Synopsis

Soft Tissues with Sharp Boundaries

Physics 11, s13
A model for cellular populations incorporates neighbor-specific interactions to explain sharp boundaries observed around tissues.
D. Sussman et al., Phys. Rev. Lett. (2018)

Cells in a developing embryo tend to segregate by cell type, forming tissues with distinct boundaries. Explanations of this behavior often rely on an analogy to immiscible fluids, like oil and water, which naturally separate because of intermolecular forces. However, cells are not passive like molecules; they actively respond to their environment, or “neighbors.” New simulations explore neighbor-specific interactions that may explain the sharp tissue boundaries that characterize embryo development and some forms of tumor growth.

A common model system for investigating cellular arrangements is a two-dimensional layer of cells in which the cells fill the space by pushing into each other. From above, the cells resemble a patchwork of straight-sided polygons whose shapes depend on cell stiffness and other cellular forces. This so-called vertex model has successively reproduced biological processes such as embryonic development and tumor metastasis.

Daniel Sussman and colleagues from Syracuse University in New York explored a vertex model with two types of cells. Specifically, they simulated a tissue of A cells surrounded by a population of B cells. The team assumed that the interfacial tension along the border between A and B cells is different from that between cells of the same type. This neighbor-specific interaction created an unexpected discrepancy between two types of simulated “measurements” of the surface tension at the tissue boundary. The team obtained a lower tension value for measurements made by virtually squeezing the tissue between two plates than for measurements made by recording small-scale fluctuations, or roughness, along the tissue boundary. According to the researchers, this result suggests that while tissues and other biological systems may be soft and squishy overall, they have sharp, seemingly hard, boundaries.

This research is published in Physical Review Letters.

–Michael Schirber

Michael Schirber is a Corresponding Editor for Physics based in Lyon, France.


Subject Areas

Biological Physics

Related Articles

Solving a Puzzle in Brain Development
Biological Physics

Solving a Puzzle in Brain Development

Scientists may have answered a longstanding question in biophysics: how the brain learns to recognize features in images before a newborn even opens its eyes. Read More »

Turbulence-Surfing Plankton Can Double Their Speed
Fluid Dynamics

Turbulence-Surfing Plankton Can Double Their Speed

Simulations indicate that plankton can gain quicker access to food by riding ascending turbulent ocean currents. Read More »

A Tiny Photonic Nose Captures Odor Fingerprints
Biological Physics

A Tiny Photonic Nose Captures Odor Fingerprints

A bio-inspired detector the size of a US penny can identify the unique odor profiles of different gases, something that could help in detecting food freshness and product counterfeits and in designing new cosmetics. Read More »

More Articles