Work

Nano-MgO/PMMA bone cement with dual-phase anti-infection and immunomodulatory properties for infected bone regeneration

Year: 2026

Type: article

Abstract: Infectious bone defects pose a major clinical challenge due to persistent bacterial biofilms and dysregulated immune responses. To address these limitations, we developed an antibiotic-free bone cement by incorporating nano-magnesium oxide (Nano-MgO) into polymethylmethacrylate (PMMA), enabling simultaneous antibacterial action and immunomodulation. The Nano-MgO/PMMA bone cements demonstrated an optimal 10% increase in strength and sustained Mg 2+ release (highest 2.6 mg/L with 25% MgO addition after 14 days of immersion in Hank's solution). A biphasic regulatory mechanism was identified. In the early phase, Nano-MgO promoted intracellular reactive oxygen species (ROS) production in macrophages, contributing to membrane-disruptive antibacterial activity and supporting M1-associated immune responses involved in biofilm clearance. In the later phase, the gradual release of Mg 2+ facilitated macrophage M2 polarization, promoting inflammation resolution and tissue repair. These effects were validated through in vitro antibacterial and immunomodulatory assays, and further confirmed in vivo assessments using subcutaneous infection and rat femoral condyle defect models. Single-cell RNA sequencing of the peri-implant immune microenvironment revealed a time-dependent shift in inflammatory pathways, underscoring the material's dynamic immunoregulatory capacity. Collectively, Nano-MgO/PMMA represents a promising antibiotic-free strategy for managing infectious bone defects by integrating effective infection control with immune-guided tissue regeneration. • Nano-MgO/PMMA bone cement enables antibiotic-free antibacterial action and immunomodulation for infected bone repair. • Nano-MgO disrupts bacterial membranes via ROS and promotes M1.→M2 macrophage shift for infection control and tissue repair. • Dual-phase Mg 2+ release regulates immune response: early M1 (anti-biofilm) and late M2 (pro-repair), validated in vivo.

Source: Smart Materials in Manufacturing