Squishy Physics

Next seminar: Wednesday April 17th 2019 in Pierce Hall 209 at 6:00 PM

Fluidity and jamming in epithelial tissues

Max Bi

Northeastern University

Abstract: Cells must move through tissues in many important biological processes, including embryonic development, cancer metastasis, and wound healing. Often these tissues are dense and a cell's motion is strongly constrained by its neighbors, leading to glassy dynamics. Although there is a density-driven glass transition in particle-based models for active matter, these cannot explain liquid-to-solid transitions in confluent tissues, where there are no gaps between cells and the packing fraction remains fixed and equal to unity. I will demonstrate the existence of a new type of rigidity transition that occurs in confluent tissue monolayers at constant density. The onset of rigidity is governed by a model parameter that encodes single-cell properties such as cell-cell adhesion and cortical tension. I will also introduce a new model that simultaneously captures polarized cell motility and multicellular interactions in a confluent tissue and identify a glassy transition line that originates at the critical point of the rigidity transition. This work suggests an experimentally accessible structural order parameter that specifies the entire transition surface separating fluid tissues and solid tissues. Finally, I will discuss recent work using a culture of human lung epithelial tissue to compare a newly discovered mode of fluidization of jammed cells – the unjamming transition (UJT) – with the canonical epithelial-to-mesenchymal transition (EMT).


Squishy Physics & Pizza Seminar Series

When: Wednesday Evenings - Pizza served at 5:55 PM, talks start at 6 pm till...

Where: Room 209, Pierce Hall, 29 Oxford St, on the Harvard Campus. Directions and parking instructions are here.

What: These talks are informal, with emphasis on new results and ideas, rather than polished presentations. The Squishy audience members typically include soft matter scientists, physicists, engineers, chemists, and biologists.  The goal is to stimulate discussion with the audience.  Talks are typically about 45 minutes long, with lots of questions along the way.

Pizza: Only the finest! 

How to join the weekly Squishy Physics mailing list: please visit the Signup Page.

Directions: Where: Squishy Physics talks are held in Pierce Hall room 301, 29 Oxford Street, Cambridge, MA. See Harvard Campus map here.

Parking: Metered parking is available on Oxford Street.  Speakers, please contact Matthew Zahnzinger to obtain a parking permit.  

Squishy Physics is sponsored by the Cabot Corporation, Dean Cherry Murray and the Weitz Research Group.

If you have comments or suggestions or would like to give a talk, please contact Joerg Werner, Stefano Aime, or Perry Ellis.

Here is the upcoming schedule