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Sylvie Roke

Sylvie Roke

Member from 2010 to 2015
subject: Biophotonics

Contact
Laboratory for fundamental BioPhotonics Lausanne (Schweiz)
EPFL-STI-IBI-LBP Building BM 4112, Station 17
CH-1015 Lausanne

Tel.: +41 (21) 69 33 11 91
sylvie.roke@epfl.ch

Personal web page

Research Areas

  • Non-linear optics and non-linear dispersion of light

  • Soft matter and nano- and micro-particle systems

  • Structure, kinetics and dynamics of ultrafast spectroscopy

 

Curriculum Vitae

  • 2014-2019

    European Research Council Consolidator Grant

  • Cover and Featured Professional in the 2013-2014 SPIE Monthly Planner. The planner promotes optics worldwide (~10.000 printed copies, 25 countries)

  • since 2011

    Julia Jacobi Chair for Photomedicine

  • 2009-2014

    European Research Council Startup Grant

  • 2008

    Hertha Sponer Prize of the German Physical Society

  • 2006

    Minerva Prize of the Netherlands Foundation for Research of Matter (FOM)

  • 2005-2012

    Max Planck Future Scientist Group Leader at the MPI for Metal Research in Stuttgart

  • 2005

    Alexander von Humboldt Fellow at the University of Heidelberg

  • 2005

    Postdoctoral Fellow at the FOM Institute for Plasma Physics Rijnhuizen in Nieuwegein (NL)

  • 2003

    L. J. Oosterhoff Prize of the University of Leiden (NL)

  • 2000-2004

    Ph.D. in Natural Sciences at the University of Leiden (NL)

  • 1997-2000

    Master's Degree Programme in Physics at the University of Utrecht (NL)

  • 1995-2000

    Master's Degree Programme in Chemistry at the University of Utrecht (NL)

Featured Publication

Specific ion effects in surfactant hydration and nanodroplet stabilization R. Scheu, H. B. de Aguiar, B. M. Rankin, D. Ben-Amotz, S. Roke J. Am. Chem. Soc., 2014, 136, 2040–2047

Specific ion effects in surfactant hydration and nanodroplet stabilization R. Scheu, H. B. de Aguiar, B. M. Rankin, D. Ben-Amotz, S. Roke J. Am. Chem. Soc., 2014, 136, 2040–2047

Specific ion effects in amphiphile hydration and interface stabilization Rüdiger Scheu1, Yixing Chen1, Hilton B de Aguiar1, Blake M Rankin2, Dor Ben-Amotz2, Sylvie Roke1# 1Laboratory for fundamental BioPhotonics (LBP), Institute of Bio-engineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland, #sylvie.roke@epfl.ch; 2Purdue University, Department of Chemistry, West Lafayette, Indiana 47907, USA. Table salt, NaCl tastes salty. KCl, tastes slightly different, and KSCN another simple salt, is lethal at very small doses. These effects are examples of specific ion effects that are commonly occurring in chemical and biochemical processes involving salt solutions. Specific ion effects involve the specific interactions of ions with water and surfaces, and can influence many processes in aqueous solutions: protein folding, enzyme activity, self-assembly, and interface stabilization. Ionic amphiphiles are known to stabilize the oil/water interface, presumably by dipping their hydrophobic tails into the oil phase while sticking their hydrophilic head groups in water. We find that also for this seemingly well understood phenomenon specific ion effects play a very important and unexpected role: We find that anionic and cationic amphiphiles adopt strikingly different structures at liquid hydrophobic/water interfaces, linked to the different specific interactions between water and the amphiphile head groups, both at the interface and in the bulk. Vibrational sum frequency scattering measurements show that dodecylsulfate (DS-) ions do not detectably perturb the oil phase while dodecyltrimethylammonium (DTA+) ions do. Raman solvation shell spectroscopy and second harmonic scattering (SHS) show that the respective hydration shells and the interfacial water structure are also very different. Our work (that is only possible thanks to the development of novel approaches and instrumentation) suggests that specific interactions with water play a key role in driving the anionic head group towards the water phase and the cationic head group towards the oil phase, thus also implying a quite different surface stabilization mechanism – something that has previously not been foreseen: instead of forming a packed layer that is mainly determined by geometrical effects as is commonly assumed (and written in many text books), the chemical nature and charge of the ionic head group and its specific interaction with both water and the hydrophobic chemical groups play an important role. Our findings have significant consequences of how we think about membrane formation, peptide and protein folding and stabilization.

Activities

Publications

  • The Interfacial Tension of Nanoscopic Oil Droplets in Water Is Hardly Affected by SDS Surfactant

    S. Roke, H.B. de Aguiar, A.G.F. de Beer, M.L. Strader: The Interfacial Tension of Nanoscopic Oil Droplets in Water Is Hardly Affected by SDS Surfactant. In: J. Am. Chem. Soc. 132 (2010), S. 2122-2123.

  • Nonlinear optical spectroscopy of soft matter interfaces

    S. Roke: Nonlinear optical spectroscopy of soft matter interfaces. In: ChemPhysChem 10 (2009), S. 1380-1388.

  • Detection of buried microstructures by nonlinear optical scattering spectroscopy

    S. Roke, A.G.F. de Beer, H.B. de Aguiar, J.F.W. Nijsen: Detection of buried microstructures by nonlinear optical scattering spectroscopy. In: Phys. Rev. Lett. 102 (2009), 095502-1-4.

  • Delocalized surface modes reveal 3-dimensional structure of complex bio-molecules

    S. Roke, A.B. Sugiharto, C.M. Johnson, I.E. Dunlop: Delocalized surface modes reveal 3-dimensional structure of complex bio-molecules. In: J. Phys. Chem. C, 112, (2008), S. 7531 -7534.

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