MgO Nanomaterials Exert Antibacterial Activity Through Combined Mechanical Damage and ROS‐Mediated Oxidation

ABSTRACT MgO nanomaterials have emerged as promising inorganic antibacterial agents due to their high efficiency, broad‐spectrum activity, and biosafety. In this study, a series of MgO nanomaterials was synthesized via the solution combustion method by adjusting the molar ratio of magnesium nitrate (oxidant) and urea (fuel). Notably, the as‐synthesized MgO nanomaterials exhibited excellent antibacterial activity without requiring high‐temperature calcination. When the molar ratio of magnesium nitrate to urea was 1:5, the resulting MgO nanomaterial achieved >99% antibacterial efficacy against E. coli and S. aureus at a concentration of 500 ppm. To elucidate the underlying antibacterial mechanism, dialysis tube experiments and radical scavenger assays were conducted. The results revealed that the primary antibacterial action involved electrostatic adsorption of MgO nanomaterials onto bacterial cell walls, leading to mechanical damage and subsequent cell death. Furthermore, scavenger experiments confirmed that MgO nanomaterials induced the generation of reactive oxygen species (ROS) during the antibacterial process, which contributed to oxidative damage to bacterial cell membranes and intracellular biomacromolecules, thereby enhancing the overall antibacterial effect. The synergistic interplay of mechanical damage and ROS‐mediated oxidative stress provides a mechanistic basis for the potent antibacterial performance of MgO nanomaterials, offering valuable insights for the design of advanced inorganic antibacterial agents.