Potential of laser-produced gold and silver nanoparticles against cariogenic biofilm

Objectives: Dental caries is costly and persistent global health issue, requiring better dental care products for its prevention. This study examined antibiofilm effectiveness of pulsed laser ablation- synthesized gold nanoparticles (Laser_AuNPs) and silver nanoparticles (laser_AgNPs) against four Streptococcus species (S. mutans, S. mitis, S. sanguinis, and S. gordonii), essential for cariogenic biofilm development. Methods: Nanoparticles were characterized for size using transmission electron microscopy. Ex vivo evaluation of the nanoparticles antibiofilm activity was performed against a four-species biofilm on enamel discs by quantifying CFU. Scanning electron microscopy was used to visualize the reduction in biofilm mass on enamel discs. Results: TEM showed nanoparticle sizes were 5.89 ± 0.25m and 7.00 ± 0.07 nm for Laser_AgNPs and laser_AuNPs, respectively. Reductive potential of laser_AuNPs against multispecies biofilm settled on enamel discs was comparable (ΔlogCFU 2.07±0.61) to the one of the mouthwash containing chlorhexidine (ΔlogCFU 2.58±1.13). On the other hand laser_AgNPs proved more efficient biofilm reduction (ΔlogCFU 5.23±0.72). SEM results confirmed that treatment with laser_AuNPs resulted in the biofilm mass decrease, and that the reduction was more pronounced after treatment with laser_AgNPs. Conclusions: Laser_AuNPs and especially AgNPs could be alternatives for managing cariogenic biofilms.