Antimicrobial Effectiveness of Regular Dielectric- Barrier Discharge (DBD) and Jet DBD on the Viability of Pseudomonas aeruginosa

Bacterial biofilm formation on medical implants is a major cause of illness in patients and is, therefore, increasing healthcare costs due to extended hospital stays and the failure/disposal of contaminated implants. Only limited progress has been made to prevent or eradicate this growing problem. Effective approaches include inhibiting the initiation of biofilm growth by killing planktonic bacteria and breaking down existing biofilms. We propose to employ atmospheric pressure nonthermal regular dielectric-barrier discharge (DBD) and jet plasma to kill bacteria that have been grown planktonically or in biofilms. In this paper, Pseudomonas aeruginosa was grown either planktonically or on titanium coupons in a bioreactor under dynamic conditions to form mature biofilms. The planktonic bacteria and biofilms were exposed to regular DBD and jet plasma and bacterial survival was evaluated after treatment for various times and at different distances. Within 5 min of plasma treatment, we observed complete decontamination of planktonically grown bacteria, and within 15 min, we observed more than a 3 log reduction (99.9%) of bacteria grown as biofilms. The efficacy of plasma treatment was also visualized using scanning electron microscopy, where disruption of biofilm was found with an increasing treatment time. This paper also determined that jet plasma is more effective in treating biofilms than regular DBD plasma.