409 citations · 2.2k across the 36 of their papers we have counts for
38 papers
Migrating cell clusters as active droplets with asymmetric shape and contact angles
Hanno I. Hennighausen, Jaime A. Espina, Elias H. Barriga +1
During embryonic development and cancer progression, clusters of cells migrate collectively following external cues. Such migrating cell clusters have been modeled as active drople…
Active wetting transition in cell aggregates
MJ Franco-Oñate, Hanno I. Hennighausen, Ricard Alert
During many biological processes, cell aggregates spread on substrates in a process of active wetting. The existing models of tissue spreading, however, do not explicitly capture t…
Quantum motility-induced phase separation
Laurin Brunner, Ricard Alert, Reyhaneh Khasseh +1
Motility-induced phase separation (MIPS) describes a central clustering phenomenon in active matter systems where particles spontaneously separate into dense and dilute phases even…
Bistability of cellular traction on strain-stiffening substrates
Irina Pi-Jaumà, Jaume Casademunt, Ricard Alert
To migrate, cells exert traction forces on the extracellular matrix (ECM) -- a biopolymer network that often exhibits nonlinear strain-stiffening elasticity. Cellular tractions can…
Nonequilibrium noise emerging from broken detailed balance in active gels
Ashot Matevosyan, Frank Jülicher, Ricard Alert
In thermodynamic equilibrium, the fluctuation-dissipation theorem links thermal fluctuations and dissipation. Biological systems, however, are driven out of equilibrium by internal…
Modes of Mechanical Guidance of Adhesion-Independent Cell Migration
Hanna Luise Gertack, Peter A. E. Hampshire, Claudia Wohlgemuth +2
Adhesion-independent migration is a prominent mode of cell motility in confined environments, yet the physical principles that guide such movement remain incompletely understood. W…
Lattice-dependent orientational order in active crystals
Till Welker, Ricard Alert
Via mechanisms not accessible at equilibrium, self-propelled particles can form phases with positional order, such as crystals, and with orientational order, such as polar flocks.…
Hamiltonian description of nonreciprocal interactions
Yu-Bo Shi, Roderich Moessner, Ricard Alert +1
In a vast class of systems, which includes members as diverse as sedimenting particles and bird flocks, interactions do not stem from a potential, and are in general nonreciprocal.…
Discontinuous transition to active nematic turbulence
Malcolm Hillebrand, Ricard Alert
Active fluids exhibit chaotic flows at low Reynolds number known as active turbulence. Whereas the statistical properties of the chaotic flows are increasingly well understood, the…
Active screws: Emergent active chiral nematics of spinning self-propelled rods
Debarghya Banerjee, Lauritz Hahn, Ricard Alert
Several types of active agents self-propel by spinning around their propulsion axis, thus behaving as active screws. Examples include cytoskeletal filaments in gliding assays, magn…
Buckling by disordered growth
Rahul G. Ramachandran, Ricard Alert, Pierre A. Haas
Buckling instabilities driven by tissue growth underpin key developmental events such as the folding of the brain. Tissue growth is disordered due to cell-to-cell variability, but…
Dynamical arrest in active nematic turbulence
Ido Lavi, Ricard Alert, Jean-François Joanny +1
Active fluids display spontaneous turbulent-like flows known as active turbulence. Recent work revealed that these flows have universal features, independent of the material proper…
Nonlinear spontaneous flow instability in active nematics
Ido Lavi, Ricard Alert, Jean-François Joanny +1
Active nematics exhibit spontaneous flows through a well-known linear instability of the uniformly-aligned quiescent state. Here we show that even a linearly stable uniform state c…
Flocking by Turning Away
Suchismita Das, Matteo Ciarchi, Ziqi Zhou +3
Flocking, as paradigmatically exemplified by birds, is the coherent collective motion of active agents. As originally conceived, flocking emerges through alignment interactions bet…
Local polar order controls mechanical stress and triggers layer formation in developing Myxococcus xanthus colonies
Endao Han, Chenyi Fei, Ricard Alert +4
Colonies of the social bacterium Myxococcus xanthus go through a morphological transition from a thin colony of cells to three-dimensional droplet-like fruiting bodies as a strateg…
Fingering Instability of Active Nematic Droplets
Ricard Alert
From the mitotic spindle up to tissues and biofilms, many biological systems behave as active droplets, which often break symmetry and change shape spontaneously. Here, I show that…
Curvature induces active velocity waves in rotating multicellular spheroids
Tom Brandstätter, David B. Brückner, Yu Long Han +3
The multicellular organization of diverse systems, such as embryos, intestines and tumours, relies on the coordinated migration of cells in 3D curved environments. In these setting…
Collective durotaxis of cohesive cell clusters on a stiffness gradient
Irina Pi-Jaumà, Ricard Alert, Jaume Casademunt
Many types of motile cells perform durotaxis, namely, directed migration following gradients of substrate stiffness. Recent experiments have revealed that cell monolayers can migra…
Cellular Sensing Governs the Stability of Chemotactic Fronts
Ricard Alert, Alejandro Martínez-Calvo, Sujit S. Datta
In contexts ranging from embryonic development to bacterial ecology, cell populations migrate chemotactically along self-generated chemical gradients, often forming a propagating f…
Living cells on the move
Ricard Alert, Xavier Trepat
Spectacular collective phenomena such as jamming, turbulence, wetting, and waves emerge when living cells migrate in groups.
Active Turbulence
Ricard Alert, Jaume Casademunt, Jean-François Joanny
Active fluids exhibit spontaneous flows with complex spatiotemporal structure, which have been observed in bacterial suspensions, sperm cells, cytoskeletal suspensions, self-propel…
Scaling regimes of active turbulence with external dissipation
Berta Martínez-Prat, Ricard Alert, Fanlong Meng +5
Active fluids exhibit complex turbulent-like flows at low Reynolds number. Recent work predicted that 2d active nematic turbulence follows universal scaling laws. However, experime…
Chemotactic smoothing of collective migration
Tapomoy Bhattacharjee, Daniel B. Amchin, Ricard Alert +2
Collective migration -- the directed, coordinated motion of many self-propelled agents -- is a fascinating emergent behavior exhibited by active matter that has key functional impl…
Active phase separation by turning toward regions of higher density
Jie Zhang, Ricard Alert, Jing Yan +2
Studies of active matter, from molecular assemblies to animal groups, have revealed two broad classes of behavior: a tendency to align yields orientational order and collective mot…