Publications de Sylvia Jeney | EPFL Graph Search

Filamentous and step-like behavior of gelling coarse fibrin networks revealed by high-frequency microrheology

By a micro-experimental methodology, we study the ongoing molecular process inside coarse fibrin networks by means of microrheology. We made these networks gelate around a probe microbead, allowing us to observe a temporal evolution compatible with the wel ...

ROYAL SOC CHEMISTRY2020

Interplay between optical, viscous, and elastic forces on an optically trapped Brownian particle immersed in a viscoelastic fluid

László Forró, Sylvia Jeney

We provide a detailed study of the interplay between the different interactions which appear in the Brownian motion of a micronsized sphere immersed in a viscoelastic fluid measured with optical trapping interferometry. To explore a wide range of viscous, ...

Amer Inst Physics2016

Single potassium niobate nano/microsized particles as local mechano-optical Brownian probes

László Forró, Andrzej Sienkiewicz, Sylvia Jeney, Arnaud Magrez, Flavio Maurizio Mor

Perovskite alkaline niobates, due to their strong nonlinear optical properties, including birefringence and the capability to produce second-harmonic generation (SHG) signals, attract a lot of attention as potential candidates for applications as local nan ...

Royal Soc Chemistry2016

Calibration of optical tweezers with non-spherical probes via high-resolution detection of Brownian motion

László Forró, Richard Gaal, Sylvia Jeney, Flavio Maurizio Mor

Optical tweezers are commonly used and powerful tools to perform force measurements on the piconewton scale and to detect nanometer-scaled displacements. However, the precision of these instruments relies to a great extent on the accuracy of the calibratio ...

Elsevier Science Bv2015

Red Blood Cell Aging During Storage, Studied Using Optical Tweezers Experiment

Sylvia Jeney, Hanieh Mohammadi

This paper presents experimental and numerical studies of erythrocyte stretching, with a focus on the aging of red blood cells in an in vitro environment during storage. The experimental studies were performed using optical tweezers. The laser beam was use ...

Springer2015

Upconversion Particle as a Local Luminescent Brownian Probe: A Photonic Force Microscopy Study

László Forró, Andrzej Sienkiewicz, Sylvia Jeney, Flavio Maurizio Mor

Near-infrared (NIR) light sensitive lanthanide-doped NaYF4 upconversion particles (UCPs) are gaining increasing attention as local probes in biomedical applications. Here, we implemented a photonic force microscope (PFM) to manipulate and study the optical ...

Amer Chemical Soc2014

Accounting for inertia effects to access the high-frequency microrheology of viscoelastic fluids

László Forró, Sylvia Jeney, Frank Scheffold, Elena Bertseva

We study the Brownian motion of microbeads immersed in water and in a viscoelastic wormlike micelles solution by optical trapping interferometry and diffusing wave spectroscopy. Through the mean-square displacement obtained from both techniques, we deduce ...

Amer Physical Soc2014

Contact Angle at the Leading Edge Controls Cell Protrusion Rate

László Forró, Jean-Jacques Meister, Alexander Verkhovskiy, Sylvia Jeney, Chiara Gabella, Elena Bertseva, Niccolo Piacentini, Alicia Carine Bornert

Plasma membrane tension and the pressure generated by actin polymerization are two antagonistic forces believed to define the protrusion rate at the leading edge of migrating cells [1-5]. Quantitatively, resistance to actin protrusion is a product of membr ...

Elsevier2014

Selective transport control on molecular velcro made from intrinsically disordered proteins

Sylvia Jeney

The selectivity and speed of many biological transport processes(1) transpire from a 'reduction of dimensionality'(2) that confines diffusion to one or two dimensions instead of three(3). This behaviour remains highly sought after on polymeric surfaces(4) ...

Nature Publishing Group2014

Exploiting the color of Brownian motion for high-frequency microrheology of Newtonian fluids

László Forró, Sylvia Jeney, Flavio Maurizio Mor

Einstein's stochastic description of the random movement of small objects in a fluid, i.e. Brownian motion, reveals to be quite different, when observed on short timescales. The limitations of Einstein's theory with respect to particle inertia and hydrodyn ...

Spie-Int Soc Optical Engineering2013

Hydrodynamic and subdiffusive motion of tracers in a viscoelastic medium

László Forró, Sylvia Jeney, Elena Bertseva

We investigate the diffusive motion of micron-sized spherical tracers in a viscoelastic actin filament network over the time span of 8 orders of magnitude using optical-tweezers single-particle tracking. The hydrodynamic interactions of a tracer with the s ...

Amer Physical Soc2013

High-resolution detection of Brownian motion for quantitative optical tweezers experiments

Sylvia Jeney, Matthias Grimm

We have developed an in situ method to calibrate optical tweezers experiments and simultaneously measure the size of the trapped particle or the viscosity of the surrounding fluid. The positional fluctuations of the trapped particle are recorded with a hig ...

Amer Physical Soc2012

Optical trapping microrheology in cultured human cells

László Forró, Sylvia Jeney, Elena Bertseva

We present the microrheological study of the two close human epithelial cell lines: non-cancerous HCV29 and cancerous T24. The optical tweezers tracking was applied to extract the several seconds long trajectories of endogenous lipid granules at time step ...

Springer-Verlag2012

Brownian motion in a Maxwell fluid

Sylvia Jeney, Matthias Grimm

The equilibrium dynamics of a spherical particle immersed in a complex Maxwell fluid is analyzed in terms of velocity autocorrelation function (VACF), mean-square displacement (MSD), and power spectral density (PSD). We elucidate the role of hydrodynamic m ...

Royal Society of Chemistry2011

Synchrotron Infrared Microspectroscopy Detecting the Evolution of Huntington's Disease Neuropathology and Suggesting Unique Correlates of Dysfunction in White versus Gray Brain Matter

László Forró, Sylvia Jeney, Heike Runne, Markus Bonda

Huntington's disease (HD), caused by a mutation of the corresponding gene encoding the protein huntingtin (htt), is characterized by progressive deterioration of cognitive and motor functions, paralleled by extensive loss of striatal neurons. At the cellul ...

2011

Resonances arising from hydrodynamic memory in Brownian motion

László Forró, Sylvia Jeney, Giuseppe Foffi, Flavio Maurizio Mor, Maxim Belushkin, Matthias Grimm

Observation of the Brownian motion of a small probe interacting with its environment provides one of the main strategies for characterizing soft matter. Essentially, two counteracting forces govern the motion of the Brownian particle. First, the particle i ...

2011

Direct observation of the full transition from ballistic to diffusive Brownian motion in a liquid

Branimir Lukic, Sylvia Jeney

At timescales once deemed immeasurably small by Einstein, the random movement of Brownian particles in a liquid is expected to be replaced by ballistic motion. So far, an experimental verification of this prediction has been out of reach due to a lack of i ...

2011

Evidence of lipid peroxidation and protein phosphorylation in cells upon oxidative stress photo-generated by fullerols

László Forró, Andrzej Sienkiewicz, Sylvia Jeney

An oxidative stress (OS) state is characterized by the generation of Reactive Oxygen Species (ROS) in a biological system above its capacity to counterbalance them [1]. Exposure to OS induces the accumulation of intracellular ROS, which in turn causes cell ...

Elsevier2010

Intracellular nanomanipulation by a photonic-force microscope with real-time acquisition of a 3D stiffness matrix

László Forró, Gérard Gremaud, Andrzej Kulik, Philippe Thévenaz, Michaël Unser, Giovanni Dietler, Stefania Puttini, Sylvia Jeney, Elena Bertseva, Amardeep Singh

A traditional photonic-force microscope (PFM) results in huge sets of data, which requires tedious numerical analysis. In this paper, we propose instead an analog signal processor to attain real-time capabilities while retaining the richness of the traditi ...

Institute of Physics2009

Persistent correlation of constrained colloidal motion

Sylvia Jeney

We have investigated the motion of a single optically trapped colloidal particle close to a limiting wall at time scales where the inertia of the surrounding fluid plays a significant role. The velocity autocorrelation function exhibits a complex interplay ...

2009