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Sylvie Roke

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Related publications (128)

Page 3 of 7

Surface Potential and Interfacial Water Order at the Amorphous TiO2 Nanoparticle/Aqueous Interface

Sylvie Roke, Arianna Marchioro, Marie Bischoff

Colloidal nanoparticles exhibit unique size-dependent properties differing from their bulk counterpart, which can be particularly relevant for catalytic applications. To optimize surface-mediated chemical reactions, the understanding of the microscopic str ...

2020

Label-free and charge-sensitive dynamic imaging of lipid membrane hydration on millisecond time scales

Sylvie Roke, Orly Bagunu Tarun

Biological membranes are highly dynamic and complex lipid bilayers, responsible for the fate of living cells. To achieve this function, the hydrating environment is crucial. However, membrane imaging typically neglects water, focusing on the insertion of p ...

2018

Membrane water for probing neuronal membrane potentials and ionic fluxes at the single cell level

Pierre Magistretti, Sylvie Roke, Orly Bagunu Tarun, Pascal Jourdain, Marie Eve Pascale Didier

Neurons communicate through electrochemical signaling within a complex network. These signals are composed of changes in membrane potentials and are traditionally measured with the aid of (toxic) fluorescent labels or invasive electrical probes. Here, we d ...

Nature Publishing Group2018

What interactions can distort the orientational distribution of interfacial water molecules as probed by second harmonic and sum frequency generation?

Sylvie Roke

Aqueous interfaces are omnipresent in nature. Nonlinear optical methods such as second harmonic and sum frequency generation (SHG/SFG) are valuable techniques to access molecular level information from these interfaces. In the interpretation of SHG and SFG ...

American Institute of Physics2016

Stern Layer Formation Induced by Hydrophobic Interactions: A Molecular Level Study

Sylvie Roke, Yixing Chen, Rüdiger Scheu

The molecular ionic surface structure and charge of the electric double layer around a nanodroplet and its structural change induced by hydrophobic effects are measured using vibrational coherent surface scattering spectroscopy, second harmonic scattering, ...

Amer Chemical Soc2013

Mapping Electrochemical Heterogeneity at Gold Surfaces: A Second Harmonic Imaging Study

Sylvie Roke, Arianna Marchioro, Igor Nahálka

Designing efficient catalysts requires correlating surface structure and local chemical composition with reactivity on length scales from nanometers to tens of microns. While much work has been done on this structure/function correlation on single crystals ...

2020

High throughput second harmonic imaging for label-free biological applications

Pierre Magistretti, Pierre Marquet, Aleksandra Radenovic, Sylvie Roke, Pascal Jourdain, Orly Bagunu Tarun, Carlos Alberto Macias Romero, Vitalijs Zubkovs, Marie Eve Pascale Didier

Second harmonic generation (SHG) is inherently sensitive to the absence of spatial centrosymmetry, which can render it intrinsically sensitive to interfacial processes, chemical changes and electrochemical responses. Here, we seek to improve the imaging th ...

Optical Society of America2014

Spatiotemporal Imaging of Water in Operating Voltage-Gated Ion Channels Reveals the Slow Motion of Interfacial Ions

Sylvie Roke, Aleksandra Radenovic, Orly Bagunu Tarun, Maksim Eremchev

Ion channels are responsible for numerous physiological functions ranging from transport to chemical and electrical signaling. Although static ion channel structure has been studied following a structural biology approach, spatiotemporal investigation of t ...

American Chemical Society (ACS)2019

Endogenous SHG and 2PEF coherence imaging of substructures in neurons in 3D

Sylvie Roke, Carlos Alberto Macias Romero, Marie Eve Pascale Didier, Claire Jacqueline Léa Teulon

Neuronal morphology, long-distance transport and signalling critically depend on the organization of microtubules in the cytoskeleton. Second harmonic generation (SHG) imaging has been recognized as a potentially powerful tool for in situ label-free neuroi ...

2019

Nonlinear spectroscopy of bio-interfaces

Sylvie Roke

In the past five years the Max Planck Research Group for Nonlinear spectroscopy of bio-interfaces has worked at the intersection of surface science, nonlinear optics and soft and biological matter. For hard matter there is molecular level understanding of ...

2011

Ion-Induced Transient Potential Fluctuations Facilitate Pore Formation and Cation Transport through Lipid Membranes

Sylvie Roke, David Roesel, Maksim Eremchev

Unassisted ion transport through lipid membranes plays a crucial role in many cell functions without which life would not be possible, yet the precise mechanism behind the process remains unknown due to its molecular complexity. Here, we demonstrate a dire ...

2022

Charge Asymmetry at Aqueous Hydrophobic Interfaces and Hydration Shells

Sylvie Roke, Yixing Chen, Rüdiger Scheu

The solvation of ions in a dielectric continuum is symmetric with respect to the sign of the ionic charge. Yet, many phenomena show indirect evidence that water may have a preference for negative charge: the vast majority of biological membrane interfaces ...

Wiley-Blackwell2014

Dissecting the hydrogen bond network of water: Charge transfer and nuclear quantum effects

Sylvie Roke, David Mark Wilkins, Mischa Samuel Flór

The molecular structure of water is dynamic, with intermolecular hydrogen (H) bond interactions being modified by both electronic charge transfer and nuclear quantum effects (NQEs). Electronic charge transfer and NQEs potentially change under acidic or bas ...

American Association for the Advancement of Science2024

The interfacial structure of nano-and micron-sized oil and water droplets stabilized with SDS and Span80

Sylvie Roke, Esther Amstad, Nikolay Smolentsev, Evangelia Zdrali, Gianluca Nicolas Etienne

In this work, we provide a comparison between the stability and the interfacial structure of micrometer-sized and nanometer-sized droplets by employing a multi-instrumental approach comprised of the surface-sensitive technique of sum frequency scattering a ...

2019

Polycation Interactions with Zwitterionic Phospholipid Monolayers on Oil Nanodroplets Suspensions in Water (D2O) Probed by Sum Frequency Scattering

Sylvie Roke, Nikolay Smolentsev

By combining dynamic light scattering (DLS) measurements and infrared (IR) spectroscopy with the interface- and bond-specificity of vibrational sum frequency generation scattering (SFS) spectroscopy, we probe several structural aspects of how zwitterionic ...

2018

Temperature dependence of water-water and ion-water correlations in bulk water and electrolyte solutions probed by femtosecond elastic second harmonic scattering

Yixing Chen, Sylvie Roke, Halil Ibrahim Okur, Nathan Dupertuis

The temperature dependence of the femtosecond elastic second harmonic scattering (fs-ESHS) response of bulk light and heavy water and their electrolyte solutions is presented. We observe clear temperature dependent changes in the hydrogen (H)-bond network ...

2018

Sum frequency spectroscopy of the hydrophobic nanodroplet/water interface: Absence of hydroxyl ion and dangling OH bond signatures

Sylvie Roke, Nikolay Smolentsev, Rüdiger Scheu

Vibrational sum frequency scattering measurements were performed on deuterated hexadecane oil nanodroplets dispersed in aqueous pH neutral and basic solutions. The predominant symmetry of the observed vibrational signatures was derived using nonlinear ligh ...

Elsevier2014

Biodegradable Harmonophores for Targeted High-Resolution In Vivo Tumor Imaging

Sylvie Roke, Claire Jacqueline Léa Teulon

Optical imaging probes have played a major role in detecting and monitoring a variety of diseases. In particular, nonlinear optical imaging probes, such as second harmonic generating (SHG) nanoprobes, hold great promise as clinical contrast agents, as they ...

2021

Mapping of real-time morphological changes in the neuronal cytoskeleton with label-free wide-field second-harmonic imaging: a case study of nocodazole

Sylvie Roke, Pascal Jourdain, Carlos Alberto Macias Romero, Marie Eve Pascale Didier, Claire Jacqueline Léa Teulon

We demonstrate the use of wide-field high-throughput second-harmonic (SH) microscopy for investigating cytoskeletal morphological changes on the single-cell level. The method allows for real-time, in vitro, label-free measurements of cytoskeletal changes t ...

SPIE-Intl Soc Optical Eng2019

Intermolecular Headgroup Interaction and Hydration as Driving Forces for Lipid Transmembrane Asymmetry

Sylvie Roke, Halil Ibrahim Okur, Nikolay Smolentsev, Cornelis Ulrich Lütgebaucks

Variations between the inner and outer leaflets of cell membranes are crucial for cell functioning and signaling, drug–membrane interactions, and the formation of lipid domains. Transmembrane asymmetry can in principle be comprised of an asymmetric charge ...

American Chemical Society2016