Application Of Personalized And Surface Functional Metal Materials On Bone Repair

Objective Every year the cost of orthopedic and dental implants is more than 20 billion yuan in China,but current standard implants cannot reconstruction and repair complex hard tissue defects or diseases accurately and effectively,and we need to develop personalized implants.Traditional implant materials,such as stainless steel and titanium alloy,are lack of bioactivity,osteoinductivity and osteoconductivity,and their geometric shape and mechanical properties cannot match with the defects,which could not achieve bone regeneration effectively after implanting in vivo.Therefore,if implant have both personalized morphological structure and biological function,the therapeutic effect of bone repair can be greatly improved.Content and Methods In this paper,according to the needs of clinical bone repair,we hope the implant manufactured by 3D printing technology and surface functionalization modification technology can satisfy the personalized needs of implant internal structure,mechanical properties,especially biological function in different patient and diseases.The purpose of current study is to improve the therapeutic effect of bone repair,which was divided into two mainly parts: Part one: The metal 3D printing technology is used to manufacture porous Ti6Al4 V scaffold with personalized space structure.The effect of pore size on the mechanical and biological properties of porous scaffold was investigated.Finally,the vacuum evaporation method was used to prepare biodegradable magnesium coating on the porous Ti6Al4 V scaffold and degradation pattern and osteogenetic activity of the magnesium coating was studied.Part two: The zoledronic acid(ZA)/CaP composite functional coating was prepared on the surface of magnesium alloys.This Mg/ZA/CaP composite implant was designed to combine the desirable properties of Mg and ZA for augmenting osteoporotic fracture healing via simultaneous regulation of bone formation and resorption.The drug release profile,biological effects,degradation behavior,fracture union and mechanism were explored.Results Porous Ti6Al4 V scaffolds with three pore sizes(300~400,400~500,and 500~700?m)were manufactured by metal 3D printing technology.The results of mechanical and biological evaluations indicated that the porous scaffold with pore size of 300~400?m have best mechanical and biological properties,which could obtain satisfactory bone osseointegration in goat segmental metatarsus defect model through promoting cell adhesion and osteogenesis.In vitro and in vivo results demonstrated that the osteogenesis activity was further improved after magnesium surface modification.In vitro and in vivo experiments results of the Mg/ZA/CaP implant showing a controllable,uniform degradation pattern,illustrating a controlled and sustained drug-release profile.The degradation products of Mg/ZA/CaP implant could enhance osteogenesis ability of OVX rBMSCs and inhibit murine osteoclastogenesis in vitro.Furthermore,the Mg/ZA/CaP intramedullary nails could promote bone callus mechanical property and bone union quality through improve endochondral bone formation and suppress excessive remodeling due to hyperfunctioning of osteoclasts.The slow and uniform degradation of the implant ensures a steady decrease in bending force,which meets clinical requirements.Conclusions In summary,based on metal 3D printing technology and suface functionalization modification,porous Ti6Al4 V scaffold with magnesium coating and Mg/ZA/CaP composite implant were manufactured for complicated bone defects or osteoporotic fracture respectively,which provided a favourable insight and approach for the theoretical research and clinical treatment of bone repair.