Effective bacterial inactivation using low temperature radio frequency plasma.
A Sureshkumar1, R Sankar, Mahitosh Mandal
1Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, West Bengal, India.
International Journal of Pharmaceutics
|July 9, 2010
Summary
This study compared nitrogen and nitrogen-oxygen radiofrequency plasma for sterilizing Staphylococcus aureus. The nitrogen-oxygen mixture plasma demonstrated superior bacterial reduction, achieving a log(10) factor of 6.
Area of Science:
- Microbiology
- Plasma Physics
- Biomedical Engineering
Background:
- Staphylococcus aureus is a leading cause of hospital-acquired infections.
- Effective sterilization methods are crucial for infection control in healthcare settings.
Purpose of the Study:
- To compare the sterilization efficacy of radiofrequency (RF) plasma generated using nitrogen versus a nitrogen-oxygen mixture against Staphylococcus aureus.
- To investigate the mechanisms behind plasma-mediated bacterial inactivation.
Main Methods:
- Exposure of Staphylococcus aureus to 13.56MHz RF plasma generated by nitrogen and a nitrogen-oxygen (2%) mixture.
- Sterilization efficacy assessed by bacterial reduction.
- Mechanism investigation using optical emission spectroscopy (OES) and scanning electron microscopy (SEM).
Main Results:
- Nitrogen plasma showed sterilization effects attributed to ultraviolet (UV) radiation.
- The nitrogen-oxygen mixture plasma demonstrated enhanced sterilization, linked to nitric oxide (NO) emission and other reactive species.
- SEM revealed severe morphological damage to bacterial cells treated with the nitrogen-oxygen plasma.
- A log(10) reduction factor of 6 was achieved with the nitrogen-oxygen plasma after 5 minutes of treatment at 100W RF power.
Conclusions:
- The addition of 2% oxygen to nitrogen plasma significantly enhances its bactericidal efficacy against Staphylococcus aureus.
- Reactive species, including nitric oxide, generated in the nitrogen-oxygen plasma play a key role in bacterial inactivation.
- RF plasma, particularly with a nitrogen-oxygen mixture, shows potential as an effective sterilization technology for combating hospital-acquired infections.
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