Biodegradable metals have garnered considerable interest owing to their capacity for self-degradation following the repair of damaged tissues. This review commences with their historical development and clarifies the essential prerequisites for their successful clinical translation. Subsequently, a detailed review of magnesium-based materials is presented from five critical areas of alloying, fabrication techniques, purification, surface modification, and structural design, systematically addressing their progress in biodegradation rate retardation, mechanical reinforcement, and biocompatibility enhancement. Furthermore, recent breakthroughs in vivo animal experiments and clinical translation of magnesium alloys are summarized. Finally, this review concludes with a critical assessment of the achievements and challenges encountered in the clinical application of these materials, and proposes practical strategies to address current limitations and guide future research perspectives.

Biodegradable metals such as magnesium (Mg) and its alloys have attracted extensive attention in biomedical research due to their excellent mechanical properties and biodegradability. However, traditional casting, extrusion, and commercial processing have limitations in manufacturing components with a complex shape/structure, and these processes may produce defects such as cavities and gas pores which can degrade the properties and usefulness of the products. Compared to conventional techniques, additive manufacturing (AM) can be used to precisely control the geometry of workpieces made of different Mg-based materials with multiple geometric scales and produce desirable medical products for orthopedics, dentistry, and other fields. However, a detailed and thorough understanding of the raw materials, manufacturing processes, properties, and applications is required to foster the production of commercial Mg-based biomedical components by AM. This review summarizes recent advances and important issues pertaining to AM of Mg-based biomedical products and discusses future development and application trends.

Although magnesium (Mg) and its alloys are proposed as the next generation orthopedics transplanted materials, their clinical applications are limited by the fast degradation. To reduce the degradation rate, a strong adhesion poly-dopamine (PDA) layer was introduced as an intermediate layer for the subsequent alginate (ALG) spin-coating on high-purity Mg. The surface morphology and chemical composition were detected by scanning electron microscope, energy disperse spectroscopy, and Fourier transform infrared spectroscopy. The corrosion resistances of all samples were evaluated by electrochemical and 10-day immersion tests in Hanks’ balanced salt solution. Our results suggest that the thickness of the fabricated PDA/ALG composite coating is 8.58 ± 0.65 µm, and the intermediate PDA layer evidently enhances the adhesion between the substrate and ALG coating. The corrosion current density of Mg coated with the PDA/ALG composite coating decreases more than 10 times compared to that of the Mg substrate, and the charge transfer resistance is 12 times bigger than that of the bare Mg, which indicates the improved corrosion resistance. Moreover, the mechanism of corrosion protection of the composite coating is also discussed.