Construction And Properties Of Bioactive Layer On The Surface Of Titanium Alloy Scaffolds

In this paper,we focused on the lacking of biological activity of the metal bone tissue engineering materials in the repair of large bone defects,fully consider the biological significance of chemical composition and morphology on the surface of material,mainly on cell adhesion and differentiation and new bone formation during the repair process,by surface modification of porous titanium alloy stents made of selective laser melting method with structural and mechanical properties highly controllable to achieve high surface osteogenic and angiogenic activity,and to achieve ideal bone internal growth.The main research contents are as follows:?1?Mesoporous bioactive glass?MBG?is a kind of material which possesses large specific surface area and pore volume,and its ordered mesoporous structure is favorable for the rapid release of Ca,Si and P ions.Therefore,MBG material cannot only promote bone conduction,but also showed the ability to promoting bone growth.Based on the excellent biological activity of MBG,this work constructed MBG coating on porous Ti-6Al-4V scaffold by spin-coating method.The physical properties of the coating were characterized.At the same time,the physicochemical properties,in vitro cell biological activities and in vivo osteogenic properties of the pure Ti-6Al-4V scaffolds,the traditional bioactive glass?BG?modified Ti-6Al-4V scaffolds and the MBG-modified Ti-6Al-4V groups were characterized.?2?In addition,based on above work,we further prepared ordered nanotube structure by anodic oxidation method on the surface of porous Ti-6Al-4V scaffolds,and then loaded MBG in the nanotube to reach two purposes:1)To achieve the biological synergy of titanium dioxide nanotubes and the release of mesoporous glass ions;2)Regulate ion release of mesoporous glass through the support of nanotubes.Now we have confirmed that by spin coating,a uniform MBG coating can be formed on the surface of the Ti-6Al-4V scaffold,and a good bonding interface between the coating matrix was created,and also the coating retains its original chemical composition and mesoporous structure.At the same time,the MBG-Ti-6Al-4V scaffold significantly enhanced the proliferation and osteogenic differentiation ability of human bone marrow-derived mesenchymal stem cells?hBMSC?compared with pure Ti-6Al-4V scaffold and the traditional bioactive glass?BG?modified Ti-6Al-4V scaffold.Also we found that in the hydrofluoric acid inorganic electrolyte system,TiO₂ nanotubes with a diameter of 60 nm can be prepared on the Ti-6Al-4V three-dimensional scaffold and we tried to load MBG solution into nanotube by vacuuming.By in vitro cell-based assays showed that MBG-loaded nanotubes titanium scaffolds revealed better proliferation and adhesion abilities of human bone marrow mesenchymal stem cells?hBMSCs?,as well as a higher osteogenic differentiation of alkaline phosphatase ALP activity.The above results indicate that it is possible to provide a new method for the construction of titanium scaffolds with excellent bone-forming ability through chemical composition and morphology modification of titanium alloy scaffold surface.It is expected to be used in large segmental bone repair and regeneration.At the same time,the loading of the MBG in the nanotubes and the synergy effect between two factors worth further exploration.