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Sylvie Roke

Cette personne a quitté l’EPFL

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Publications associées (128)

Page 2 sur 7

High throughput wide field second harmonic imaging of giant unilamellar vesicles

Sylvie Roke, Maksim Eremchev, David Roesel, Pierre-Marc Jean Marie Dansette

Cell-sized giant unilamellar vesicles (GUVs) are an ideal tool for understanding lipid membrane structure and properties. Label-free spatiotemporal images of their membrane potential and structure would greatly aid the quantitative understanding of membran ...

AIP Publishing2023

Quantified interface chemistry and biophysics via water imaging

Sylvie Roke

High throughput wide-field second harmonic imaging enables the label-free imaging of interfacial (< 3 nm thick) water, with a spatial resolution of similar to 370 nm using similar to 100 ms acquisition times per image. The obtained interfacial orientationa ...

Spie-Int Soc Optical Engineering2024

Specific Ion Effects at the Interface of Nanometer-Sized Droplets in Water: Structure and Stability

Sylvie Roke, Halil Ibrahim Okur, Evangelia Zdrali

The interaction of ions with interfaces influences numerous processes in chemistry, physics, and biology, while different ion species behave differently at hydrophobic or hydrophilic interfaces. Despite its importance, ion specificity and its relation to s ...

2019

Second-Harmonic Scattering as a Probe of Structural Correlations in Liquids

Michele Ceriotti, Sylvie Roke, David Mark Wilkins, Gabriele Tocci, Chung-Wen Liang

econd-harmonic scattering experiments of water and other bulk molecular liquids have long been assumed to be insensitive to interactions between the molecules. The measured intensity is generally thought to arise from incoherent scattering due to individua ...

Amer Chemical Soc2016

pH drives electron density fluctuations that enhance electric field-induced liquid flow

Sylvie Roke, Saranya Pullanchery Sankara Narayanan, Sergey Kulik, Tereza Schönfeldová

Liquid flow along a charged interface is commonly described by classical continuum theory, which represents the electric double layer by uniformly distributed point charges. The electrophoretic mobility of hydrophobic nanodroplets in water doubles in magni ...

Springer Science and Business Media LLC2024

Hydration mediated interfacial transitions on mixed hydrophobic/hydrophilic nanodroplet interfaces

Sylvie Roke, Halil Ibrahim Okur, Nikolay Smolentsev, Rüdiger Scheu, Filip Kovacik

Interfacial phase transitions are of fundamental importance for climate, industry, and biological processes. In this work, we observe a hydration mediated surface transition in supercooled oil nanodroplets in aqueous solutions using second harmonic and sum ...

2018

Label-free spectroscopic detection of vesicles in water using vibrational sum frequency scattering

Sylvie Roke

Vibrational sum frequency scattering (SFS) has been used to study sub-micron, catanionic vesicles in solution. The vesicles were synthesized from a binary mixture of dodecyltrimethylammonium bromide (DTAB) and sodium dodecylsulfate (SDS) surfactants in deu ...

2011

Comparison of scattering and reflection SFG: a question of phase-matching

Sylvie Roke, Rüdiger Scheu

We present a comparison between sum frequency scattering (SFS) and reflection mode sum frequency generation (R-SFG). We have used scattering theory to describe both scattering experiments as well as reflection mode experiments. The interfacial vibrational ...

2012

Water-Mediated Ion Pairing: Occurrence and Relevance

Sylvie Roke

We present an overview of the studies of ion pairing in aqueous media of the past decade. In these studies, interactions between ions, and between ions and water, are investigated with relatively novel approaches, including dielectric relaxation spectrosco ...

American Chemical Society2016

Ultrasensitive Label-Free Detection of Protein–Membrane Interaction Exemplified by Toxin-Liposome Insertion

Sylvie Roke, Matteo Dal Peraro, Halil Ibrahim Okur, Chan Cao, Mircea Ioan Iacovache, Tereza Schönfeldová

Measuring the high-affinity binding of proteins to liposome membranes remains a challenge. Here, we show an ultrasensitive and direct detection of protein binding to liposome membranes using high throughput second harmonic scattering (SHS). Perfringolysin ...

2022

The Molecular Mechanism of Nanodroplet Stability

Yixing Chen, Sylvie Roke, Halil Ibrahim Okur, David Mark Wilkins, Evangelia Zdrali

Mixtures of nano- and microscopic oil droplets in water have recently been rediscovered as miniature reaction vessels in microfluidic environments and are important constituents of many environmental systems, food, personal care, and medical products. The ...

Amer Chemical Soc2017

Freezing effects of oil-in-water emulsions studied by sum-frequency scattering spectroscopy

Sylvie Roke, Nikolay Smolentsev

Temperature-dependent sum-frequency scattering spectroscopy is used to study the properties of hexadecane and dodecane oil droplets in water. The sum-frequency scattering spectra contain vibrational bands that correspond to the symmetric and antisymmetric ...

Amer Inst Physics2016

Does the ionic distribution in the electrical double layer modify second harmonic scattering?

Sylvie Roke, Arianna Marchioro, Bingxin Chu

Surface-specific nonlinear optical techniques are ideally suited to investigate the complex structure of aqueous interfaces. For colloidal particles dispersed in aqueous solutions, interfacial properties can be retrieved with angle-resolved second harmonic ...

AIP Publishing2024

From Hydrophobic to Hydrophilic: The Structure and Density of the Hexadecane Droplet/Alkanol/Water Interface

Sylvie Roke, Yixing Chen

The molecular structure of the hexadecane droplet/alkanol/water interface has been investigated using vibrational sum frequency scattering and second harmonic scattering. This combination of methods allows us to investigate the interfacial alkyl chain conf ...

American Chemical Society2015

Transient domains of ordered water induced by divalent ions lead to lipid membrane curvature fluctuations

Sylvie Roke, Halil Ibrahim Okur, Orly Bagunu Tarun

Cations influence the electrostatic, chemical and mechanical properties of lipid bilayers. Here, label-free second harmonic microscopy shows that cation-induced transient ordering of water also plays a role in driving membrane curvature fluctuations, linki ...

NATURE PUBLISHING GROUP2020

Analysis of Complex Spectra Using Fourier Filtering

Sylvie Roke, Yixing Chen, Rüdiger Scheu

We present a method to analyze complex spectral data, such as that obtained from vibrational sumfrequency generation (SFG), using Fourier filtering. The proposed filter locates the center frequency of all resonances in a complex data set. The analysis is u ...

Amer Chemical Soc2013

Passive transport of Ca2+ ions through lipid bilayers imaged by widefield second harmonic microscopy

Sylvie Roke, David Roesel, Maksim Eremchev

In biology, release of Ca2+ ions in the cytosol is essential to trigger or control many cell functions. Calcium signaling acutely depends on lipid membrane permeability to Ca2+. For proper understanding of membrane permeability to Ca2+, both membrane hydra ...

2023

Imaging Cu2+ binding to charged phospholipid membranes by high-throughput second harmonic wide-field microscopy

Sylvie Roke, David Roesel, Seonwoo Lee

The interaction of divalent copper ions (Cu2+) with cell membranes is crucial for a variety of physiological processes of cells, such as hormone synthesis and cellular energy production. These interactions would not be possible without membrane hydration. ...

AIP Publishing2021

Specific Ion Effects in Amphiphile Hydration and Interface Stabilization

Sylvie Roke, Yixing Chen, Rüdiger Scheu

Specific ion effects 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 ...

Amer Chemical Soc2014

Vibrational Sum Frequency Scattering in Absorptive Media: A Theoretical Case Study of Nano-objects in Water

Sylvie Roke, Saranya Pullanchery Sankara Narayanan, Sergey Kulik

The structures of interfaces of nano- and microscale objects in an aqueous solution are important for a wide variety of physical, chemical, and biological processes. Vibrational sum frequency (SF) scattering has emerged as a useful and unique probe of the ...

AMER CHEMICAL SOC2020