Cells are masters at working together and coordinating their efforts. Cells are able to communicate with one another, apply pressure to one another, and eliminate cells from the tissue that are not contributing to the overall health of the collective through these processes. A procedure known as cell extrusion is started when it is time to dispose of a cell by the collective group. Expulsion of cells may occur for a variety of reasons, including the fact that they may be malignant, that they may be elderly, or that they may simply be crowding out other cells. To keep their health and integrity intact, tissues require an essential process known as extrusion.
A publication titled “Mechanical Basis and Topological Routes to Cell Elimination” that was published in the journal eLife details both the model and the conclusions. Guruswami Ravichandran, who is the John E. Goode, Jr., Professor of Aerospace and Mechanical Engineering; José Andrade, who is the George W. Housner Professor of Civil and Mechanical Engineering; and the Niels Bohr Institute in Copenhagen, Denmark, worked together on the project at their respective laboratories.
A phase of matter that can be thought of as existing between a solid and a liquid is called a liquid crystal. The molecules that make up the liquid crystal substance are able to move around freely, similar to ordinary liquids, despite the fact that the substance has the resistance to deformation of a solid. The discipline of condensed matter physics has traditionally been the one that has been responsible for the investigation of liquid crystals; nevertheless, in the past six years, this field has been utilised to characterise the behaviour of live cells.
“The most exciting part of this study is that we are just scratching the surface of combining these fields,” says Siavash Monfared, the study’s first author and a former postdoctoral scholar at Caltech. “The most exciting part of this study is that we are just scratching the surface of combining these fields.” The fact that biological systems are dynamic and not in a state of equilibrium is one of the most difficult aspects of biology, in contrast to the fact that physics and mechanics are frequently centred on the concept of thermodynamic equilibrium. The study of active matter holds a lot of potential for better understanding biological processes through the use of physics and other physical factors.
In this latest body of work, the group modelled a single layer of cells by making use of the fundamentals of liquid crystal physics. The cells are modelled as active and flexible spherical droplets. They are packed in closely together in the same manner that real cells form a tissue, and they are positioned atop a substrate. The researchers were then able to modify a parameter known as adhesion, which is a measure of how strongly the cells attached to one another or the substrate, and examine how the changes in adhesion influenced the behaviour of the extrusion process.