La division Spectroscopies d'Electrons de la Société Française du Vide vous invite à participer à son 3e Webinaire le vendredi 25 novembre 2022 à 10h pour une durée de 45 mn, sur le thème :

Cryogenic XPS enabling surface analysis of hydrated soft materials such as microorganisms"
Présenté par 
Madeleine Ramstedt (Department of Chemistry, Umeå University, Sweden)

Short bio:

  • PhD at Department of Chemistry, Umeå University, 2004
  • Postdocs at Ecole Polytechnique Federal de Lausanne, Material Science, Switzerland, 2005 and  at University of Cambridge, Department of Chemistry, UK, 2006-2007
  • Assistant professor at Department of Chemistry, Umeå University, 2008 – 2012
  • Associate professor at Department of Chemistry, Umeå University, 2012 – current

Please find more info on my web page:

This webinar will show work that we have performed at Umeå University enabling surface analysis of hydrated – but frozen- microorganisms. We have observed that cryo-XPS maintains the structural organization of soft hydrated materials better than if the same samples are analysed at room temperature in dehydrated form. Using cryogenic XPS (cryo-XPS), we have analysed the surface chemical composition for a range of microbial cells. I will show examples from bacterial cells, algal cells, fungi and viruses (bacteriophages). To support in data analysis, we have also analysed a large range of standard substances that form building blocks of microbial cell wall. We have also developed a methodology for using the C1s spectrum of a sample to predict the relative content of C atoms in substances with a character resembling lipids, polysaccharide or peptide (protein or peptidoglycan). I will present comparative studies between cryo-XPS and near ambient pressure XPS on bacterial cells. Overall, I hope to illustrate that cryo-XPS can play a very important role in surface characterization of soft hydrated materials such as biological systems, polymers and drug delivery platforms.