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Jean-luc Aider

ESPCI ParisTech, Laboratoire PMMH - Physique et Mécanique des Milieux Hétérogènes, Research Director at CNRS

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I am a CNRS (French National Science Research Center) Research Director. I work in the PMMH Laboratory, hosted in the ESPCI Paris, a french research engineers school.My research fields are acoustofluidics, microfluidics, biophysics, fluid mechanics, flow control, hydrodynamic instabilities and transition to turbulence. Most of my research activity is now devoted to acoustofluidics. My work is mainly experimental, but I am familiar with CFD.I am aslo co-founder of a biotech startup called Aenitis Technologies. We develop new devices using acoutophoresis to separate various types of cells for cell therapy.

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University of Pecs

Arizona State University

University of Southampton

Marten Darmawan

Atma Jaya Catholic University of Indonesia

Assiut University

Harijono Djojodihardjo

Institut Teknologi Bandung

Marcelo Brígido

Universidade de Brasília - UnB

Shahrokh Sepehri Rahnama

National University of Singapore

University of California, Los Angeles

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Papers by Jean-luc Aider

Influence of Microgravity on Spontaneous Calcium Activity of Primary Hippocampal Neurons

Research Square (Research Square), Sep 20, 2023

The influence of variations of gravity, either hypergravity or microgravity, on the brain of astr... more The influence of variations of gravity, either hypergravity or microgravity, on the brain of astronauts is a major concern for long journeys in space, to the Moon or to Mars, or simply long-duration missions in the ISS. Monitoring brain activity, before and after ISS missions already demonstrated important and long term effects on the brains of astronauts. In this study, we focus on the influence of gravity at the cell level on primary hippocampal neurons. A dedicated setup has been designed and built to perform live calcium imaging during parabolic flights. Using this technology, throughout the CNES parabolic flights campaign, organized by Novespace in spring 2022, we were able to observe neurons inside microfluidic devices and monitor their calcium activity during gravity changes over different parabolas. Our preliminary results clearly indicate a modification of the calcium activity associated to variations of gravity.

Influence of microgravity on spontaneous calcium activity of primary hippocampal neurons grown in microfluidic chips

NPJ microgravity, Feb 6, 2024

Etude des tourbillons de gortler et de leur influence sur le transport d'un scalaire passif en regimes laminaire et turbulent

Nous nous interessons ici a l'influence de tourbillons longitudinaux sur le transport d'u... more Nous nous interessons ici a l'influence de tourbillons longitudinaux sur le transport d'un scalaire passif, a la fois dans les regimes laminaires et turbulent. Ces structures sont creees dans une couche limite sur une paroi concave. La premiere partie de ce travail a consiste a caracteriser leur champ de vitesse, ainsi que leur croissance spatiale, dans les cas stationnaire et instationnaire. On a pu aussi voir leur forte influence sur le transfert de masse dans la couche limite. Enfin nous avons montre comment la presence de ces structures en regime turbulent modifie fortement les statistiques des fluctuations de concentration et de vitesse longitudinale. Les fonctions de distribution de probabilites de ces grandeurs presentent des queues exponentielles dans les regions de couche limite, et ont une forme gaussienne au centre du canal. De meme les fonctions de structures font apparaitre des exposants anormaux, dependant lineairement de l'ordre des fonctions de structure. Enfin les spectres de scalaire se comportent en 1/k, contrairement aux theories classiques sur ce sujet. Tous ont ete obtenus experimentalement par des techniques mises au point au laboratoire, ou bien numeriquement. Les resultats obtenus pour le scalaire en regime turbulent ont ete analyses a l'aide de moyennes conditionnelles, dont certaines se revelent avoir des comportements universels. Ainsi la moyenne de la derivee seconde d'un signal x(t) conditionnee a x depent lineairement de x. Ces resultats semblent valider certains modeles decrivant la turbulence a la fois en terme de fonction de structure et de moyennes conditionnelles

Towards concentric topology in organoids: Structuration and culture of brain derived spheroids in a Bulk Acoustic Wave resonator

HAL (Le Centre pour la Communication Scientifique Directe), Oct 23, 2022

New tools and methods to control the way organoids self-organize or differentiate have recently a... more New tools and methods to control the way organoids self-organize or differentiate have recently arisen as it becomes more and more necessary to cultivate and analyze them in a reproducible manner. Here, we propose a new method using acoustic levitation to grow brain organoids from both primary neurons and patient derived glioblastomas and structure them with a concentric topology, reproducing the architecture found in vivo.

Study of the influence of microgravity on brain derived spheroids in acoustic levitation

HAL (Le Centre pour la Communication Scientifique Directe), Sep 6, 2022

Acoustic levitation of cells generates self-organized spheroids-on-chip during long-term culture

HAL (Le Centre pour la Communication Scientifique Directe), Jul 4, 2022

Characterization and control of a broadband acoustic cavity: Application to cells spheroids manipulation

HAL (Le Centre pour la Communication Scientifique Directe), Oct 19, 2022

Characterization of the natural and forced recirculation bubble downstream a Backward-Facing Step using real-time optical flow velocimetry

HAL (Le Centre pour la Communication Scientifique Directe), Aug 29, 2022

Des mesures par Particle Image Velocimetry en temps-réel (TR-PIV), basée sur un algorithme de flo... more Des mesures par Particle Image Velocimetry en temps-réel (TR-PIV), basée sur un algorithme de flot optique, sont effectuées en aval d'une marche descendante. Cela permet de calculer en temps-réel l'aire instantanée de la bulle de recirculation de l'écoulement naturel dans un plan horizontal. L'évolution de l'aire de la bulle de reciruclation instantanée peut ainsi être engegistrée pendant des temps longs (plusieurs heures) à une fréquence relativement élevée (40 Hz). Plusieurs fréquences naturelles, y compris de très basses fréquences, sont ainsi déterminées. L'écoulement est ensuite contrôlé au moyen de Jet Vortex Generators continus ou pulsés. Les géométries des buses de sorties des jets permettent de générer des paires de tourbillons longitudinaux contrarotatifs qui viennent perturber la couche limite juste en amont de l'arête de la marche. Les mesures par TR-PIV permettent également une évaluation rapide de l'effet de la fréquence d'actionnement pour différents nombres de Reynolds (Re h = [1500 : 2000]). Les résultats montrent que l'excitation de la couche limite en amont du bord, avec une fréquence d'actionnement proche de la fréquence de l'écoulement naturel, conduit à une forte réduction de la zone de recirculation (jusqu'à-60%) dans le plan d'observation.

Real-time planar flow velocity measurements using an optical flow algorithm implemented on GPU

arXiv (Cornell University), Jun 11, 2013

This paper presents a high speed implementation of an optical flow algorithm which computes plana... more This paper presents a high speed implementation of an optical flow algorithm which computes planar velocity fields in an experimental flow. Real-time computation of the flow velocity field allows the experimentalist to have instantaneous access to quantitative features of the flow. This can be very useful in many situations: fast evaluation of the performances and characteristics of a new setup, design optimization, easier and faster parametric studies, etc. It can also be a valuable measurement tool for closed-loop flow control experiments where fast estimation of the state of the flow is needed. The algorithm is implemented on a Graphics Processor Unit (GPU). The accuracy of the computation is shown. Computation speed and scalability of the processing are highlighted along with guidelines for further improvements. The system architecture is flexible, scalable and can be adapted on the fly in order to process higher resolutions or achieve higher precision. The setup is applied on a Backward-Facing Step (BFS) flow in a hydrodynamic channel. For validation purposes, classical Particle Image Velocimetry (PIV) is used to compare with instantaneous optical flow measurements. The important flow characteristics, like the dynamics of the recirculation bubble computed in real-time, are well recovered. Accuracy of real-time optical flow measurements is comparable to off-line PIV computations.

Author Correction: Self‑organization and culture of Mesenchymal Stem Cell spheroids in acoustic levitation

Scientific Reports, Jun 15, 2021

Self-organization and culture of Mesenchymal Stromal Cell spheroids in acoustic levitation

bioRxiv (Cold Spring Harbor Laboratory), Nov 16, 2020

In recent years, 3D cell culture models such as spheroid or organoid technologies have known impo... more In recent years, 3D cell culture models such as spheroid or organoid technologies have known important developments. Many studies have shown that 3D cultures exhibit better biomimetic properties compared to 2D cultures. These properties are important for in-vitro modeling systems, as well as for in-vivo cell therapies and tissue engineering approaches. A reliable use of 3D cellular models still requires standardized protocols with well-controlled and reproducible parameters. To address this challenge, a robust and scaffold-free approach is proposed, which relies on multi-trap acoustic levitation. This technology is successfully applied to Mesenchymal Stromal Cells (MSCs) maintained in acoustic levitation over a 24-hour period. During the culture, MSCs spontaneously self-organized from cell sheets to cell spheroids with a characteristic time of about ten hours. Each acoustofluidic chip could contain up to 30 spheroids in acoustic levitation and four chips could be ran in parallel, leading to the production of 120 spheroids per experiment. Various biological characterizations showed that the cells inside the spheroids were viable, maintained the expression of their cell surface markers and had a higher differentiation capacity compared to standard 2D culture conditions. These results open the path to long-time cell culture in acoustic levitation of cell sheets or spheroids for any type of cells.

Prediction of the dynamics of a backward-facing step flow using focused time-delay neural networks and particle image velocimetry data-sets

International Journal of Heat and Fluid Flow, Apr 1, 2020

The objective of this experimental work was to evaluate the potential of an artificial Neural Net... more The objective of this experimental work was to evaluate the potential of an artificial Neural Network (NN) to predict the full-field dynamics of a standard separated, noise-amplifier flow: the Backward-Facing Step (BFS) flow at = Re 1385 h. Different upstream local visual sensors, based on the velocity fields measured by timeresolved Particle Image Velocimetry, were tested as inputs for the Neural Network. The dynamic coefficients of a Proper Orthogonal Decomposition (POD) were defined as goals-outputs for this non-linear mapping. The coefficients time-series were predicted and the instantaneous velocity fields were reconstructed with satisfying accuracy with a Focused Time-Delay Neural Network (FTDNN). Using a time-delay appears like a crucial choice to ensure an accurate prediction of the dynamics of the BFS flow. A shallow FDTNN is sufficient to obtain good accuracy with low computational time. The influence of the choices of inputs-sensors, the size of the training data-set, the number of neurons in the hidden layer as well as the sensor delay on the accuracy of the predicted flow are discussed for this experimental fluid system.

Culture of cell spheroids in acoustic levitation

HAL (Le Centre pour la Communication Scientifique Directe), Jun 27, 2022

Frequency lock closed-loop control of a separated flow using visual feedback

arXiv (Cornell University), Nov 4, 2013

In this study, a simple model based closed-loop algorithm is used to control the separated flow d... more In this study, a simple model based closed-loop algorithm is used to control the separated flow downstream a backward-facing step. It has been shown in previous studies that the recirculation bubble can be minimized when exciting the shear layer at its natural Kelvin-Helmholtz instability frequency. In this experiment, the natural shedding frequency is identified through real-time analysis of 2D velocity fields. Actuation (pulsed jet) is then locked on this frequency. If flow characteristics stray too far from a set point, shedding frequency is updated and actuation changed. The present work demonstrates the efficacy and robustness of this approach in reducing recirculation while Reynolds number is randomly varied between 1400 and 2800.

Bulk acoustic waves-based system for a rapid and high throughput cell washing

HAL (Le Centre pour la Communication Scientifique Directe), Oct 19, 2022

Sensitivity of a backward facing step flow to the modification of the upstream boundary layer using LES simulations

HAL (Le Centre pour la Communication Scientifique Directe), Sep 19, 2006

International audienc

System identification using Neural Networks applied to experimental noise-amplifier flows characterized by real-time optical flow velocimetry

HAL (Le Centre pour la Communication Scientifique Directe), Sep 3, 2019

Cluster structuration of particle mixture in multi-node acoustic levitation with optical exclusion

HAL (Le Centre pour la Communication Scientifique Directe), Aug 26, 2020

Acoustic reconcentration or separation of cells

HAL (Le Centre pour la Communication Scientifique Directe), Sep 27, 2020

Fabrication of 2D monolayers and 3D spheroids of cells in acoustic levitation

HAL (Le Centre pour la Communication Scientifique Directe), Sep 27, 2020

Influence of Microgravity on Spontaneous Calcium Activity of Primary Hippocampal Neurons

Research Square (Research Square), Sep 20, 2023

The influence of variations of gravity, either hypergravity or microgravity, on the brain of astr... more The influence of variations of gravity, either hypergravity or microgravity, on the brain of astronauts is a major concern for long journeys in space, to the Moon or to Mars, or simply long-duration missions in the ISS. Monitoring brain activity, before and after ISS missions already demonstrated important and long term effects on the brains of astronauts. In this study, we focus on the influence of gravity at the cell level on primary hippocampal neurons. A dedicated setup has been designed and built to perform live calcium imaging during parabolic flights. Using this technology, throughout the CNES parabolic flights campaign, organized by Novespace in spring 2022, we were able to observe neurons inside microfluidic devices and monitor their calcium activity during gravity changes over different parabolas. Our preliminary results clearly indicate a modification of the calcium activity associated to variations of gravity.

Influence of microgravity on spontaneous calcium activity of primary hippocampal neurons grown in microfluidic chips

NPJ microgravity, Feb 6, 2024

Etude des tourbillons de gortler et de leur influence sur le transport d'un scalaire passif en regimes laminaire et turbulent

Nous nous interessons ici a l'influence de tourbillons longitudinaux sur le transport d'u... more Nous nous interessons ici a l'influence de tourbillons longitudinaux sur le transport d'un scalaire passif, a la fois dans les regimes laminaires et turbulent. Ces structures sont creees dans une couche limite sur une paroi concave. La premiere partie de ce travail a consiste a caracteriser leur champ de vitesse, ainsi que leur croissance spatiale, dans les cas stationnaire et instationnaire. On a pu aussi voir leur forte influence sur le transfert de masse dans la couche limite. Enfin nous avons montre comment la presence de ces structures en regime turbulent modifie fortement les statistiques des fluctuations de concentration et de vitesse longitudinale. Les fonctions de distribution de probabilites de ces grandeurs presentent des queues exponentielles dans les regions de couche limite, et ont une forme gaussienne au centre du canal. De meme les fonctions de structures font apparaitre des exposants anormaux, dependant lineairement de l'ordre des fonctions de structure. Enfin les spectres de scalaire se comportent en 1/k, contrairement aux theories classiques sur ce sujet. Tous ont ete obtenus experimentalement par des techniques mises au point au laboratoire, ou bien numeriquement. Les resultats obtenus pour le scalaire en regime turbulent ont ete analyses a l'aide de moyennes conditionnelles, dont certaines se revelent avoir des comportements universels. Ainsi la moyenne de la derivee seconde d'un signal x(t) conditionnee a x depent lineairement de x. Ces resultats semblent valider certains modeles decrivant la turbulence a la fois en terme de fonction de structure et de moyennes conditionnelles

Towards concentric topology in organoids: Structuration and culture of brain derived spheroids in a Bulk Acoustic Wave resonator

HAL (Le Centre pour la Communication Scientifique Directe), Oct 23, 2022

New tools and methods to control the way organoids self-organize or differentiate have recently a... more New tools and methods to control the way organoids self-organize or differentiate have recently arisen as it becomes more and more necessary to cultivate and analyze them in a reproducible manner. Here, we propose a new method using acoustic levitation to grow brain organoids from both primary neurons and patient derived glioblastomas and structure them with a concentric topology, reproducing the architecture found in vivo.

Study of the influence of microgravity on brain derived spheroids in acoustic levitation

HAL (Le Centre pour la Communication Scientifique Directe), Sep 6, 2022

Acoustic levitation of cells generates self-organized spheroids-on-chip during long-term culture

HAL (Le Centre pour la Communication Scientifique Directe), Jul 4, 2022

Characterization and control of a broadband acoustic cavity: Application to cells spheroids manipulation

HAL (Le Centre pour la Communication Scientifique Directe), Oct 19, 2022

Characterization of the natural and forced recirculation bubble downstream a Backward-Facing Step using real-time optical flow velocimetry

HAL (Le Centre pour la Communication Scientifique Directe), Aug 29, 2022

Des mesures par Particle Image Velocimetry en temps-réel (TR-PIV), basée sur un algorithme de flo... more Des mesures par Particle Image Velocimetry en temps-réel (TR-PIV), basée sur un algorithme de flot optique, sont effectuées en aval d'une marche descendante. Cela permet de calculer en temps-réel l'aire instantanée de la bulle de recirculation de l'écoulement naturel dans un plan horizontal. L'évolution de l'aire de la bulle de reciruclation instantanée peut ainsi être engegistrée pendant des temps longs (plusieurs heures) à une fréquence relativement élevée (40 Hz). Plusieurs fréquences naturelles, y compris de très basses fréquences, sont ainsi déterminées. L'écoulement est ensuite contrôlé au moyen de Jet Vortex Generators continus ou pulsés. Les géométries des buses de sorties des jets permettent de générer des paires de tourbillons longitudinaux contrarotatifs qui viennent perturber la couche limite juste en amont de l'arête de la marche. Les mesures par TR-PIV permettent également une évaluation rapide de l'effet de la fréquence d'actionnement pour différents nombres de Reynolds (Re h = [1500 : 2000]). Les résultats montrent que l'excitation de la couche limite en amont du bord, avec une fréquence d'actionnement proche de la fréquence de l'écoulement naturel, conduit à une forte réduction de la zone de recirculation (jusqu'à-60%) dans le plan d'observation.

Real-time planar flow velocity measurements using an optical flow algorithm implemented on GPU

arXiv (Cornell University), Jun 11, 2013

This paper presents a high speed implementation of an optical flow algorithm which computes plana... more This paper presents a high speed implementation of an optical flow algorithm which computes planar velocity fields in an experimental flow. Real-time computation of the flow velocity field allows the experimentalist to have instantaneous access to quantitative features of the flow. This can be very useful in many situations: fast evaluation of the performances and characteristics of a new setup, design optimization, easier and faster parametric studies, etc. It can also be a valuable measurement tool for closed-loop flow control experiments where fast estimation of the state of the flow is needed. The algorithm is implemented on a Graphics Processor Unit (GPU). The accuracy of the computation is shown. Computation speed and scalability of the processing are highlighted along with guidelines for further improvements. The system architecture is flexible, scalable and can be adapted on the fly in order to process higher resolutions or achieve higher precision. The setup is applied on a Backward-Facing Step (BFS) flow in a hydrodynamic channel. For validation purposes, classical Particle Image Velocimetry (PIV) is used to compare with instantaneous optical flow measurements. The important flow characteristics, like the dynamics of the recirculation bubble computed in real-time, are well recovered. Accuracy of real-time optical flow measurements is comparable to off-line PIV computations.

Author Correction: Self‑organization and culture of Mesenchymal Stem Cell spheroids in acoustic levitation

Scientific Reports, Jun 15, 2021

Self-organization and culture of Mesenchymal Stromal Cell spheroids in acoustic levitation

bioRxiv (Cold Spring Harbor Laboratory), Nov 16, 2020

In recent years, 3D cell culture models such as spheroid or organoid technologies have known impo... more In recent years, 3D cell culture models such as spheroid or organoid technologies have known important developments. Many studies have shown that 3D cultures exhibit better biomimetic properties compared to 2D cultures. These properties are important for in-vitro modeling systems, as well as for in-vivo cell therapies and tissue engineering approaches. A reliable use of 3D cellular models still requires standardized protocols with well-controlled and reproducible parameters. To address this challenge, a robust and scaffold-free approach is proposed, which relies on multi-trap acoustic levitation. This technology is successfully applied to Mesenchymal Stromal Cells (MSCs) maintained in acoustic levitation over a 24-hour period. During the culture, MSCs spontaneously self-organized from cell sheets to cell spheroids with a characteristic time of about ten hours. Each acoustofluidic chip could contain up to 30 spheroids in acoustic levitation and four chips could be ran in parallel, leading to the production of 120 spheroids per experiment. Various biological characterizations showed that the cells inside the spheroids were viable, maintained the expression of their cell surface markers and had a higher differentiation capacity compared to standard 2D culture conditions. These results open the path to long-time cell culture in acoustic levitation of cell sheets or spheroids for any type of cells.

Prediction of the dynamics of a backward-facing step flow using focused time-delay neural networks and particle image velocimetry data-sets

International Journal of Heat and Fluid Flow, Apr 1, 2020

The objective of this experimental work was to evaluate the potential of an artificial Neural Net... more The objective of this experimental work was to evaluate the potential of an artificial Neural Network (NN) to predict the full-field dynamics of a standard separated, noise-amplifier flow: the Backward-Facing Step (BFS) flow at = Re 1385 h. Different upstream local visual sensors, based on the velocity fields measured by timeresolved Particle Image Velocimetry, were tested as inputs for the Neural Network. The dynamic coefficients of a Proper Orthogonal Decomposition (POD) were defined as goals-outputs for this non-linear mapping. The coefficients time-series were predicted and the instantaneous velocity fields were reconstructed with satisfying accuracy with a Focused Time-Delay Neural Network (FTDNN). Using a time-delay appears like a crucial choice to ensure an accurate prediction of the dynamics of the BFS flow. A shallow FDTNN is sufficient to obtain good accuracy with low computational time. The influence of the choices of inputs-sensors, the size of the training data-set, the number of neurons in the hidden layer as well as the sensor delay on the accuracy of the predicted flow are discussed for this experimental fluid system.

Culture of cell spheroids in acoustic levitation

HAL (Le Centre pour la Communication Scientifique Directe), Jun 27, 2022

Frequency lock closed-loop control of a separated flow using visual feedback

arXiv (Cornell University), Nov 4, 2013

In this study, a simple model based closed-loop algorithm is used to control the separated flow d... more In this study, a simple model based closed-loop algorithm is used to control the separated flow downstream a backward-facing step. It has been shown in previous studies that the recirculation bubble can be minimized when exciting the shear layer at its natural Kelvin-Helmholtz instability frequency. In this experiment, the natural shedding frequency is identified through real-time analysis of 2D velocity fields. Actuation (pulsed jet) is then locked on this frequency. If flow characteristics stray too far from a set point, shedding frequency is updated and actuation changed. The present work demonstrates the efficacy and robustness of this approach in reducing recirculation while Reynolds number is randomly varied between 1400 and 2800.

Bulk acoustic waves-based system for a rapid and high throughput cell washing

HAL (Le Centre pour la Communication Scientifique Directe), Oct 19, 2022

Sensitivity of a backward facing step flow to the modification of the upstream boundary layer using LES simulations

HAL (Le Centre pour la Communication Scientifique Directe), Sep 19, 2006

International audienc

System identification using Neural Networks applied to experimental noise-amplifier flows characterized by real-time optical flow velocimetry

HAL (Le Centre pour la Communication Scientifique Directe), Sep 3, 2019

Cluster structuration of particle mixture in multi-node acoustic levitation with optical exclusion

HAL (Le Centre pour la Communication Scientifique Directe), Aug 26, 2020

Acoustic reconcentration or separation of cells

HAL (Le Centre pour la Communication Scientifique Directe), Sep 27, 2020

Fabrication of 2D monolayers and 3D spheroids of cells in acoustic levitation

HAL (Le Centre pour la Communication Scientifique Directe), Sep 27, 2020