Mechanical investigation of wall-less plant cells using microfluidics

Each cell within a plant experiences a myriad of mechanical and chemical cues that direct growth and development. Selective application of such cues and live-imaging of the resulting cellular responses are challenging within the tissue context. For this reason, I have developed a microfluidic device, called Ψ-trap, for mechano-chemical investigations of single cells, by combining microfluidic technology and automated live-imaging. The platform allows the microscopic time-course observation of individual plant cells within a heterogeneous population, such as leaf cells, while applying precise chemical or physical stimuli. As a pilot study I have quantitatively monitored the cellular expansion of cell wall-less plant cells, called protoplasts. I have further shown that the application of cyclic compression forces to single cells inside the Ψ-trap can be used to study the mechanical volume and shape control of single protoplasts from different developmental conditions. To separate the intracellular and extracellular factors that influence the cellular shape control, I have created a complementary microfluidic shape induction device, called the Ψ-constriction trap. My results suggest wall-less shape retainment upon mechanical compression in plant cells