Surface Treatment Of Magnesium Alloy With Hydrotalcite Coating And Study On The Antibacterial Activity In Vitro

Owing to the proper biomechanics,biocompatibility and properties absorbable,magnesium alloy has broden a new aera on the research of orthopedic implant.However,However,fast corrosion rate can result in undesired loss of mechanical properties prior to predesigned service duration.Furthermore,during implant operation process,bacterials adhered to the surface of implants and secreted biofilm which hindered the ossteogration.In this study,Mg-Al hydrotalcite coating was fabricated on Mg-3Zn-0.8Zr-0.3Sr alloy using hydrothermal reaction.Based on the above research,Ag element was introduced onto LDH film.We get such conclusion:（1）By means of the orthogonal test and max-min difference,hydrotalcite coating was grown in-situ using simple hydrothermal method and the best condition was as follow:temperature was 130°C,duration was 8 h,pH was adjusted to 13 and the content of sodium aluminate was added to 10 mM.With this reaction condition,the LDH coating had the lowestcorrosion,bonding strength and surface quality.（2）Using simple factor analysis,we studied the formation mechanism of hydrotalcite conversion film in terms of reaction parameters（pH,temperature,concentration and duration）.The possible the process of coating growth was as follow:First Mg（OH）₂was formed and some octahedral coordinated-site was replaced by Al³⁺,immediatelyMg（OH）₂ was dissolution and diffusion,followed by Al³⁺loss of the LDH precursor.（3）AgNO₃ was introduced into reaction system and nanoAg⁰ was detected on LDH coating via simple one step process.The cell compatibility test and antibacterial assay showed that 30μMAgNO₃ group had excellent ossteoblast vitality and proliferation,likewise,proper antibacterial ability.