Bismuth Subsalicylate Nanoparticles Synthesized by Laser Ablation Against Oral Bacteria

Objectives: The use of nanoparticles as antimicrobial agents is one of the most promising strategies to overcome infections and bacterial drug resistance. Bismuth subsalicylate (BSS) has been reported to be effective in the inhibition of Helicobacter pylori. However, there is not information regarding the antibacterial effect of BSS nanoparticles. The aim of the present study was to evaluate the antibacterial effectiveness of bismuth subsalicylate nanoparticles (BSS-NPs) against oral bacterial strains.
Methods: BSS-NPs were synthesized by the laser ablation technique. The characterization of the nanoparticles was performed by transmission electron microscopy (TEM), UV-Vis spectrum and X-ray Diffraction (XRD). Five different concentrations (0.74, 1.53, 3.07, 6.14 and 8.64 µg/mL) of BSS-NPs were tested against pure cultures of Actinomyces israelii, Aggregatibacter actinomycetemcomitans serotype b, Capnocytophaga gingivalis, Eikenella corrodens, Fusobacterium nucleatum subsp. nucleatum, Parvimonas micra, Porphyromonas gingivalis, Prevotella intermedia, Streptococcus mutans and Streptococcus sanguinis.
Results: TEM analysis showed a semi-circular particle morphology and an average particle size of 22 nm. The UV-Vis spectrum indicated the presence of functional groups of BSS in the nanoparticles and the analysis with X-ray diffraction indicated that the BSS-NPs have crystallographic structure corresponding to BSS. The antibacterial assays shown that the BSS-NPs had an inhibitory effect with in all the concentrations tested. Minimum Inhibitory Concentration of 90 (MIC90) was reach using 0.76 ug/mL against C. gingivalis and P. micra; 1.53 µg/mL against A. israelli, P. gingivalis and S. sanguinis; 3.07 µg/mL against E. corrodens, F. nucleatum and P. intermedia, 6.14 µg/mL against S. mutans and 8.64 µg/mL against A. actinomycetemcomitans.
Conclusions: Bismuth subsalicylate nanoparticles obtained by laser ablation were effective to inhibit the growth of the oral bacterial strains tested.