Abstract
Purpose: :
A prototype of a plasma (ionized gases) source, operating at low power and atmospheric pressure, has been developed to treat corneal infections. The sterilizing effect may be due to the formation of atomic and molecular free radicals (ROS) and/or by UV emission. We investigated the effects of the plasma on different microorganisms, human cells and cornea.
Methods: :
Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans were used as prototype bacterial pathogens. The plasma’s effects on human fibroblasts were assessed by MTT assay, ROS and thymine dimer expression and, in the whole human cornea, by transmission and electron microscopy.
Results: :
Anti-microbial activity was directly dependent on exposure time. Following an application of plasma for 2 minutes, a significant reduction of bacterial viability was observed. Spectrometry revealed a very low UV emission by this plasma source prototype. Treatment of human cells with plasma did not cause any significant vitality reduction, and no thymine formation was observed. ROS production in human cell cultures was high within 5 minutes after plasma treatment, but reduced by 100% after 30 minutes. No morphological damage was found in the cornea after plasma treatment.
Conclusions: :
Cold plasma reduces microorganism but not human cell viability, producing ROS. Low UV emission did not cause DNA damage to human cells. We continue studying this plasma source as a potential new tool in ophthalmologic practice for treating cornel infections.
Keywords: bacterial disease • oxidation/oxidative or free radical damage • radiation damage: light/UV