HDR – Vincent Studer

Progress in cell biology requires advanced methods to quantitatively analyze the response of individual cells to spatially and temporally controlled stimulations. Classical methods to apply chemical stimulations, which are often based on the diffusion of solutes released by micropipettes, have long suffered from a poor spatial and temporal resolution. Techniques to overcome this limitation have recently emerged, following advances in the fabrication of microfluidic devices. Microfluidics provide an alternative approach to tailor the chemical environment at the micron scale, and it has been fruitfully employed in chemotactic assays with non-neuronal eukaryotic cells. However, applications of microfluidics to neuron guidance have so far remained limited. This can be primarily attributed to the sensitivity of neuronal cells to culture and fluidic conditions in microcircuits. In the last few years we have developed a range of microfluidic systems, which overcome this limitation. We have applied them to the study of neuronal chemotaxis in a quantitative manner. Neuron guidance is triggered by extracellular signals called “guidance cues”, which determine the direction of axon growth to reach the appropriate target. We first probed the directional sensing of nerve growth cones (the motile tip of axons) in controlled chemical landscapes. Nerve growth cones are chemical sensors that convert graded extracellular cues into oriented axonal motion. We also used microfluidic devices to test the combinatorial effect of multiple guidance cues on axon guidance. It has been recently demonstrated that the combination of two guidance cues, can generate an attractant activity that none of these guidance factors has alone. Using innovative shear-free microfluidic device, we have successfully reproduced and precised these results in vitro.

Vincent Studer
Chargé de recherche CNRS
IINS / Université Bordeaux (UMR 5297)