Abstract
Mg alloys are promising biodegradable orthopedic implants in the future. However, poor corrosion resistance and biocompatibility limit their wide applications. In this study, a pure Mg-Al layered double hydroxide (Mg-Al LDH) film on AZ31 was prepared through combining hydrofluoric acid pretreatment and hydrothermal treatment. Electrochemical analysis and the immersion test suggested that the as-prepared Mg-Al LDH-coated sample exhibited significantly enhanced corrosion resistance. The in vitro cell culture revealed that the Mg-Al LDH film was favorable for the alkaline phosphatase activity, collagen secretion, and osteogenesis-related gene expression of MC3T3-E1. Furthermore, the LDH-coated sample was beneficial for the migration, vascular endothelial growth factor secretion, and angiogenesis-related gene expression of human umbilical vein endothelial cells. The subcutaneous implantation test demonstrated that the Mg-Al LDH film could protect the substrate from corrosion and induce milder inflammation. The femur implantation demonstrated that the Mg-Al LDH sample showed better bone regeneration and osseointegration than bare AZ31. In summary, the as-prepared pure Mg-Al LDH film is able to enhance the in vitro and in vivo performances of AZ31, indicating a promising application in the orthopedic field.