Metal-Organic Framework-Based Surface Engineering of Biomedical Magnesium Alloys: Types, Electrochemical Behaviour, Corrosion Protection Mechanisms, Biomedical Applications, and Future Challenges

Abstract

The biodegradable magnesium (Mg) alloys are found to have some of the most desirable mechanical properties, biodegradability and biological functions, which are beneficial for temporary orthopedic and cardiovascular implants. However, their extremely rapid corrosion rates in physiological environments, hydrogen evolution, localized alkalization, and loss of mechanical integrity early on are great challenges for their clinical translation. Metal-organic frameworks (MOFs) have been the focus of much research in recent years as multifunctional platforms for surface modification to overcome these limitations. The MOF materials offer unique opportunities to enhance their corrosion resistance, bioactivity, antibacterial property, and therapeutic function, because of their highly porous nature, tunable chemical compositions, controlled ion release, and drug loading abilities. This systematic review provides a detailed review of coating of magnesium alloys using MOFs for biomedical applications with the emphasis on MOF of elements such as Zn, Fe, Co, Cu, Zr, Ti, and Ni. In the review, 180 peerreviewed publications from 2016 to 2026 were analysed and discussed, which focused on the structural characteristics, preparation methods, electrochemical properties, tribological properties and biomedical applications of MOF-MgAlloys. The Zn-based MOFs are particularly noted for their outstanding corrosion protection properties, osteo-inductive properties, and anti-bacterial activities. The electrochemical mechanisms of corrosion protection are analyzed and discussed, such as: physical barrier effect, pore blocking, controlled ion release, self-healing and hybrid plasma electrolytic oxidation (PEO)-MOF protection. In addition, the review provides a summary of the recent advances of orthopedic implants, cardiovascular stents, drug delivery systems, as well as antibacterial implants and tissue engineering scaffolds. Although tremendous strides have been made, problems of coating stability over time, lack of delamination, defect formation, cytotoxicity, manufacturing scalability, and insufficient clinical evidence remain. Design of multifunctional MOFs, standardization of electrochemical testing methods, long-term in vivo studies, tribocorrosion testing and artificial intelligence design of MOFs are future research opportunities to be explored. In general, MOF functionalized magnesium alloys could be considered as one of the most rapidly developing and promising classes of next generation biodegradable biomaterials for advanced biomedical applications.