Biology subjects

Benoit-Gonin, X.

Publications and source records attributed to Benoit-Gonin, X..

3 recordsLinked to original sources

bioRxiv2025

Low-Power Acoustic Trapping and Illumination Optimization of Cyanobacteria by Acoustic Layering in Photobioreactors

Space missions require sustainable life support systems capable of producing oxygen and biomass under microgravity. We report the use of acoustic levitation to trap and manipulate the filamentous cyanobacterium Limnospira indica PCC 8005 during parabolic flights. Within a millimeter-scale fluidic chamber, this helical microorganism rapidly assembles into thin layers under a standing ultrasonic wave. Stable trapping in microgravity requires substantially less acoustic power (0.42 mW) than on Earth (1.4 mW), highlighting the potential for energy-efficient bioprocessing in space. Monte Carlo simulations and light attenuation modelling show that layered structuring enhances light penetration, potentially overcoming the "compensation point" limitation in bulk cultures. These findings open new perspectives for photobioreactors using acoustic manipulation to boost photosynthetic efficiency and reduce energy demands for oxygen and biomass production in space.

biophysics↗

bioRxiv2025

Medium-assisted tumbling controls bacteria exploration in a complex fluid

In nature, many fluids that harbor bacterial populations or protect against microbial contamination exhibit non-Newtonian rheology. To study the spatial exploration of E.coli bacteria, a model multi-flagellated microorganism, in such complex environments, we design a motility medium with tunable macroscopic rheology. By increasing the solid charge in soft carbomer grains, we transition from a Newtonian viscous suspension to a yield-stress fluid. Using a 3D Lagrangian tracking device, we collect many individual bacterial tracks and characterize changes in motility properties such as swimming speed, persistence times and diffusivity for both a wild-type and a smooth runner mutant, up to the formation of a motility barrier at higher carbomer concentrations. We show that the presence of local mechanical disorder and resistance to penetration essentially override the biologically driven run-and-tumble navigation process. This "medium-assisted" exploration scenario is characterized by directional switching and stop-and-go kinematics and is closely related to the flexibility of the flagellar bundle.

biophysics↗

bioRxiv2024

Microgravity stimulates network activity of 3D neuronal spheroids in an acoustic trap

Among biological models, cell culture constitutes an important paradigm that allows rapid examination of cell phenotype and behavior. While cell cultures are classically grown on a 2D substrate, the recent development of organoid technologies represents a paradigmatic shift in biological experimentation as they pave the way for the reconstruction of minimalist organs in 3D. Manipulating these 3D cell assemblies represents a considerable challenge. While there is growing interest in studying the behavior of cells and organs in the space environment, manipulating 3D cultures in microgravity remains a challenge. But with cellular research underway aboard the International Space Station (ISS), optimizing techniques for handling 3D cellular assemblies is essential. Here, in order to cultivate 3D models of spheroids in microgravity, we developed and used an acoustic bioreactor to trap levitating cellular organoids in a liquid cell culture medium. Indeed, in a Bulk Acoustic Wave (BAW) resonator, spherical objects, such as cells, can be maintained in an equilibrium position, inside a resonant cavity, away from the walls. In the acoustic levitation plane, gravity is counterbalanced by the acoustic radiation force (ARF) making it possible to maintain an object even in weightlessness. A dedicated setup was designed and built to perform live calcium imaging during parabolic flights. During a parabolic flight campaign, we were able to monitor the calcium activity of 3D neural networks trapped in an acoustic field during changes in gravity during different parabolas. Our results clearly indicate a change in calcium activity associated with variations in gravity.

biophysics↗