3D Printed Titanium Alloy Scaffold Loaded With Silicon-based Biomaterials For Bone Repair

Titanium alloy has been widely used as a bone repair material in clinical applications.It has the advantages of high strength,good biocompatibility,stable physical and chemical properties,and good corrosion resistance.However,titanium alloy lacks biological activity,so it is necessary to improve its biological activity.In recent years,silicon-based bioactive materials showed outstanding performance,in order to make the combination of the high strength of titanium alloy and the good bioactivity performance of silicon-based biomaterials better together,making them form a new type of orthopaedic scaffolds with both high strength and high osteogenetic activity of titanium-silicon-based composite biological materials,this article has carried on the research content as follows:1.Previously,we studied the in vitro biological effects of 3D printed titanium alloy scaffolds with surface modification of bioactive glass?BG?and mesoporous bioactive glass?MBG?,which proved that the addition of this bioactive glass can effectively enhance the adhesion,proliferation and differentiation of human bone marrow stromal cells?h BMSCs?.Here,we further evaluate the therapeutic effect of this scaffold on rabbit bone defect repair in vivo.After 3,6,and 9 weeks after implanting the stent into the rabbit femoral defect,micro-computed tomography?micro-CT?imaging was performed,the mineral apposition rate?MAR?was measured using fluorescent dual-labeling,and histological analysis was performed on the undecalcified sections.Studies have confirmed that in the group of bioactive coatings,especially the mesoporous bioactive glass?MBG?group,the number of new bone and related bone morphological parameters increased significantly,and the adhesion and maturation of bone matrix were more obvious,and with bone growth,there is more angiogenesis.The results show that MBG can enhance the bone regeneration performance of titanium alloy scaffolds,including improving bone conduction and promoting vascularization in bone repair.2.A uniform and ordered Ti O₂ nanotube arrays were formed by two-step anodization on the surface of porous titanium alloy scaffold prepared by selective laser melting?SLM?.Further,a vacuum-assisted method is used to load the precursor solution of mesoporous bioactive glass?MBG?into the nanotubes,and the mesoporous bioactive glass?MBG?is loaded into the Ti O₂ nanotubes after solvent volatilization,self-assembly and heat treatment.Mechanical tests show that the mechanical strength of the 3D printed titanium alloy scaffold loaded with MBG is still around 50MPa,which meets the compressive strength requirements of human cancellous bone.At the same time,ion release experiments show that MBG in Ti O₂nanotubes can effectively achieve the long-time release of biologically active ions such as Ca and Si.In vitro cell experiments show that in the presence of nanotubes,h BMSCs grow more pseudopodia and have a better growth state.After nanotubes are loaded with mesoporous bioactive glass,it is more conducive to promoting cell proliferation,which means the scaffold loaded MBG has good cell compatibility and biological activity.3.In cooperation with other research institutions,bamboo-like titanium alloy scaffolds with high strength connected pores were designed and prepared by selective laser melting?SLM?.A vacuum assisted method is used to fill it with a suitable concentration of akermanite slurry,using freeze dryer technology to remove water,and then sinter and deposit the ceramics in the titanium alloy scaffold in an argon atmosphere.By adjusting the amount of ceramic content in the slurry,it is possible to load ceramic rods of different sizes in the titanium alloy support with the communicating pores.The results of the mechanical test show that the average compressive strength of the stent is 200 MPa,which meets the requirements for the compressive strength of human cortical bone.At the same time,an XRD test was performed on the surface of the heat-treated stent,and the results showed that electron-deficient titanium dioxide?Ti₃O₅?was formed on the surface of the titanium alloy scaffold.Therefore,the scaffold had a certain photothermal effect,may be further used for photothermal therapy.The above results show that by SLM technology,different types of 3D printing titanium alloy scaffolds can be personalized prepared,by adopting different compound methods,building bioactive glass coating on the titanium alloy scaffold's surface or loading high biological activity material akermanite in the scaffold,can form the different types of titanium alloy-silicon-based biological composite materials.Different compound types are expected to meet clinical needs for cancellous bone repair and in weight-bearing areas'cortical bone repair.