Publications by Benjamin Rappaz

Automated fast label-free quantification of cardiomyocyte dynamics with raw holograms for cardiotoxicity screening

Traditional cell analysis approaches based on quantitative phase imaging (QPI) necessitate a reconstruction stage, which utilizes digital holography. However, phase retrieval processing can be complicated and time-consuming since it needs numerical reconst ...

Optica Publishing Group2025

Phosphoproteomics and morphology of stored human red blood cells treated by protein tyrosine phosphatases inhibitor

Gerardo Turcatti, Benjamin Rappaz, Florence Armand, Romain Hamelin

The process of protein phosphorylation is involved in numerous cell functions. In particular, phosphotyrosine (pY) has been reported to play a role in red blood cell (RBC) functions, including the cytoskeleton organization. During their storage before tran ...

2023

Automated Dual-Mode Cell Monitoring To Simultaneously Explore Calcium Dynamics and Contraction-Relaxation Kinetics within Drug-Treated Stem Cell-Derived Cardiomyocytes

Gerardo Turcatti, Pierre Marquet, Benjamin Rappaz, Bokyoung Kim

This manuscript proposes a new dual-mode cell imaging system for studying the relationships between calcium dynamics and the contractility process of cardiomyocytes derived from human-induced pluripotent stem cells. Practically, this dual-mode cell imaging ...

AMER CHEMICAL SOC2023

Image- and Fluorescence-Based Test Shows Oxidant-Dependent Damages in Red Blood Cells and Enables Screening of Potential Protective Molecules

Gerardo Turcatti, Michel Prudent, Benjamin Rappaz, Manon Sandra Bardyn, David Crettaz

An increase of oxygen saturation within blood bags and metabolic dysregulation occur during storage of red blood cells (RBCs). It leads to the gradual exhaustion of RBC antioxidant protective system and, consequently, to a deleterious state of oxidative st ...

2021

Marker-Free Automatic Quantification of Drug-Treated Cardiomyocytes with Digital Holographic Imaging

Gerardo Turcatti, Pierre Marquet, Benjamin Rappaz, Fabien Kuttler, Bokyoung Kim

We use quantitative phase digital holographic microscopy (QP-DHM) to image and quantify the beating movement of cardiomyocytes, derived from induced pluripotent stem cells (iPSCs), in control and drug-treated conditions. The development of an analysis algo ...

AMER CHEMICAL SOC2020

Image-Based Marker-Free Screening of GABA(A) Agonists, Antagonists, and Modulators

Gerardo Turcatti, Pierre Marquet, Damiano Banfi, Pascal Jourdain, Benjamin Rappaz, Fabien Kuttler

The ionotropic GABA(A) receptors represent the main target for different groups of widely used drugs having hypnotic and anxiolytic effects. So far, most approaches used to assess GABA activity involve invasive low -throughput electrophysiological techniqu ...

2019

Quantification of stored red blood cell fluctuations by time-lapse holographic cell imaging

Gerardo Turcatti, Pierre Marquet, Michel Prudent, Benjamin Rappaz, Manon Sandra Bardyn

We propose methods to quantitatively calculate the fluctuation rate of red blood cells with nanometric axial and millisecond temporal sensitivity at the single-cell level by using time-lapse holographic cell imaging. For this quantitative analysis, cell me ...

2018

Red blood cells ageing markers: a multi-parametric analysis

Gerardo Turcatti, Michel Prudent, Niels Erik Lion, Benjamin Rappaz, Manon Sandra Bardyn, David Crettaz

Background. Red blood cells collected in citrate-phosphate-dextrose can be stored for up to 42 days at 4 degrees C in saline-adenine-glucose-mannitol additive solution. During this controlled, but nevertheless artificial, ex vivo ageing, red blood cells ac ...

Simti Servizi Srl2017

Quantitative phase-digital holographic microscopy: a new imaging modality to identify original cellular biomarkers of diseases

Christian Depeursinge, Pierre Marquet, Pierre Magistretti, Pascal Jourdain, Benjamin Rappaz, Kaspar Rothenfusser

Quantitative phase microscopy (QPM) has recently emerged as a powerful label-free technique in the field of living cell imaging allowing to non-invasively measure with a nanometric axial sensitivity cell structure and dynamics. Since the phase retardation ...

Spie-Int Soc Optical Engineering2016

Automated tracking of temporal displacements of a red blood cell obtained by time-lapse digital holographic microscopy

Benjamin Rappaz

Red blood cell (RBC) phase images that are numerically reconstructed by digital holographic microscopy (DHM) can describe the cell structure and dynamics information beneficial for a quantitative analysis of RBCs. However, RBCs investigated with time-lapse ...

Optical Soc Amer2016

Automated multi-parameter measurement of cardiomyocytes dynamics with digital holographic microscopy

Gerardo Turcatti, Pierre Marquet, Benjamin Rappaz

Compounds tested during drug development may have adverse effects on the heart; therefore all new chemical entities have to undergo extensive preclinical assessment for cardiac liability. Conventional intensity-based imaging techniques are not robust enoug ...

Optical Society of America2015

Phase Retrieval by Using Transport-of-Intensity Equation and Differential Interference Contrast Microscopy

Michaël Unser, Daniel Sage, Benjamin Rappaz, Emrah Bostan, Emmanuel Augustin Julien Froustey

We present a variational reconstruction algorithm for the phase-retrieval problem by using the differential interference contrast microscopy. Principally, we rely on the transport-of-intensity equation that specifies the sought phase as the solution of a p ...

IEEE2014

Loss of Protein Tyr-phosphorylation During in vitro Storage of Human Erythrocytes: Impact on RBC Morphology

Gerardo Turcatti, Pierre Marquet, Michel Prudent, Niels Erik Lion, Benjamin Rappaz

Wiley-Blackwell2014

Digital holographic microscopy: a quantitative label-free microscopy technique for phenotypic screening

Gerardo Turcatti, Benjamin Rappaz, Etienne Shaffer

Digital Holographic Microscopy (DHM) is a label-free imaging technique allowing visualization of transparent cells with classical imaging cell culture plates. The quantitative DHM phase contrast image provided is related both to the intracellular refractiv ...

2014

Label-Free Cytotoxicity Screening Assay by Digital Holographic Microscopy

Gerardo Turcatti, Christian Depeursinge, Marc Chambon, Jonas Kühn, Pierre Magistretti, Benjamin Rappaz, Julien Mena, Jérôme Parent, Etienne Shaffer

We introduce a label-free technology based on digital holographic microscopy (DHM) with applicability for screening by imaging, and we demonstrate its capability for cytotoxicity assessment using mammalian living cells. For this first high content screenin ...

Mary Ann Liebert2013

Simultaneous Optical Recording in Multiple Cells by Digital Holographic Microscopy of Chloride Current Associated to Activation of the Ligand-Gated Chloride Channel GABA(A) Receptor

Christian Depeursinge, Pierre Marquet, Pascal Jourdain, Daniel Boss, Benjamin Rappaz, Corinne Moratal

Chloride channels represent a group of targets for major clinical indications. However, molecular screening for chloride channel modulators has proven to be difficult and time-consuming as approaches essentially rely on the use of fluorescent dyes or invas ...

Public Library of Science2012

Spatially-Resolved Eigenmode Decomposition of Red Blood Cells Membrane Fluctuations Questions the Role of ATP in Flickering

Christian Depeursinge, Pierre Marquet, Pierre Magistretti, Dimitri Nestor Alice Van De Ville, Annick Hoffmann, Daniel Boss, Benjamin Rappaz

Red blood cells (RBCs) present unique reversible shape deformability, essential for both function and survival, resulting notably in cell membrane fluctuations (CMF). These CMF have been subject of many studies in order to obtain a better understanding of ...

Public Library Science2012

Determination of Transmembrane Water Fluxes in Neurons Elicited by Glutamate Ionotropic Receptors and by the Co-transporters KCC2 and NKCC1: A Digital Holographic Microscopy Study

Christian Depeursinge, Pierre Marquet, Pierre Magistretti, Nicolas Pavillon, Pascal Jourdain, Daniel Boss, Benjamin Rappaz, Corinne Moratal

Digital holographic microscopy (DHM) is a noninvasive optical imaging technique that provides quantitative phase images of living cells. In a recent study, we showed that the quantitative monitoring of the phase signal by DHM was a simple label-free method ...

Society for Neuroscience2011

Red blood cell structure and dynamics explored with digital holographic microscopy

Christian Depeursinge, Pierre Marquet, Pierre Magistretti, Pascal Jourdain, Daniel Boss, Benjamin Rappaz

2009

Spatial analysis of erythrocyte membrane fluctuations by digital holographic microscopy

Christian Depeursinge, Pierre Marquet, Pierre Magistretti, Annick Hoffmann, Daniel Boss, Benjamin Rappaz

Red blood cell (RBC) membrane fluctuations provide important insights into cell states. We present a spatial analysis of red blood cell membrane fluctuations by using digital holographic Microscopy (DHM). This interferometric and dye-free technique, posses ...

Elsevier2009