Biofilm destruction by he-O2 RF highpressure cold plasma jet

Summary form only given. Biofilms are populations of microorganisms set in a glue-like matrix mostly composed of exopolysaccharides and a small amount of proteins and nucleic acids. Biofilms play an important role in bacterial pathogenesis in humans, animals, and plants, and in bacterial attachments to surfaces such as in medical devices, dental waterlines, etc. Disinfection and sterilization methods frequently used for microorganisms in free, planktonic life are often ineffective on biofilms. Gas discharge plasmas, composed of a mixture of charged particles, chemically reactive species, and UV radiation are a novel sterilization alternative. The relationship between killing effectiveness and exposure time was studied for 4 day-old biofilm samples treated with an AtomfloTM 250 gas discharge plasma source (Surfx Technologies, CA) operating with He (at 20.4 L/min flow) and O₂ (at 0.400 L/min). Biofilm samples are prepared using Chromobacterium violaceum, a gram negative bacterium commonly present in soil and water. Optical emission spectroscopy is used to study plasma composition and temperature which is then correlated with the killing effectiveness. In addition, the killing effectiveness of the He-O₂ plasma is compared to that reported previously for He-N ₂ plasma