The ability to program collective cell migration can allow us to control critical multicellular processes in development, regenerative medicine, and invasive disease. However, while various technologies exist to make individual cells migrate, translating these tools to control myriad, collectively interacting cells within a single tissue poses many challenges. For instance, do cells within the same tissue interpret a global migration ‘command’ differently based on where they are in the tissue? Similarly, since no stimulus is permanent, what are the long-term effects of transient commands on collective cell dynamics? We investigate these questions by bioelectrically programming large epithelial tissues to globally migrate ‘rightward’ via electrotaxis. Tissues clearly developed distinct rear, middle, side, and front responses to a single global migration stimulus. Furthermore, at no point poststimulation did tissues return to their prestimulation behavior, instead equilibrating to a 3rd, new migratory state. These unique dynamics suggested that programmed migration resets tissue mechanical state, which was confirmed by transient chemical disruption of cell–cell junctions, analysis of strain wave propagation patterns, and quantification of cellular crowd dynamics. Overall, this work demonstrates how externally driving the collective migration of a tissue can reprogram baseline cell–cell interactions and collective dynamics, even well beyond the end of the global migratory cue, and emphasizes the importance of considering the supracellular context of tissues and other collectives when attempting to program crowd behaviors.

The ability to program collective cell migration can allow us to control critical multicellular processes in development, regenerative medicine, and invasive disease. However, while various technologies exist to make individual cells migrate, translating these tools to control myriad, collectively interacting cells within a single tissue poses many challenges. For instance, do cells within the same tissue interpret a global migration 'command' differently based on where they are in the tissue? Similarly, since no stimulus is permanent, what are the long-term effects of transient commands on collective cell dynamics? We investigate these questions by bioelectrically programming large epithelial tissues to globally migrate 'rightward' via electrotaxis. Tissues clearly developed distinct rear, middle, side, and front responses to a single global migration stimulus. Furthermore, at no point post-stimulation did tissues return to their pre-stimulation behavior, instead equilibrating to a third, new migratory state. These unique dynamics suggested that programmed migration resets tissue mechanical state, which was confirmed by transient chemical disruption of cell-cell junctions, analysis of strain wave propagation patterns, and quantification of cellular crowd dynamics. Overall, this work demonstrates how externally driving the collective migration of a tissue can reprogram baseline cell-cell interactions and collective dynamics, even well beyond the end of the global migratory cue, and emphasizes the importance of considering the supracellular context of tissues and other collectives when attempting to program crowd behaviors.

Epithelial tissues sheath many organs, separating 'outside' from 'inside' and exquisitely regulating ion and water transport via electromechanical pumping to maintain homeostatic balance and tissue hydrostatic pressure. While it is becoming increasingly clear that the ionic microenvironment and external electric stimuli can affect epithelial function and behavior, the coupling between electrical perturbation and tissue form remain unclear. We investigated this by combining electrical stimulation with three-dimensional epithelial tissues with hollow 'lumens'--both kidney cysts and complex intestinal stem cell organoids. Our core finding is that physiological strength electrical stimulation of order 1-3 V/cm (with both direct and alternating currents) can drive powerful and rapid inflation of hollow tissues through a process we call 'electro-inflation', inducing a nearly threefold increase in tissue volume and striking asymmetries in tissue form. Electro-inflation is primarily driven by activation of the CFTR ion channel pumping chloride into the tissue, causing water to osmotically flow. This influx generates hydrostatic pressure, and inflation results from a competition between this pressure and cell cytoskeletal tension. We validated these interpretations with computational models connecting ion dynamics in the Diffuse Double Layer around tissues to tissue mechanics. Electro-inflation is a unique biophysical process to study and control complex tissue function.

Epithelial tissues sheath many organs, separating ‘outside’ from ‘inside’ and exquisitely regulating ion and water transport via electromechanical pumping to maintain homeostatic balance and tissue hydrostatic pressure. While it is becoming increasingly clear that the ionic microenvironment and external electric stimuli can affect epithelial function and behavior, the coupling between electrical perturbation and tissue form remain unclear. We investigated this by combining electrical stimulation with three-dimensional epithelial tissues with hollow ‘lumens’—both kidney cysts and complex intestinal stem cell organoids. Our core finding is that physiological strength electrical stimulation of order 1-3 V/cm (with both direct and alternating currents) can drive powerful and rapid inflation of hollow tissues through a process we call ‘electro-inflation’, inducing a nearly threefold increase in tissue volume and striking asymmetries in tissue form. Electro-inflation is primarily driven by activation of the CFTR ion channel pumping chloride into the tissue, causing water to osmotically flow. This influx generates hydrostatic pressure, and inflation results from a competition between this pressure and cell cytoskeletal tension. We validated these interpretations with computational models connecting ion dynamics in the Diffuse Double Layer around tissues to tissue mechanics. Electro-inflation is a unique biophysical process to study and control complex tissue function.

Cells attach to the world around them in two ways, cell:extracellular matrix adhesion and cell:cell adhesion and conventional biomaterials are made to resemble the matrix to encourage integrin based cell adhesion. However, interest is growing for cell mimetic interfaces that mimic cell cell interactions using cadherin proteins, as this offers a new way to program cell behavior and design synthetic implants and objects that can integrate directly into living tissues. Here, we explore how these cadherin based materials affect collective cell behaviors, focusing specifically on collective migration and cell cycle regulation in mm scale epithelia. We built culture substrates where half of the culture area was functionalized with matrix proteins and the contiguous half was functionalized with E-cadherin proteins, and we grew large epithelia across this Janus interface. Parts of the tissues in contact with the matrix side of the Janus interface exhibited normal collective dynamics, but an abrupt shift in behaviors happened immediately across the Janus boundary onto the E-cadherin side, where cells formed hybrid E-cadherin junctions with the substrate, migration effectively froze in place, and cell cycling significantly decreased. E-cadherin materials suppressed long-range mechanical correlations in the tissue and mechanical information reflected off the substrate interface. These effects could not be explained by conventional density, shape index, or contact inhibition explanations. E-cadherin surfaces nearly doubled the length of the G0/G1 phase of the cell cycle, which we ultimately connected to the exclusion of matrix focal adhesions induced by the E-cadherin culture surface.