Titanium Substrates And Their Biological Evaluations

Ti and its alloys have been widely used as orthopedic fields, dental implant and plastic surgery, due to their good biocompatibility and mechanical property. Despite these excellent properties, bacterial infection and poor osseo-integration of Ti and its alloys may lead to implant failure. In this study, surface functionalization of Ti and its alloys is used to promote osteoblast growth and reduce bacterial infection. The main contents of study are listed as follows:(1)The fabrication and biological study of multilayer film coating with Zn on the surface of titanium substrateA bioactive multilayered structure of chitosan(Chi)/gelatin(Gel) pair containing Zn ion was constructed onto titanium substrates via a layer-by-layer(LBL) self-assembly technique. Firstly, Chi, Gel, and Zn2+were used to fabricate multilayer film coating. Furthermore, the successful fabrication of the multilayer film coating containing Zn2+ was demonstrated by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), X-ray photoelectron spectroscopy(XPS) and contact angle(CA) measurement, respectively. The Zn ion release was measured by inductively coupled plasma atomic emission spectrometry(ICP-AES). Osteoblasts were seeded onto native and treated titanium substrates to evaluate the cytocompatibility and measure cell viability, cell morphology and cell differentiation ability. The results indicated that cell viability, alkaline phosphates activity and cell adhesion were enhanced after surface modification. Two kinds of common bacteria, Staphylococcus aureus(S. aureus) and Escherichia coli(E. coli) were used to evaluate antibacterial property of native and treated titanium substrates. The multilayer film containing the proper amount of Zn2+ inhibited bacterial growth to some degree and showed antibacterial property.(2)The fabrication and biological study of the coating loaded with drug on the surface of titanium substrateIn this study, the coating loaded with antibacterial drug was fabricated onto the titanium substrate via LBL self-assembly combined with electrochemical anodization technique. Firstly, titanium dioxide nanotubes(TNT) arrays were constructed on the Ti substrate via an electrochemical anodization method. Then, TNT arrays were used as reservoirs for gentamicin. Chi and sodium alginate(SA) multilayer films were fabricated onto TNT for sealing antibacterial drug via LBL self-assembly. The successfully formation of multilayer films was demonstrated via SEM, and CA measurement. Cell viability, morphology and differentiation of osteoblasts onto native and treated titanium substrates were evaluated. The coating loaded with drug fabricated via LBL self-assembly combined with electrochemical anodization technique showed good biocompatibility. S. aureus and E. coli were seeded onto native and treated titanium substrates. Bacterial viability and morphology were measured. The results showed that the coating loaded with antibacterial drug inhibited bacterial growth and enhanced the antibacterial property of titanium substrates.In order to solve the currently existed poor osseo-integration and postoperative infection of titanium and its alloys, it is great significance to improve osteoblasts response and make them with antibacterial function via surface modification. This study presented here will provide novel strategies for surface modification of titanium-based implants and accelerate the application of them in tissue repair and regeneration.