Research project
The surface chemical composition of microorganisms can be analyzed using several different methods. We have been developing methodology for cryogenic X-ray photoelectron spectroscopy (cryo-XPS) applications on microorganisms.
The goal of the method development is to enable XPS surface analyses of biological specimens without desiccation that may risk to alter the surface composition of the sample.
This methodology involves analyzing fast-frozen intact microbial cells (i.e. not freeze dried or dehydrated) under liquid nitrogen temperatures. We thereafter use a spectral model to predict the content of lipid, polysaccharide and peptide (protein + peptidoglycan) in the outermost part of the intact microbial cell wall from the C1s spectrum. We have used this approach on bacteria (both Gram-positive and Gram-negative), phages, algae and fungal cells.
This work has been funded through grants from Umeå Center for Microbial Research and the Kempe Foundation. It has been conducted at the XPS platform at Umeå University.
This method development has taken place during several years in collaboration with other researchers at Umeå universitet, e.g. Andrey Shchukarev, Jean-François Boily, Bernt-Erik Uhlin, Sun Nuynt Wai, Christiane Funk, Constantin Urban. Also international colaborators have been important partners in this work e.g. Ryoma Nakao at National Institute of Infectious Diseases, Tokyo, Japan and Stefan Salentinig at University of Fribourg, Schweiz.
In 2022 we also investigated application of this methodology to investigate nanoparticles together with colleagues at the National Physical Laboratory in UK, David Cant, Caterina Minelli and Alex Shard.