Research Progress on Surface Modification of Magnesium-based Bone Implants
Due to the unique degradability,excellent biocompatibility and similar density to bone,magnesium and its alloys have become the choice of biodegradable implants for orthopedic clinical applications.In recent years,surface modification technology has been fully developed to endow magnesium-based bone implants with corrosion resistance and biological functions,which is conducive to better responding to the complex clinical application environment.The work aims to review the research progress of surface modification of magnesium-based bone implants in recent years,and briefly discuss the problems and future development directions of various surface modification methods.Firstly,the background information on the clinical demand for bone implants,the performance advantages and limitations of magnesium-based implants,and the in vivo application environment were introduced.On this basis,according to the functional classification,the research progress of surface modification technology of magnesium-based bone implants was mainly described.The preparation methods,functional characteristics and mechanism of action were described respectively,and the existing problems are pointed out.Finally,the future perspectives of surface modification of magnesium-based bone implants are discussed rationally.According to their different functions,the surface modification of magnesium-based bone implants can be divided into corrosion resistant coatings,bone healing coatings,antibacterial coatings,self-healing coatings,and biological immune coatings.Corrosion resistant coatings,including micro-arc oxidation(MAO)coating,sol-gel coating and hydrothermal coating,can provide physical shielding for the substrate to resist the erosion of inorganic ions and organic substances in the bone environment,thereby effectively controlling the degradation rate of the substrate.The bone healing coatings mainly use bone healing drugs and bone-like bioactive substances to promote osteogenesis and inhibit osteoclast activity.The antibacterial coatings mainly exert antibacterial properties through metal ions(such as Ag,Ga,Zn,Cu,etc.)and antibacterial drugs(gentamicin,ciprofloxacin,vancomycin,etc.).Self-healing coatings are classified into two categories,autonomous and triggered,based on whether they achieve repair of coating damage through external intervention.The biological immune coatings mainly realize immune regulation by altering the macroscopic morphology and adding alloy elements and immunologically active factors.Existing studies have shown that the surface modification of magnesium-based bone implants can realize the introduction of biological functions on the basis of improving the corrosion resistance.However,for the complex service environment,there are few studies on the sequential function of constructing multi-stage composite coatings to achieve antibacterial and anti-infection properties in the initial stage and promote bone growth in the middle and late stages.In addition,the differences in specific implant sites and functional requirements faced by implants have not been studied in depth.In the future,the surface modification of magnesium-based bone implants is expected to achieve breakthroughs in the fields of spontaneous sequential function,customized design of service environment and refractory bone repair.
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维普
