|Posted on July 7, 2015 at 6:45 PM|
Understanding the dynamics and mode of function of tissues in key organs, such as the heart, lungs and blood vessels, is very important for a number of medical fields, including cancer research and regenerative medicine. Epithelial cell sheets, a 2-dimensional structure composed of living cells, is a popular model material that researchers use to investigate the dynamics and functioning of tissues. These epithelial cell sheets are used with an extracelluar matrix, often made of hydrogel or collagen, whose properties can be controlled to study cell-cell interactions or cell-matrix interactions in different environments.
In a recent Nature Materials publication, Dr. Laura Casares, a postdoctoral researcher in the Trepat Research Group at the Institute of Bioengineering of Catalonia, Spain, demonstrated an interesting observation of cell-sheet dynamics. Dr. Casares and her colleagues were interested in studying the cracking of cell sheets induced from stress in the extracellular matrix, polyacrylamide hydrogel. Stressing porous material can lead to cracking, as can be seen in dry soil or concrete roads for instance. Surprisingly, Dr. Casares observed that the cell-sheet would crack when the stress on the hydrogel was released - rather than when the hydrogel was under large stress. In the article, the researchers explained that this is due the hydraulic pressure that builds up in the hydrogel when the stress is released, also known as the poroelastic effect. When hydrogel is under stress, it is in a dry state; but when the stress is released, the gel swells back and builds pressure, which causes the cell sheet to crack. The researchers also reported the self-healing of the cell-sheet after hydraulic fracturing. This study provides important information in understanding cell-matrix interactions, and could be used further to gain insights in mechanical interaction of cells across different structures and functionality.
- Written by Eugene Choi, Edited by Paulette Clancy
(Photo credit: Casares: Provided by and used with permission from Laura Casares, Figure: Casares, Laura; Vincent, Romaric; Zalvidea, Dobryna; Campillo, Noelia; Navajas, Daniel; Arroyo, Marino and Trepat, Xavier. Nature Materials, 14, 343-351 (2015) doi: 10_1038/nmat4206).