Controlled magnesium ion delivery system for in situ bone tissue engineering

Magnesium cation (Mg2+) has been an emerging therapeutic agent for inducing vascularized bone regeneration. However, the therapeutic effects of current magnesium (Mg)-containing biomaterials are controversial due to the concentration-and stage-dependent behavior of Mg2+. Here, we first provide an overview of biochemical mechanism of Mg2+ in various concentrations and suggest that 2-10 mM Mg2+ in vitro may be optimized. This review systematically summarizes and discusses several types of controlled Mg2+ delivery systems based on polymer-Mg composite scaffolds and Mg-containing hydrogels, as well as their design philosophy and several parameters that regulate Mg2+ release. Given that the continuous supply of Mg2+ may prevent biomineral deposition in the later stage of bone regeneration and maturation, we highlight the controlled delivery of Mg2+ based dual-or multi-ions system, especially for the hierarchical therapeutic ion release system, which shows enhanced biomineralization. Finally, the remaining challenges and perspectives of Mg-containing biomaterials for future in situ bone tissue engineering are discussed as well.

Automated summary

This article provides an overview of the biochemical mechanism of magnesium cation in inducing vascularized bone regeneration, and suggests optimizing the concentration of magnesium ions. It also summarizes various controlled magnesium delivery systems based on polymer-Mg composite scaffolds and Mg-containing hydrogels, discussing their design philosophy and parameters that regulate magnesium release. The importance of controlled delivery of magnesium ions in a dual-or multi-ions system, as well as the challenges and perspectives of magnesium-containing biomaterials for in situ bone tissue engineering, are highlighted.