Plasma Biology

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Biology Low-temperature atmospheric-pressure plasma is a multi-component system that includes such biologically active agents as charged particles, reactive nitrogen and oxygen species, metastable-state molecules or atoms, and UV radiation. The major goal of our research is to investigate the effects of these plasma components, separately and in different combinations, on bacteria, viruses, and different types of human cells. This knowledge would provide a basis for designing purpose-specific plasmas for biomedical applications.

1. Bactericidal and antiviral effects of plasma irradiation

Bactericidal and antiviral properties of plasmas have been intensively studied and utilized for the decontamination and sterilization of medical instruments, catheters, packages, containers and premises. The main difference of plasmas developed in our group from the plasmas used for surface sterilization is that our plasmas are designed for the disinfection of living tissues (e.g. skin and chronic wounds). In order to avoid damaging human cells and tissues, these plasmas should have low temperature (<37°C), low-intensity of UV radiation, and low, micromolar concentrations of reactive species. To identify the sterilizing potential of these ''low-intensity'' plasmas, we are currently testing the effects of plasma irradiation on gram-positive (Enterococcus mundtii and methicillin-resistant Staphylococcus aureus (MRSA)) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria, bacterial spores, pathogenic fungi (Candida albicans), and adenoviruses. Additional experiments include control for the development of plasma resistance and antibiotic resistance in several consequent generations of bacteria which survived the plasma treatment.


Figure 1: Effect of irradiation with air plasma on methicillin-resistant Staphylococcus aureus (MRSA). Four agar plates (the bottom of the picture) were inoculated with approximately 107 bacteria/plate, exposed to plasma produced by the plasma dispenser (the top left picture) for 2s, 5s, 15s and 30s and consequently incubated during 18 hours at 35°C, so that the survived bacteria could reproduce and form colony forming units (CFUs). The number of CFUs corresponds to the number of bacteria, which survived the plasma treatment. For comparison, a control plate containing a 105 dilution of the bacterial inoculate is included (the top right picture). From the results it is clearly visible, that the bactericidal effect of the plasma increases for larger plasma treatment times. Only five seconds of plasma irradiation caused over five orders of magnitude reduction in the MRSA load.

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  1. Effects of plasma irradiation on human cells

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