Non-Thermal Plasma Sources Based on Cometary and Point-to-Ring Discharges

Area of Science:

• Plasma physics
• Microbiology
• Antimicrobial research

Background:

• Microbial resistance to conventional drugs necessitates novel therapeutic strategies.
• Non-thermal plasma (NTP) has emerged as a promising tool for treating bacterial, viral, and fungal infections.
• Investigating different NTP generation methods is crucial for optimizing antimicrobial applications.

Purpose of the Study:

• To compare the physical and microbicidal properties of two distinct non-thermal plasma (NTP) sources.
• To evaluate the efficacy of these NTP sources against various microbial strains, including resistant bacteria and fungi.
• To characterize the electrical and emission properties influencing the microbicidal activity of NTP.

Main Methods:

• Generated and characterized two NTP sources: cometary discharge (point-to-point) and corona discharge (point-to-ring).
• Assessed electrical and emission properties of both plasma sources.
• Tested microbicidal effects on Staphylococcus aureus (including MRSA), Pseudomonas aeruginosa, Candida albicans, and Trichophyton interdigitale using agar diffusion assays.

Main Results:

• Cometary discharge NTP was less stable, producing smaller, faster inhibition zones.
• Point-to-ring discharge NTP offered greater stability with larger, though not always complete, inhibition zones.
• After 60 minutes, both NTP sources demonstrated comparable microbicidal effects on bacteria, with varied impacts on fungi.

Conclusions:

• Both cometary and point-to-ring non-thermal plasma discharges show potential as antimicrobial agents.
• The choice of NTP source configuration influences stability and zone of inhibition.
• Further research is warranted to optimize NTP for specific microbial targets, particularly fungi.