Microbial Inactivation in the Liquid Phase Induced by Multigas Plasma Jet

Area of Science:

• Plasma physics
• Microbiology
• Biophysics

Background:

• Atmospheric nonthermal plasmas are emerging as a powerful tool for microbial inactivation.
• Understanding the specific reactive species responsible for sterilization is crucial for optimizing plasma-based disinfection technologies.

Purpose of the Study:

• To investigate the sterilization efficacy of various gas atmospheric nonthermal plasmas.
• To identify the primary reactive species responsible for microbial inactivation by these plasmas.

Main Methods:

• Generation of nonthermal plasmas using a multigas plasma jet.
• Treatment of microbial suspensions with carbon dioxide and nitrogen plasmas.
• Addition of antioxidants to identify key reactive species responsible for inactivation.

Main Results:

• Carbon dioxide and nitrogen plasmas exhibited significant sterilization effects on microbial suspensions.
• Carbon dioxide plasma produced abundant singlet oxygen, effectively killing bacteria and fungi.
• Nitrogen plasma generated substantial hydroxyl radicals, leading to a ≥ 6 log reduction of 11 diverse microbial species within 1-15 minutes.
• Antioxidant experiments confirmed singlet oxygen and hydroxyl radicals as the primary agents of bacterial inactivation.

Conclusions:

• Atmospheric nonthermal plasmas, particularly those utilizing carbon dioxide and nitrogen, offer potent sterilization capabilities.
• Singlet oxygen and hydroxyl radicals are the principal reactive species mediating microbial inactivation by these plasmas.
• These findings provide a foundation for developing targeted plasma-based sterilization strategies.