Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 95: Other And Miscellaneous
O 95.3: Vortrag
Donnerstag, 15. März 2018, 12:30–12:45, MA 144
Surface characterisation of bacteria and biofilms with near-ambient pressure X-ray photoelectron spectroscopy — •Marit Kjaervik1, Paul Dietrich2, Andreas Thissen2, Karin Schwibbert1, and Wolfgang Unger1 — 1Bundesanstalt für Materialforschung und -prüfung, Berlin, Germany — 2SPECS Surface Nano Analysis GmbH, Berlin, Germany
The XPS information depth of approximately 10 nm is in the same size range as the outer membrane of the gram-negative bacteria, which makes XPS a suitable tool for determining the elemental composition of the bacterial surface and monitor changes caused by outer stress like dehydration or exposure to antimicrobials. However, bacteria are inherently in a hydrated state, and therefore only compatible to ultra-high vacuum after extensive sample preparation, which may degrade the sample constituents. This issue is addressed by the development of near-ambient pressure (NAP)-XPS, which enables bacteria and biofilms to be characterised in their native wet state. Artificial biofilms, bacteria and biofilms of Escherichia coli have been characterised with the laboratory NAP-XPS instrument EnviroESCA from SPECS GmbH, at pressures ranging from high vacuum to 12 mbar, and in both humid and dry environment. By studying biological samples in their native wet state, new insight about composition and transport of drugs through cell membranes and the extracellular polymeric substance (EPS) of biofilms can be obtained. In this contribution, the latest progress on biofilm characterisation by NAP-XPS will be presented, and measurement capabilities and limitations will be discussed.