The influence of a non-thermal plasma (NTP) on the gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, the gram-positive bacterium Staphylococcus epidermidis, and the yeast Candida albicans grown on agar or in the biofilm form was compared. NTP was produced by a DC cometary discharge.
The biofilms were grown on the surface of Ti-6Al-4V alloy often used in the manufacture of prosthetic implants. The exposure by NTP not only inhibited the surface growth of microorganisms in agar cultures but also significantly suppressed the viability of bacteria and yeast in biofilms and prevented its re-developed from persistent cells remaining in the lower layers of the biofilm.
An almost complete prevention of biofilm re-development was achieved in the case of S. epidermidis; other microorganisms displayed substantial lowering of biofilm biomass and its metabolic activity.