Synthesis of hybrid copper-chitosan nanoparticles with antibacterial activity against cariogenic Streptococcus mutans

Hybrid nanoparticles (CuChNP) comprising of copper nanoparticles with a chitosan shell were synthesized. Antimicrobial properties of CuChNP were assessed against Streptococcus mutans (S. mutans), one of the main bacterium that causes tooth decay. Antibacterial activity of CuChNP against S. mutans was comparable to that of oral antimicrobial agents, such as chlorhexidine, and cetylpyridinium chloride. Particularly, CuChNP exhibited superior capacity to prevent the S. mutans growth on human tooth surface as well as disrupt and kill the bacterial cells in an established dental biofilm. Chitosan may interact with both tooth hydroxyapatite and bacterial cell wall, which improves the adherence of copper to the tooth surface and potentiates their anti-biofilm action. The antimicrobial properties exhibited by CuChNP could be useful for the future development of more effective treatments for the control of dental plaque biofilms.