Nanoparticles having amphiphilic silane containing Chlorin e6 with strong anti-biofilm activity against periodontitis-related pathogens.

OBJECTIVES

The objectives of this study were to: (1) develop the multifunctional nanoparticles containing Chlorin e6 (Ce6), Coumarin 6 (C6) and FeO nanoparticles (NPs); and (2) investigate the inhibitory effects of the nanoparticles via antibacterial photodynamic therapy (aPDT) against three species of periodontitis-related pathogens for the first time.

MATERIALS AND METHODS

Ce6 and C6 were co-loaded into the FeO-silane core-shell structure to form multifunctional nanoparticles (denoted "FeO-silane@Ce6/C6 MNPs"). The physical and chemical properties of nanoparticles were characterized. Biofilm properties of Streptococcus sanguinis, Porphyromonas gingivalis and Fusobacterium nucleatum were tested. Colony-forming units (CFU), live/dead assay, and metabolic activity of biofilms were determined to evaluate the aPDT function mediated by the FeO-silane@Ce6/C6 MNPs. Fluorescence imaging and the targeted antibacterial effects were also investigated.

RESULTS

FeO-silane@Ce6/C6 MNPs showed superparamagnetic properties, chemical stability and water-solubility, with no cytotoxicity. FeO NPs did not compromise the emission peaks of C6 and Ce6. The FeO-silane@Ce6/C6-mediated aPDT had much greater reduction in biofilms than the control groups (p < 0.05). Biofilm CFU was reduced by about 4-5 orders of magnitude via FeO-silane@Ce6/C6-mediated aPDT. The co-loading of Ce6 and C6 enabled the real-time aPDT monitoring by ratio emissions with the same wavelength. FeO with magnetic field enabled the targeting of infection sites by killing bacteria via magnetic field.

CONCLUSION

The multifunctional nanoparticles exerted strong anti-biofilm activity against periodontitis-related pathogens, with excellent biocompatibility, real-time monitoring, and magnetically-targeting capacities. The multifunctional nanoparticles have great potential in antibacterial applications to inhibit the occurrence and progression of periodontitis.