In this research, we show that the active droplet microswimmer gets attracted to, trapped by and
eventually escapes from the corner of the air-water and oil-water menisci. Using Lattice Boltzmann simulations and a hydrodynamic model, we show that the force dipole strength guides the swimmer to orient towards the corner tip and traps it there. But it is the source dipole strength that ultimately helps the swimmer escape. For more, visit arXiv:2604.19552.
Here, we present a numerical framework for simulating isotropic autophoretic microswimmers whose propulsion arises solely from self-generated chemical gradients, without any built-in geometric or chemical anisotropy.
The method employs a high-accuracy pseudospectral solver that resolves the coupled advection–diffusion–Navier-Stokes equations on a fixed Eulerian grid.
The Preprint of the work can be found at:
https://doi.org/10.48550/arXiv.2512.21756
Our recent study demonstrates that a self-propelling droplet microswimmer drastically changes its behavior in soft microchannels. Unlike the unidirectional swimming observed in rigid microchannels, the microswimmers in soft microchannels exhibit a run-and-tumble-like motion, marked by sudden reorientations and velocity variations. Through fluorescence microscopy and numerical modeling, we reveal that this new motility arises from the interplay between elastohydrodynamic effects of the soft microchannel walls and the chemohydrodynamic forces driving the self-propulsion. The Preprint of the work can be found at: doi.org/10.48550/arXiv.2508.04443
We recently described how active droplets adapt their shape and flow field to swim through progressively tighter microchannels, transforming from spherical to capsule-like shapes in our new publication Physical Review Fluids, 10, 044202, 2025. This shape adaptation changes their hydrodynamic signature from symmetric quadrupolar to asymmetric flows, where thin-film lubrication and Marangoni stresses drive propulsion with a reduced velocity.
Ranabir Dey and his previous group at Max Planck Institute of Dynamics and Self-organization in Goettingen (Germany) studied the electrotaxis behaviour of active droplets in a microconfinement in his new publication “Electrotaxis of Self-Propelling Artificial Swimmers in Microchannels”, Phys. Rev. Lett. 133, 158301, 2024.
Ranabir Dey, in collaboration with Prof. Sumesh Thampi (IIT Madras), studied how confinement affects the 3D trajectories of microswimmers in square and rectangular channels in his publication Physical Review Fluids, 9, 083302 (2024). Using lattice-Boltzmann simulations and far-field hydrodynamic theory, the study shows that pushers typically follow helical paths, pullers exhibit sliding, while neutral swimmers display complex, initial-condition-dependent trajectories.
Ranabir Dey and his previous group at Max Planck Institute of Dynamics and Self-organization in Goettingen (Germany) describe how artificial microswimmers swim upstream in an oscillatory trajectory against a pressure driven flow in strong confinements in their new publication ‘Oscillatory rheotaxis of artificial swimmers in microchannels’ in Nature Communications, 13, 2952, 2022
Ranabir Dey’s research on how self-propelling droplet microswimmers adapt to increasing viscosity in their surrounding by exhibiting a non-intuitive bimodal motility has appeared in Physical Review X, 11 (1), 011043, 2021
