Supervisor: Francesca Serra
Project description
Many types of living cells are spontaneously elongated and align with their neighboring cells. In this, their behavior is similar to that of liquid crystals, complex fluids commonly found in displays. In cells this affects the patterns of cell migration and the cell-cell communication. In well-aligned cell layers (or in liquid crystals) one can define an average direction, described as a vector called the nematic director. However, there can be many situations where a uniform alignment of cells everywhere is impossible. In these scenarios the cells form “topological defects”, small regions where the order is disrupted and the cells’ orientation is not uniform. Topological defects are ubiquitous in physics, from superconductors to cosmic strings. There is increasing evidence that these defects play a key role also in the organization of cell layers and of tissues.
In my lab, we can impose distortions or defects by changing the shape of the substrates, for example by patterning small ridges that help guide the cells, or by . We want to ask the questions: what type of alignments do cells achieve when they walk on a substrate that has many curves and bumps? How are defects connected to the curvature of the substrate? How does surface treatment affect the behavior? These questions are fundamental both for physics and biology. In physics, because we study topological defects in dynamic out-of-equilibrium systems, and in biology because we use liquid crystals for a better understanding of cells' organization in tissues.
The project(s) will involve fabricating the patterned substrates starting from a template (PDMS soft lithography), growing cells on them, observing them with optical microscopy and fluorescence microscopy and analyzing the data with available programs in ImageJ and Matlab. Depending on availability of the equipment, it could be possible to fabricate the substrates with the new Nanoscribe 3D printer.