[Low temperature oxygen plasma sterilization effect on pseudomonas aeruginosa]

Area of Science:

• Biomedical Engineering
• Plasma Science
• Microbiology

Background:

• Sterilization of medical devices and materials is critical.
• Low-temperature plasma offers a non-thermal sterilization method.
• Understanding plasma-sterilization mechanisms is essential for optimizing processes.

Purpose of the Study:

• To investigate the sterilization efficacy of low-temperature oxygen plasma on Pseudomonas aeruginosa.
• To analyze the role of different plasma regions (discharge, afterglow, remote) in sterilization.
• To elucidate the mechanisms of plasma-mediated bacterial inactivation.

Main Methods:

• Utilized a self-designed low-temperature oxygen plasma reactor.
• Examined bacterial cell morphology using Scanning Electron Microscopy (SEM).
• Quantified protein content using the Coomassie Blue technique.
• Measured electron/ion temperature with a double Langmuir probe.
• Determined free radical concentration via electron spin resonance spectroscopy.

Main Results:

• Achieved significant germicidal effects in all three plasma areas within 30 seconds.
• SEM revealed plasma-induced cell wall and membrane damage, leading to content leakage.
• Identified electrons, ions, and oxygen free radicals as key sterilizing agents in the discharge area.
• Demonstrated that oxygen free radicals are the primary sterilizing species in the afterglow and remote areas.

Conclusions:

• The developed reactor effectively separates active plasma species.
• Confirmed the critical role of oxygen free radicals in remote plasma sterilization.
• Provided insights into the mechanisms of plasma sterilization in different plasma zones.