Single-cell motion of magnetotactic bacteria in microfluidic confinement: interplay between surface interaction and magnetic torque

Codutti, Agnese; Charsooghi, Mohammad A.; Cerdá-Doñate, Elisa; Hm, Taïeb; Robinson, Tom; Faivre, Damien; Klumpp, Stefan

doi:10.1101/2021.03.27.437322

Cited by 3 publications

(3 citation statements)

References 61 publications

(90 reference statements)

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“…While we observed that the geometry of the confinement affects structure formation to a greater extent, a recent study has demonstrated that reorienting torques at walls in numerical simulations are crucial to faithfully reproduce experimental observations of magnetotactic bacteria in circular traps [115]. We note that the parameters chosen in that study are similar to the ones presented in this thesis.…”

Section: Discussionsupporting

confidence: 63%

“…Typically, active particles are confined by different geometries during experiments like microtraps (circular) [115] or channels and chambers in microfluidic devices (squared). To investigate the effect of confinement on structure formation in small systems, we varied both the geometry and the type of interactions between the particle and the confining walls in this section.…”

Section: Influence Of Confinement On Structure Formationmentioning

confidence: 99%

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Structure Formation and Collective Behavior of Dipolar Active Particles

Telezki¹

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Dipolar active particles describe a class of self-propelled, biological or artificial particles. These particles are equipped with an internal, typically magnetic, dipole moment. The combination of dipolar particle-particle interactions and activity leads to emerging complex collective behavior in systems of such particles.In this thesis, we use Brownian dynamics simulations to explore and characterize the plethora of structural dynamics and pattern formation in systems of dipolar active particles. This study can be divided into four parts. First, we focus on structure formation in small systems. Here, we mainly observe chain and ring formation and characterize how activity and spatial confinement affects these structures. Second, we move to large systems of dipolar active particles, classify the collective patterns we observed and summarize our results in diagrams of states. We show that activity plays a crucial role in the emergent collective behavior in systems of dipolar active particles. Third, we investigate the effect a constant homogeneous external magnetic field has on collective dynamics of the system. We observe that band formation is suppressed by strong external magnetic fields and columnar structures form. In addition, we notice a previously not characterized transient state of oscillating chains of active dipolar particles. We hypothesize that these oscillations are caused by buckling instabilities. Finally, we introduce a time dependent external magnetic field and study the dynamics of structure formation driven by that field.This thesis demonstrates how dipolar interactions, external magnetic fields, or confinement, can further add to the rich complex collective behavior in systems of active particles.

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Section: Discussionsupporting

confidence: 63%

Section: Influence Of Confinement On Structure Formationmentioning

confidence: 99%

Structure Formation and Collective Behavior of Dipolar Active Particles

Telezki¹

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“…This single-cell heterogeneity may be suppressed if only population averages are considered. However, long-term tracking of the same individual was not possible until very recently [11,7,12].…”

Section: Introductionmentioning

confidence: 99%

Phenotyping single-cell motility in microfluidic confinement

Bentley

Schlogelhofer

Anagnostidis

et al. 2022

eLife

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The movement trajectories of organisms serve as dynamic read-outs of their behaviour and physiology. For microorganisms this can be difficult to resolve due to their small size and fast movement. Here, we devise a novel droplet microfluidics assay to encapsulate single micron-sized algae inside closed arenas, enabling ultralong high-speed tracking of the same cell. Comparing two model species - Chlamydomonas reinhardtii (freshwater, 2 cilia), and Pyramimonas octopus (marine, 8 cilia), we detail their highly-stereotyped yet contrasting swimming behaviours and environmental interactions. By measuring the rates and probabilities with which cells transition between a trio of motility states (smooth-forward swimming, quiescence, tumbling or excitable backward swimming), we reconstruct the control network that underlies this gait switching dynamics. A simplified model of cell-roaming in circular confinement reproduces the observed long-term behaviours and spatial fluxes, including novel boundary circulation behaviour. Finally, we establish an assay in which pairs of droplets are fused on demand, one containing a trapped cell with another containing a chemical that perturbs cellular excitability, to reveal how aneural microorganisms adapt their locomotor patterns in real-time.

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Phenotyping single-cell motility in microfluidic confinement

Bentley

Anagnostidis

Schlogelhofer

et al. 2021

Preprint

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At all scales, the movement patterns of organisms serve as dynamic read-outs of their behaviour and physiology. We devised a novel droplet microfluidics assay to encapsulate single algal microswimmers inside closed arenas, and comprehensively studied their roaming behaviour subject to a large number of environmental stimuli. We compared two model species, Chlamydomonas reinhardtii (freshwater alga, 2 cilia), and Pyramimonas octopus (marine alga, 8 cilia), and detailed their highly-stereotyped behaviours and the emergence of a trio of macroscopic swimming states (smooth-forward, quiescent, tumbling or excitable backward). Harnessing ultralong timeseries statistics, we reconstructed the species-dependent reaction network that underlies the choice of locomotor behaviour in these aneural organisms, and discovered the presence of macroscopic non-equilibrium probability fluxes in these active systems. We also revealed for the first time how microswimmer motility changes instantaneously when a chemical is added to their microhabitat, by inducing deterministic fusion between paired droplets - one containing a trapped cell, and the other, a pharmacological agent that perturbs cellular excitability. By coupling single-cell entrapment with unprecedented tracking resolution, speed and duration, our approach offers unique and potent opportunities for diagnostics, drug-screening, and for querying the genetic basis of micro-organismal behaviour.

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Single-cell motion of magnetotactic bacteria in microfluidic confinement: interplay between surface interaction and magnetic torque

Cited by 3 publications

References 61 publications

Structure Formation and Collective Behavior of Dipolar Active Particles

Structure Formation and Collective Behavior of Dipolar Active Particles

Phenotyping single-cell motility in microfluidic confinement

Phenotyping single-cell motility in microfluidic confinement

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