Biocidal effect of copper and zinc oxide nanoparticles on human oral microbiome and biofilm formation

Oral cavity bacteria, specifically those involved in biofilm formation and dental ailments, are major health concerns. Thus, the ability of CuO (40 nm) and ZnO (35 nm) nanoparticles (NPs) synthesized in this study was assessed in vitro for inhibition of culturable oral bacteria and their biofilm formation. Both the NPs at a concentration of 50 μg/ml significantly inhibited the growth of total oral bacteria, extracellular polysaccharide (EPS) production and biofilm formation on the glass, acrylic dentures and cultured human epithelial cells, as models. The results elucidated strong bactericidal action of CuO- and ZnO-NPs, which significantly reduces the oral bacterial load and eventually inhibits the growth of oral biofilm colonizers.

► Crystals of CuO-NPs (40 nm) and ZnO-NPs (35 nm) were chemically synthesized. ► Zeta (ζ) potentials of ZnO- and CuO-NPs were 20.8 and 16.4 mV, respectively. ► EC50 values of CuO- and ZnO-NPs were 70.5 and 22.5 μg/ml, respectively, on NA plates. ► 100% oral bacterial biofilm inhibition on glass and acrylic denture with both NPs. ► CuO- and ZnO-NPs may serve as novel antimicrobials for oral biofilm control.