The Effect of Gold Nano Particles with Different Sizes on Streptococcus Species

Fatemeh Lavaee; Zahra Ranjbar; Farzan Modaresi; Fatemeh Keshavarz

doi:10.30476/DENTJODS.2021.85219.1119

The Effect of Gold Nano Particles with Different Sizes on Streptococcus Species

J Dent (Shiraz). 2021 Dec;22(4):235-242. doi: 10.30476/DENTJODS.2021.85219.1119.

Authors

Fatemeh Lavaee¹, Zahra Ranjbar², Farzan Modaresi³, Fatemeh Keshavarz⁴

Affiliations

¹ Oral and Dental Disease Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
² Dept. Oral and Maxillofacial Disease, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
³ Dept. of Bacteriology and Virology, Jahrom Medical School, Jahrom University of Medical Sciences, Jahrom, Iran.
⁴ Undergraduate Students, Student Research Committee, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.

Abstract

Statement of the problem: Streptococcus mutans, Streptococcus sanguinis, and Streptococcus salivarius are most common etiologic bacteria for dental caries. Different sizes of gold nanoparticles may have different antibacterial effects on these species.

Purpose: This study aimed to compare the antibacterial effect of chlorhexidine and three sizes of gold nano particles (25, 60, 90nm) against clinical and standard strains of Streptococcus mutans, Streptococcus sanguinis, and Streptococcus salivarius.

Materials and method: In this cross-sectional study, the specimens were collected from 75 children aged 3-5 years old. Antibacterial effect of chlorhexidine and three sizes of gold nano particles (25, 60, 90nm) were investigated by evaluating the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against three bacterial strains.

Results: The MIC and MBC of gold nanoparticles with different sizes against Streptococcus mutans, Streptococcus sanguinis, and Streptococcus salivarius were statistically different. The MIC and MBC of smaller gold nano particles (25nm) were significantly lower (p<0.001) than larger ones. Patient-derived bacteria had significantly higher values of MIC and MBC in comparison to standard species (p<0.001).

Conclusion: The results of this study confirmed the significant size-dependency of gold nano particles for antibacterial activity. As the size of gold nano particles decrease, the antibacterial properties enhance.

Keywords: Nanoparticles; Streptococcus mutans; Streptococcus salivarius; Streptococcus sanguinis.