Oral bacterial deactivation using a low-temperature atmospheric argon plasma brush

Abstract

Summary Objectives To study the plasma treatment effects on deactivation effectiveness of oral bacteria. Methods A low temperature atmospheric argon plasma brush were used to study the oral bacterial deactivation effects in terms of plasma conditions, plasma exposure time, and bacterial supporting media. Oral bacteria of Streptococcus mutans and Lactobacillus acidophilus with an initial bacterial population density between 1.0 × 108 and 5.0 × 108 cfu/ml were seeded on various media and their survivability with plasma exposure was examined. Scanning electron microscopy was used to examine the morphological changes of the plasma treated bacteria. Optical absorption was used to determine the leakage of intracellular proteins and DNAs of the plasma treated bacteria. Results The experimental data indicated that the argon atmospheric plasma brush was very effective in deactivating oral bacteria. The plasma exposure time for a 99.9999% cell reduction was less than 15 seconds for S. mutans and within 5 minutes for L. acidophilus. It was found that the plasma deactivation efficiency was also dependent on the bacterial supporting media. With plasma exposure, significant damages to bacterial cell structures were observed with both bacterium species. Leakage of intracellular proteins and DNAs after plasma exposure was observed through monitoring the absorbance peaks at wavelengths of 280nm and 260nm, respectively. Conclusion The experimental results from this study indicated that low temperature atmospheric plasma treatment was very effective in deactivation of oral bacteria and could be a promising technique in various dental clinical applications such as bacterial disinfection and caries early prevention, etc.

Photodynamic and Tissue Tolerable Plasma Therapies as Alternatives to Antimicrobials to Control Pathogenic Biofilms

“…Thus, bacterial size and structure may affect plasma effectiveness in bacterial deactivation. Yang et al [68] reported the bactericidal effect of TTP on S. mutans and L. acidophilus, which are major pathogens in dental caries. The results indicated that TTP treatment was very effective in the disinfection of oral bacteria.…”

“…They found that L. acidophilus killing needed a longer TTP exposure when compared with S. mutans. One of the hypotheses is that L. acidophilus presents a larger cell (≅1 μm×3 μm), which could mean higher plasma tolerance when compared with the smaller S. mutans(≅1 μm in diameter) [68]. To accomplish the same killing intensity, up to 5 min of TTP exposure was necessary to deactivate L. acidophilus, which is contrary to the 10 s of TTP exposure needed to kill S. mutans.…”

“…In the same study [68], free-floating planktonic S. mutans and L. acidophilus were exposed to argon plasma for different periods of time. Leakage of intracellular proteins and nucleic acid related to bacterial killing were accessed by a UV-visible spectrometer.…”

Terminal sterilization: Conventional methods versus emerging cold atmospheric pressure plasma technology for non‐viable biological tissues

“…CAP technologies have been used effectively to eliminate microorganisms on living tissues in several clinical applications [8,80,[94][95][96][97][98][99][100][101] , including inactivation and eradication of fungi, and vegetative and spore-forming bacteria. [86,89,102] The microbial inactivation effect of CAP can be attained by direct exposure to both the ignited plasma discharge products such as ROS, RNS, UV radiation, or indirectly through the long-lived species that are capable to reach the treated substrate without the electric field effect [91] .…”

Remineralizing effect of cold plasma and/or bioglass on demineralized enamel

“…Yang et al 11) investigated the bactericidal effect of a non-thermal atmospheric-pressure plasma brush on S. mutans and L. acidophilus, which are major pathogens in dental caries. Their results indicated that cold plasmas were effective in deactivating oral bacteria in culture after 5 min of application, this might play some roles in prevention or treatment of dental caries.…”