Plants are able to sense their mechanical environment. For example, leaves of touch-sensitive plants, such as mimosa (Mimosa pudica) and Venus flytrap (Dionaea muscipula), rapidly fold and bend in response to stimulation or close to catch a prey, respectively. This is true also at a smaller scale. Morphogenesis, both at the cell and tissue level, involves mechanical signals that influence specific patterns of gene expression and trigger cytoskeletal reorganizations. How mechanical stress is perceived and how this signal is transduced into the cell to exert these effects is still poorly understood, and remains challenging questions in both the plant and animal community. To definitively prove that mechanical force serves as a signal able to activate specific downstream pathways, it is needed to simplify the system.
For that, I propose to use protoplasts, intact cells without the cell wall since they contain all the cellular machinery and they are able to respond to mechanical stress. In order to induce mechanical stress on immobilized single cells, we will develop a microfluidic chip to trap protoplasts and to induce controlled mechanical stress. The benefit of trapping cells by microfluidic is that it allows the long-term monitoring of individual living plant cells. Thanks to a constant exchange of nutrients and oxygen, cell growth in a microfluidic chip proceeds normally. The mechanical stimulus is tightly controlled by the flow rate of the Fusion 200 Two-Channel Syringe Pump, which makes it possible to produce a controlled mechanical stimulus.
We are currently at the developmental step of the microfluidic device, meaning that I am right now producing the SU-8 based master. This will be used as a 3D-negative template of the PDMS based device. Once the PDMS based device is produced I will use a 20 years-old peristaltic pump to start to see if my device is working. It is clear, that an old peristaltic pump does not fit the requirements of the planned experiments. This is why we need to have a good syringe pump and the Fusion 200 high precision syringe pump seems to be good at least to start. Meaning that we will need another syringe pump, once the system is set up.
Article By: Katharina Gabor at Eberhard-Karls University Tuebingen