Effect Of Oxygen-Supplying Nanoparticles Mediated Photodynamic Therapy On Periodontitis

This study aimed to develop oxygen-generating methylene blue-loaded PLGA nanoparticles (MB@MnO₂-PLGA NPs) to overcome hypoxia limitations and photosensitizer instability in antimicrobial photodynamic therapy (aPDT) for periodontal biofilms. MB@MnO₂-PLGA NPs were synthesized via emulsion-solvent evaporation and characterized by UV-Vis/FTIR spectroscopy, SEM/TEM, and zeta potential. Antimicrobial efficacy against Porphyromonas gingivalis and Fusobacterium nucleatum (planktonic/dual-species biofilms) was assessed via colony counting after 660 nm irradiation (120 mW/cm², 1ཞ5 min). Cytocompatibility was evaluated using CCK-8 assays on periodontal ligament cells. 1) Characterization confirmed spherical NPs (300 nm) with core-shell structures, MB absorption at 664 nm, and colloidal stability (PDI=0.325; Zeta=-7.70 mV). 2) In antimicrobial assays, compared with the control, MMP-aPDT (66 μg/mL MB-equivalent) achieved bactericidal rates of 90.05% and 96.26% against P. gingivalis and F. nucleatum, respectively (P < 0.005), while maintaining >80% cell viability. Free MB exhibited cytotoxicity above 8.25 μg/mL (p<0.05). MTT analysis demonstrated significant suppression of dual-species biofilm metabolic activity post-aPDT (p<0.05). The oxygen-self-supplying MB@MnO₂-PLGA NPs synergistically enhance aPDT efficacy by resolving hypoxia and improving PS stability, offering a promising strategy for clinical management of refractory periodontitis.