Antimicrobial activity of nanoemulsion on cariogenic Streptococcus mutans

Ramalingam Karthikeyan, Bennett T. Amaechi, H. Ralph Rawls, Valerie A. Lee

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


Objective: To assess antimicrobial activities of nanoemulsion (NE) to control the adhesion and biofilm formation by Streptococcus mutans by in vitro. Design: In vitro antimicrobial susceptibility of nanoemulsion was determined as per National Committee for Clinical Laboratory Standards guidelines and agar diffusion, serial dilution technique for the determination of minimum inhibitory concentration and minimum bactericidal concentration (MIC/MBC). Efficacy was tested by kinetics of killing, biofilm assay and scanning electron microscopy. Results: : NE concentrations ranging from 1:100 to 1:10,000 dilutions were effective against S. mutans as shown through MIC/MBC assays. NE showed antimicrobial activity against planktonic cells at high dilutions, confirmed by time kill studies. 4-day-old S. mutans biofilms were treated with NE; subsequent reductions of bacterial cell counts were noticed with decreasing dilutions. Staining of NE-treated biofilms with LIVE/DEAD BacLight resulted in dead cell areas of up to 48% in 1 min, 84% at 1 h and significant (<0.05) increases in dead cell counts at all time points. Damage to cell membranes and cell walls of S. mutans by NE was demonstrated using scanning electron microscopy (SEM). Conclusion: These results suggest that nanoemulsion has effective antibacterial activity against S. mutans and may be a useful medication in the prevention of dental caries.

Original languageEnglish (US)
Pages (from-to)437-445
Number of pages9
JournalArchives of Oral Biology
Issue number5
StatePublished - May 2011


  • Adhesion
  • Anticaries agen
  • Biofilm
  • Dental caries
  • Nanoemulsion
  • Streptococcus mutans

ASJC Scopus subject areas

  • Otorhinolaryngology
  • Dentistry(all)
  • Cell Biology


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