title: Improvement of Biological Indicators by Uniformly Distributing Bacillus subtilis Spores in Monolayers To Evaluate Enhanced Spore Decontamination Technologies.
abstract: Novel decontamination technologies, including cold low-pressure plasma and blue light (400 nm), are promising alternatives to conventional surface decontamination methods. However, the standardization of the assessment of such sterilization processes remains to be accomplished. Bacterial endospores of the genera Bacillus and Geobacillus are frequently used as biological indicators (BIs) of sterility. Ensuring standardized and reproducible BIs for reliable testing procedures is a significant problem in industrial settings. In this study, an electrically driven spray deposition device was developed, allowing fast, reproducible, and homogeneous preparation of Bacillus subtilis 168 spore monolayers on glass surfaces. A detailed description of the structural design as well as the operating principle of the spraying device is given. The reproducible formation of spore monolayers of up to 5 × 10(7) spores per sample was verified by scanning electron microscopy. Surface inactivation studies revealed that monolayered spores were inactivated by UV-C (254 nm), low-pressure argon plasma (500 W, 10 Pa, 100 standard cubic cm per min), and blue light (400 nm) significantly faster than multilayered spores were. We have thus succeeded in the uniform preparation of reproducible, highly concentrated spore monolayers with the potential to generate BIs for a variety of nonpenetrating surface decontamination techniques.
authors.affiliation: German Aerospace Center (DLR e.V.), Institute of Aerospace Medicine, Radiation Biology Department, Space Microbiology Research Group, Cologne, Germany.
authors.forename: Marina
authors.initials: M
authors.lastname: Raguse
authors.affiliation: Ruhr University Bochum, Institute of Electrical Engineering and Plasma Technology, Faculty of Electrical Engineering and Information Technology, Bochum, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Fiebrandt
authors.affiliation: Ruhr University Bochum, Institute of Electrical Engineering and Plasma Technology, Biomedical Applications of Plasma Technology, Bochum, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Stapelmann
authors.affiliation: Robert Koch Institute, Advanced Light and Electron Microscopy, Berlin, Germany.
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Madela
authors.affiliation: Robert Koch Institute, Advanced Light and Electron Microscopy, Berlin, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Laue
authors.affiliation: Ruhr University Bochum, Institute of Electrical Engineering and Plasma Technology, Faculty of Electrical Engineering and Information Technology, Bochum, Germany.|Ruhr University Bochum, Institute of Electrical Engineering and Plasma Technology, Biomedical Applications of Plasma Technology, Bochum, Germany.
authors.forename: Jan-Wilm
authors.initials: JW
authors.lastname: Lackmann
authors.affiliation: Defence Science and Technology Laboratory, Chemical, Biological and Radiological Division, Salisbury, United Kingdom.
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Thwaite
authors.affiliation: University of Connecticut Health Center, Department of Molecular Biology and Biophysics, Farmington, Connecticut, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Setlow
authors.affiliation: Ruhr University Bochum, Institute of Electrical Engineering and Plasma Technology, Faculty of Electrical Engineering and Information Technology, Bochum, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Awakowicz
authors.affiliation: German Aerospace Center (DLR e.V.), Institute of Aerospace Medicine, Radiation Biology Department, Space Microbiology Research Group, Cologne, Germany ralf.moeller@dlr.de.
authors.forename: Ralf
authors.initials: R
authors.lastname: Moeller
mesh_terms: D001412:Bacillus subtilis / Q000254:growth & development / Q000528:radiation effects*; D003666:Decontamination / Q000295:instrumentation / Q000379:methods*; D011312:Pressure; D013171:Spores, Bacterial / Q000254:growth & development / Q000528:radiation effects*; D014466:Ultraviolet Rays