Plasma inactivation of microbial Biofilms

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Aging societies as well as the increase of antibiotic resistant bacteria lead to rising requirements in the sterilization of medical products. Especially, modern plastics cannot be sterilized with established sterilization procedures or only a few times. Furthermore, the number of surgical, blood stream, and urinary tract infections due to vancomycin resistant bacteria increased significantly in the last years. As 80 % of all bacterial infection are associated to biofilm forming bacteria, we want to investigate the applicability of low-pressure and atmospheric pressure plasmas for inactivation of microbial biofilms.In this research project we want to investigate the inactivation mechanisms of low-pressure and atmospheric pressure plasmas as well as the protection mechanisms of microbial biofilms. Regarding the plasma, two plasma sources will be used with completely different properties. One setup is a low-pressure source which inactivation efficiency of bacterial spores is mainly based on high energetic radiation rather chemical modifications. The second setup comprises an atmospheric pressure source where the inactivation is dominated by chemical reactions due to the absence of high energetic UV-C radiation. Therewith, we will be able to investigate the influence of high energetic radiation and radicals separately. By varying the gas mixtures as well as the pressure of the plasma sources, it will be possible to generate plasmas showing both quantities and analyse possible synergistic effects. In the biological part of the project, we will produce spores and biofilms of Bacillus subtilis bacteria which are commonly used for the verification of sterilization efficiencies. In particular, we want to investigate the inactivation and protection mechanisms, e.g. DNA repair, which occurs after plasma treatment. By using different incubation conditions and bacterial mutants harbouring deficiencies in DNA-repair or biofilm formation related genes, as well as by varying the plasma conditions, different contamination scenarios can be investigated. In the frame of this project we want to analyse the potential of plasma-based sterilization applications for the inactivation of microbial biofilms in the medical sector to understand the inactivation mechanisms. Results of this project will redefine the future of plasma research to prophylactically counteract potential microbiological hazards as well as curb real contaminants.