Cellular Flow Architecture Exposes the Hidden Mechanics of Biological Matter

TL;DR

This paper reveals that Lagrangian coherent structures in cellular flows act as hidden skeletons that predict stress distribution and cell extrusion sites, providing new insights into the mechanics of biological development.

Contribution

It demonstrates that flow skeletons based on LCSs precede and influence stress reorganization in cellular tissues, linking microscopic motion to biomechanics.

Findings

LCSs mark stress hotspots exceeding tenfold.

Flow skeletons correlate with cell packing heterogeneities.

Attractors predict future cell extrusion sites.

Abstract

Understanding how biomechanical reorganization governs key biological processes, such as morphogenesis and development, requires predictive insights into stress distributions and cellular behavior. While traditional approaches focused on cell motion as a response to stress, we demonstrate that Lagrangian coherent structures (LCSs) -- robust attractors and repellers in cellular flows -- precede and drive long-term intercellular stress reorganization, physically governed by the mechanical properties of intercellular junctions. We show that this hidden flow skeleton correlates strongly with biomechanical metrics, bridging microscopic cell motion with mesoscopic biomechanics. Specifically, attractors and repellers mark hotspots of compressive and tensile stress enrichment (exceeding tenfold), alongside heterogeneities in cell packing. Notably, these connections remain robust across varying strengths of cell-cell and cell-substrate force transmission. Finally, by linking the attracting regions in the flow skeleton to future cell extrusion spots, we establish a direct link between cell motion and biologically significant outcomes. Together, these findings establish a framework for using cell motion to independently infer biomechanical metrics and bridge the scale mismatch between cell motion and biomechanics, potentially offering a new route to interpret mechanosensitive biological processes directly from cell trajectories.