Mucus-Permeable Sonodynamic Therapy Mediated Amphotericin B-Loaded PEGylated PLGA Nanoparticles Enable Eradication of Biofilm.

Background: () forms pathogenic biofilms, and the dense mucus layer secreted by the epithelium is a major barrier to the traditional antibiotic treatment of mucosa-associated infections. Herein, we report a novel anti-biofilm strategy of mucus-permeable sonodynamic therapy (mp-SDT) based on ultrasound (US)-mediated amphotericin B-loaded PEGylated PLGA nanoparticles (AmB-NPs) to overcome mucus barrier and enable the eradication of biofilm.

Methods: AmB-NPs were fabricated using ultrasonic double emulsion method, and their physicochemical and sonodynamic properties were determined. The mucus and biofilm permeability of US-mediated AmB-NPs were further investigated. Moreover, the anti-biofilm effect of US-mediated AmB-NPs treatment was thoroughly evaluated on mucus barrier abiotic biofilm, epithelium-associated biotic biofilm, and induced rabbit vaginal biofilms model. In addition, the ultrastructure and secreted cytokines of epithelial cells and the polarization of macrophages were analyzed to investigate the regulation of local cellular immune function by US-mediated AmB-NPs treatment.

Results: Polymeric AmB-NPs display excellent sonodynamic performance with massive singlet oxygen (O) generation. US-mediated AmB-NPs could rapidly transport through mucus and promote permeability in biofilms, which exhibited excellent eradicating ability to biofilms. Furthermore, in the vaginal epithelial cells (VECs)-associated biofilm model, the mp-SDT scheme showed the strongest biofilm eradication effect, with up to 98% biofilm re-formation inhibition rate, improved the ultrastructural damage, promoted local immune defense enhancement of VECs, and regulated the polarization of macrophages to the M1 phenotype to enhance macrophage-associated antifungal immune responses. In addition, mp-SDT treatment exhibited excellent therapeutic efficacy against induced rabbit vaginitis, promoted the recovery of mucosal epithelial ultrastructure, and contributed to the reshaping of a healthier vaginal microbiome.

Conclusion: The synergistic anti-biofilm strategies of mp-SDT effectively eradicated biofilm and simultaneously regulated local antifungal immunity enhancement, which may provide a new approach to treat refractory drug-resistant biofilm-associated mucosal candidiasis.