Plasma inactivation of microbial Biofilms

老龄化社会以及抗生素耐药细菌的增加导致对医疗产品灭菌的要求不断提高。特别是，现代塑料不能用既定的灭菌程序或只有几次灭菌。此外，万古霉素耐药细菌引起的手术、血流和尿路感染的数量在过去几年中显著增加。由于80%的细菌感染与形成生物膜的细菌有关，我们想研究低压和常压等离子体对微生物生物膜灭活的适用性。本课题旨在研究低压和常压等离子体的失活机制以及微生物生物膜的保护机制。关于等离子体，两种等离子体源将使用完全不同的特性。一种设置是低压源，细菌孢子的灭活效率主要基于高能量辐射而不是化学修饰。第二种装置包括一个大气压源，其中由于缺乏高能UV-C辐射，失活主要由化学反应控制。这样，我们就可以分别研究高能辐射和自由基的影响。通过改变气体混合物以及等离子体源的压力，将有可能产生显示数量和分析可能的协同效应的等离子体。在项目的生物部分，我们将生产枯草芽孢杆菌的孢子和生物膜，这些细菌通常用于灭菌效率的验证。特别是，我们希望研究血浆治疗后发生的失活和保护机制，例如DNA修复。通过使用不同的培养条件和携带dna修复或生物膜形成相关基因缺陷的细菌突变体，以及通过改变血浆条件，可以研究不同的污染情况。在这个项目的框架内，我们想分析基于等离子体的灭菌应用在医疗部门微生物生物膜灭活的潜力，以了解灭活机制。该项目的结果将重新定义等离子体研究的未来，以预防性地抵消潜在的微生物危害，并遏制真正的污染物。

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.