Droplet motion driven by tensotaxis

It is well documented that cells can migrate in response to gradients in stiffness (durotaxis) and gradients in strain (tensotaxis) in the underlying substrate. Understanding the potential physical mechanisms at play during this motion has motivated recent efforts to unravel the role of surface tension in the interaction between droplets and soft solids. Here, we present a multiphysics phase-field model of fluid–solid interaction, which allows us to isolate the effects of strain gradients—something difficult to achieve in experiments. Our high-fidelity numerical simulations in two and three dimensions elucidate the physics of tensotaxis, and show how localized forces in a soft substrate can be used to move and merge droplets deposited on it.