Magnesium-based biomaterials as emerging agents for bone repair and regeneration: from mechanism to application

Magnesium (Mg) is the fourth most abundant element in the human body and is important in terms of specific osteogenesis functions. Here, we provide a comprehensive review of the use of magnesium-based biomaterials (MBs) in bone reconstruction. We review the history of MBs and their excellent biocompatibility, biodegradability and osteopromotive properties, highlighting them as candidates for a new generation of biodegradable orthopedic implants. In particular, the results reported in the field-specific literature (280 articles) in recent decades are dissected with respect to the extensive variety of MBs for orthopedic applications, including Mg/Mg alloys, bioglasses, bioceramics, and polymer materials. We also summarize the osteogenic mechanism of MBs, including a detailed section on the physiological process, namely, the enhanced osteogenesis, promotion of osteoblast adhesion and motility, immunomodulation, and enhanced angiogenesis. Moreover, the merits and limitations of current bone grafts and substitutes are compared. The objective of this review is to reveal the strong potential of MBs for their use as agents in bone repair and regeneration and to highlight issues that impede their clinical translation. Finally, the development and challenges of MBs for transplanted orthopedic materials are discussed.