Research Training Group 2154 - Materials for Brain

Sandra Sindt

Investigation of cellular mechanotransduction using AFM-based force spectroscopy

Mechanotransduction describes a cellular mechanism as reaction to external, mechanical stimuli. Since this mechanism is not completely understood yet, the major topic of this PhD project is the investigation of mechanotransduction via two different approaches. On the one hand, a combination of Atomic Force Microscopy (AFM) and Traction Force Microscopy (TFM) gives the opportunity to gain a deeper knowledge of how cells interact with their surroundings (related to mechanical aspects), whereas the external, mechanical manipulation of cells to investigate relevant cell-substrate interactions will lead to a deeper knowledge about cell adhesion.
AFM is a well-known and versatile technique to measure cell-cell and/or cell-substrate interactions. In general, a cell is attached to a functionalized AFM cantilever and brought into contact with another cell or a substrate. This gives various possibilities to investigate and manipulate cellular interactions. In our approach, we want to stimulate the cell mechanically to manipulate their adhesion forces.
Furthermore, it is known that adhering cells deform their surrounding via so called traction forces. In TFM, one investigates and measures these forces by tracking the displacement of marker beads embedded in the underlying substrate. In our approach, we want to combine this tracking method with the possibilities of AFM. With this, we will be able to measure traction forces and cell-substrate interaction forces simultaneously.
Another aspect that is closely related to the investigation of mechanotransduction and TFM is the mechanical characterization of soft polymer substrates. It is necessary to precisely and reliably measure the elastic properties of such substrates to calculate traction forces of cells. The AFM is a well-known technique to measure the stiffness/Young’s modulus of substrates. However, there are relevant parameters that are not always considered in the literature. Consequently, a reliable approach to circumvent the arbitrariness of many measurements was realized in this project.