Turn Hood into Good:\nRecycling Silicon from Mesoporous\nSilica Nanoparticles through Magnesium Modification to Lower Toxicity\nand Promote Tissue Regeneration

Mesoporous silica nanoparticles (MSNs) have gained wide\napplication\nas excellent carrier materials; however, their limited degradation\nin the biological system and potential chronic toxicity pose challenges\nto their clinical applications. Previous studies have focused on optimizing\nthe elimination performance of MSNs; interestingly, silicon has been\nwell-documented as an essential body component. Therefore, converting\nMSNs into a form readily utilizable by the organism is a way to turn\nwaste into a valuable resource. However, the recycling and utilization\nof MSNs are associated with significant hurdles. This study proposes\nan approach to impede the formation of siloxane, the crucial core\nin MSNs, by introducing a gradient concentration of Mg<sup>2+</sup>. The invasion of Mg<sup>2+</sup> significantly reduces the stability\nof Si–O–Si bonds by substituting silicon ions while\npreserving the functional three-dimensional structure. Recycling the\nincreased release of Mg and Si ions enhances cellular antioxidant\ncapacity, reduces oxidative stress reactions, improves mitochondrial\nfunction, and regulates macrophage inflammatory states. The proposed\napproach to converting MSN materials shows significant advantages\nfor tissue regeneration in the periodontal defect model. This study\nopens an insight for applying MSNs in clinical applications in regenerative\nmedicine.