Suropriya Saha

Max Planck Institute for Dynamics and Self-Organization

A common feature of biological self-organization is how active agents communicate with each other or their environment via chemical signaling. Such communications, mediated by self-generated chemical gradients, have consequences for both individual motility strategies and collective migration patterns. Here, in a purely physicochemical system, we u...

Protein condensates are complex fluids that can change their material properties with time. However, an appropriate rheological description of these fluids remains missing. We characterize the time-dependent material properties of in vitro protein condensates using laser tweezer–based active and microbead-based passive rheology. For different prote...

The constituent elements of active matter in nature often communicate with their counterparts or the environment by chemical signaling which is central to many biological processes. Examples range from bacteria or sperm that bias their motion in response to an external chemical gradient, to collective cell migration in response to a self-generated...

Pair interactions between active particles need not follow Newton’s third law. In this work, we propose a continuum model of pattern formation due to nonreciprocal interaction between multiple species of scalar active matter. The classical Cahn-Hilliard model is minimally modified by supplementing the equilibrium Ginzburg-Landau dynamics with parti...

Pair interactions between active particles need not follow Newton's third law. In this work we propose a continuum model of pattern formation due to non-reciprocal interaction between multiple species of scalar active matter. The classical Cahn-Hilliard model is minimally modified by supplementing the equilibrium Landau-Ginzburg dynamics with parti...

We study theoretically an active colloid whose polar axis of self-propulsion rotates to point parallel (antiparallel) to an imposed chemical gradient. We show that the coupling of this ‘chemotactic’ (‘antichemotactic’) response to phoretic translational motion yields remarkable two-particle dynamics reflecting the non-central and non-reciprocal cha...

An interacting pair of chemotactic (anti-chemotactic) active colloids, that can rotate their axes of self-propulsion to align {parallel (anti-parallel)} to a chemical gradient, shows dynamical behaviour that varies from bound states to scattering. The underlying two-body interactions are purely dynamical, non-central, non-reciprocal, and controlled...

The creation of synthetic systems that emulate the defining properties of living matter, such as motility, gradient-sensing, signaling, and replication, is a grand challenge of biomimetics. Such imitations of life crucially contain active components that transform chemical energy into directed motion. These artificial realizations of motility point...

A colloid supported against gravitational settling by means of an imposed electric field behaves, on average, as if it is at equilibrium in a confining potential [T. M. Squires, J. Fluid Mech. 443, 403 (2001)]. We show, however, that the effective Langevin equation for the colloid contains a nonequilibrium noise source, proportional to the field, a...

The creation of synthetic systems that emulate the defining properties of living matter, such as motility, gradient-sensing, signalling and replication, is a grand challenge of biomimetics. Such imitations of life crucially contain active components that transform chemical energy into directed motion. These artificial realizations of motility point...

An artificial phoretic swimmer in a uniform bath of reactant propels itself in a direction dictated by the polarity of the enzymatic and mobility patterning on its surface. We have have shown that a polar active particle of this type can also orient itself along an imposed gradient of reactant concentration. This amounts to a theoretical demonstrat...