Advances in layer-by-layer self-assembled coatings upon biodegradable magnesium alloys

Abstract

Magnesium (Mg) and its alloys are considered as ideal biodegradable materials due to their excellent mechanical properties and biocompatibility. In order to improve the surface properties to allow better adaptation to the surrounding tissue of the body, surface modification has played a significant role in satisfying multiple clinical requirements such as corrosion resistance, biocompatibility, and antibacterial ability. Here, layer-by-layer (LbL) self-assembly, which can be applied for biodegradable Mg alloys due to its extensive choice of usable units, holds great promise among all the surface techniques. In this review, the mechanisms of the driving force (i.e., electrostatic interaction, hydrogen bonding, charge transfer interaction and covalent bonding), cutting-edge advances in preparation methods (e.g., dipping, spraying, and spinning) and the functional properties (corrosion resistance, antibacterial activity, and biocompatibility) that could be achieved by the LbL coatings are summarized. A reasonable trend of the potential development of LbL for bio-Mg alloys is also proposed at the end of this article.