The wide application of magnesium alloys as biodegradable implant materials is limited because of their fast degradation rate. Hydroxyapatite (HA) coating can reduce the degradation rate of Mg alloys and improve the biological activity of Mg alloys, and has the ability of bone induction and bone conduction. The preparation of HA coating on the surface of degradable Mg alloys can improve the existing problems, to a certain extent. This paper reviewed different preparation methods of HA coatings on biodegradable Mg alloys, and their effects on magnesium alloys’ degradation, biocompatibility, and osteogenic properties. However, no coating prepared can meet the above requirements. There was a lack of systematic research on the degradation of coating samples in vivo, and the osteogenic performance. Therefore, future research can focus on combining existing coating preparation technology and complementary advantages to develop new coating preparation techniques, to obtain more balanced coatings. Second, further study on the metabolic mechanism of HA-coated Mg alloys in vivo can help to predict its degradation behavior, and finally achieve controllable degradation, and further promote the study of the osteogenic effect of HA-coated Mg alloys in vivo.

The barrier membrane plays an extremely critical role in guided bone regeneration (GBR), which determines the success or failure of GBR technology. In order to obtain barrier membranes with high mechanical strength and degradability, some researchers have focused on degradable magnesium alloys. However, the degradation rate of pure Mg-based materials in body fluids is rather fast, thus posing an urgent problem to be solved in oral clinics. In this study, a novel micro-arc oxidation (MAO) surface-treated pure Mg membrane was prepared. Electrochemical tests, immersion experiments and in vivo experiments were carried out to investigate its potential use as a barrier membrane. The experimental results showed that the corrosion resistance of a pure Mg membrane treated by MAO is better than that of the uncoated pure Mg. The results of cell experiments showed no obvious cytotoxicity, which suggests the enhanced differentiation of osteoblasts. At the same time, the MAO-Mg membrane showed better biological activity than the pure Ti membrane in the early stage of implantation, exhibiting relatively good bone regeneration ability. Consequently, the MAO membrane has been proven to possess good application prospects for guided bone regeneration.

Mg-Sr alloy is considered as a promising biodegradable bone repair material. However, its poor corrosion resistance limits its clinical application. In this study, the corrosion rate of Mg-Sr alloy was greatly improved through the heat treatment. Both in vitro and in vivo corrosion tests (immersion and electrochemical test) showed that corrosion resistance of Mg-Sr alloy was enhanced. In the animal test (New Zealand rabbit), both micro-CT analysis and Van Gieson staining demonstrated that the treated Mg-Sr alloy implant exhibited better osteogenesis and osteointegration ability, which accelerate the healing of bone defect. The results indicate that the treated Mg-Sr alloy has great possibility and potential for application as a new bone repair material.

In recent years, biodegradable magnesium (Mg) alloys have attracted the attention of many researchers due to their mechanical properties, excellent biocompatibility and unique biodegradability. Many Mg alloy implants have been successfully applied in clinical medicine, and they are considered to be promising biological materials. In this article, we review the latest research progress in biodegradable Mg alloys, including research on high-performance Mg alloys, bioactive coatings and actual or potential clinical applications of Mg alloys. Finally, we review the research and development direction of biodegradable Mg alloys. This article has a guiding significance for future development and application of high-performance biodegradable Mg alloys, promoting the future advancement of the magnesium alloy research field, especially in biomedicine.