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Remote control of a microswimmer through pressure waves

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Microswimmers are a research subject extremely fruitful for a few years, both on the fundamental point of view (motility at small scale) and for more applicative purposes (e.g. targetted drug delivery, or conception of nanorobots with remote control). better and on the During development, embryos have to change their shape (originally the one of their egg) to form an organism. Forces are exerted among the cells, through a net of polymers transducting biochemical energy into mechanical constraints. If biologists can explain how genetic regulation locally triggers this mechanical activity in the embryo, no model yet does satisfactorily explain how these forces allow to obtain the deformations that are experimentally observed with an impressive reproductibility.

The internship takes place during the whole conception process of stable and robust microswimmers, fully synthetized with high throughput and remotely controlable by pressure waves. The principle of the swimming lies in the periodic deformation of hollow elastic miscroshells undergoing pressure oscillations (e.g. dispensed by an echographic device). To understand and optimize the swimming, a necessary stage consists in studying the upscaled system in an experiment designed to keep constant the adimensionalized numbers. The dynamics of a single swimmer has been studied on the devoted device. Now we are interested in the coupling between two or more swimmers, in order to forecast how to control the direction of a rigid assembly (first step toward the conception of a nanorobot).

The work to be done is experimental, and will use the upscaled experiment. Hydrodynamic coupling between different swimmers will be studied in order to understand and optimize their cooperativity, according the amplitude and frequency of the pressure wave. For this, fabrication of new swimmers (modification of dimensions or materials) may occur. Experimental measurements essentially come from video recording and image treatment for data acquisition. If necessary, flows will be caracterized by article image velocimetry coupled to laser map illumination.

Required skills : Internship requires a taste for observation, experimentation and fine manipulation. On the theoretical point of view, the knowledge of basic concepts in elasticity and hydrodynamics may help.

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Micro swimmers