Magnesium Oxide

Magnesium oxide (MgO) exerts its antibacterial effects through a synergistic combination of physical and chemical mechanisms. The primary mechanism involves the generation of reactive oxygen species (ROS), including hydroxyl radicals, superoxide anions, and singlet oxygen, which exert strong oxidative effects that disrupt bacterial cell membranes and react with intracellular biomacromolecules. MgO nanoparticles also induce direct physical damage to bacterial cells through electrostatic interactions between the positively charged MgO surface and negatively charged bacterial membranes, leading to membrane disruption and leakage of intracellular contents.
Additionally, the release of Mg²⁺ ions and the alkaline environment created by MgO hydration contribute to bacterial growth inhibition. Unlike conventional antibiotics, MgO does not induce bacterial resistance and exhibits excellent biocompatibility, low toxicity, and broad-spectrum antibacterial activity. These properties make MgO a promising candidate for reducing orthopaedic implant-related infections (IRIs).

Fig. 1 Antibacterial properties of calcium sulfate-MgO composites implanted in rat muscles. (Wang Y.; et al. 2025)

MgO@SiO₂ core-shell nanocapsules were developed as a ROS-responsive controlled-release nanosystem for osteoarthritis treatment. The silica coating extended MgO nanoparticle release duration from 12 hours to 3 to 5 days both in vitro and in vivo. At low concentrations (5 mM), the nanocapsules suppressed intracellular reactive oxygen species generation in chondrocytes and reduced expression of pro-inflammatory factors including IL-6, MMP-13, and COX-2, whereas higher concentrations (>10 mM) increased ROS production. In a rat osteoarthritis model, intra-articular injection of 5 mM MgO@SiO₂ significantly alleviated cartilage degeneration.

Fig. 2 Preparation of MgO@SiO₂ core-shell nanocapsules. (Zheng Y.; et al. 2025)