Surface design of biodegradable magnesium alloys — A review

Biodegradability is a big advantage of magnesium-based materials in biomedical applications such as bone fixation, cardiovascular stents, and even stomach trauma repair. Different from other metals such as stainless steels and Ti alloys, the interface between the Mg-based implants and biological environment is dynamic. In order to improve the surface properties to allow better and more expeditious adaptation to the physiological surroundings, it is imperative to design and construct a surface to satisfy multiple clinical requirements such as mechanical strength, biocompatibility, and degradation rate. This paper reviews recent work pertaining to surface modification of Mg-based biomaterials with emphasis on surface coatings and ion implantation. The biodegradation behavior and related mechanism in the physiological environment after surface modification are also described. Surface modification is a promising means to elevate the performance of Mg-based biomaterials and expected to be extensively applied to surface design of biomaterials.