The Antimicrobial Property of Plasma Activated Liquids (PALs) against Oral Bacteria Streptococcus mutans

¹Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO 65211, USA

²Nanova, Inc., Columbia, MO 65202, USA

³Department of Internal Medicine, University of Missouri, Columbia, MO 65211, USA

⁴Center for Research on Interfacial Structure & Properties, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO 64108, USA

*Corresponding author: Dr. Qingsong Yu, Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO 65211, USA; E-mail: [email protected]

Received Date: December 03, 2020

Publication Date: May 30, 2021

ABSTRACT

Objective: The ability of plasma activated liquids (PALs) to disinfect oral bacteria in both planktonic and biofilm forms were investigated.

Material and Methods: Phosphate-buffered saline (PBS) and 0.9% saline liquids were activated by non-thermal atmospheric pressure plasma treatment to produce antimicrobial PALs. These PALs were then used to culture oral bacteria Streptococcus mutans (S. mutans) in both planktonic and biofilm forms. The antimicrobial efficacy was assessed by MTT (3-4,5-Dimethylthiazol-2,5-Diphenyltetrazolium Bromide) and colony forming unit (CFU) assays. The data was evaluated by One-way ANOVA statistical analysis.

Results: The PALs could inactivate 38% of the planktonic bacteria and induce 25% biofilm reduction. It was further found that the PALs aged for 24 hours were not effective on bacterial disinfection. However, PALs were found to be non-toxic for mammalian cells. No viability change of fibroblast cells was detected in PALs. Hydrogen peroxide content increased in PALs than that in untreated liquids.

Conclusion: The PALs showed instant antimicrobial effects on oral bacteria of S. mutans in both planktonic and biofilm forms. However, PALs could not completely disinfect all the bacteria and were not able to inhibit the bacteria recovery. It was also found that the PALs were non-toxic to mammalian cells.

KEYWORDS: Dental biofilms; Plasma Activated Liquids; Plasma-liquid Interactions; Antimicrobial