2017 年 9 巻 2 号 p. 77-82
Metal nanoparticles (NPs) exhibit increasing potential in infection control of oral bacteria, as well as in prevention of plaque formation. However, the detailed antibacterial effects of a variety of NPs are not known. The objective of this study was to evaluate the biofilm formation and bacterial viability of the oral bacterium, Streptococcus mutans (S. mutans), upon exposure to platinum NPs (PtNPs). In addition, micromorphological analyses were performed to evaluate the biological interaction between PtNPs and S. mutans bacteria, using a transmission electron microscope (TEM). PtNPs stabilized by polyacrylic acid (3.7 nm diameter) were used in this study. S. mutans was exposed to PtNPs at various concentrations in growth medium. After the 24 h, biofilm formation and bacterial viability were measured. TEM examinations showed that the presence of PtNPs was sporadic in the biofilm. However, PtNPs adhered to the bacterial surfaces. PtNPs exhibited an inhibitory effect on biofilm formation.