Abstract
Purpose: :
Plasma is an ionized gas created by the passage of an electric current and it is considered the fourth state of matter after liquid, solid and gaseous. We explored the effects of atmospheric pressure cold plasma (APCP) as a bactericidal system that causes no tissue/corneal damage for possible treatment of corneal infections.
Methods: :
APCP is generated by a new portable device driven by a radiofrequency voltage of hundreds of volts that ionize a flux of helium gas partially mixed with air. Ex vivo porcine corneas, corneal fibroblast cultures and microbial cultures were treated with APCP using different exposure times and energies. The effects were evaluated by morphology, micro-TC, proliferation assay (MTT), and by analyzing the colony forming units (CFU) of Escherichia coli and Staphylococcus aureus cultures.
Results: :
No significant damaging effects were seen on corneas by histology, micro-TC and electron microscopy evaluations after 1 and 2 minutes treatment. Monolayer cell cultures showed dose- and time-dependent morphological and proliferative changes. The number of CFUs after 30", 1’, 2’ and 5’ of treatment was reduced, compared to the control group, by 30%, 65%, 85% and 99,7% for both Escherichia coli and Staphylococcus aureus.
Conclusions: :
Cold plasma using helium/oxygen may have future clinical applications as a sterilization method that elicits no damaging effects to the ocular surface.
Keywords: cornea: clinical science • antibiotics/antifungals/antiparasitics • microbial pathogenesis: experimental studies