Living micro organisms and their strategy to survive the micro scale world has attracted interests from a wide range of scientists spacing from biologists and chemists to mathematicians and also a great (costantly growing) number of physicists. The laws governing phenomena linked to life at the micro scale are still largely unknown: a rising interest is going to the interactions between the organisms and the surrounding environment.
The interactions between cells of the same species and their strategy to move at very low Reynolds number have been object of many recent publications: still the interactions with outer world is largely unexplored. In my project I'd like to find models and to make predictions about how does the outer world can affect motility.
In fact with active (light, chemical gradients...) or passive (thoughtfully shaped) devices it's recently become possible to manipulate entire populations of micro swimmers in order to achieve different results like the separation of different species or the creation of a flow in a spatial region.
Once again only few configurations have been tested for photosynthetic and phototactic species: in particular, the experiments carried on so far, deal with very simple spatial configurations of the stimuli like a uniform light field or a regularly patterned boundary.
No experimental data have been gathered in cases like non uniform light fields or 2D geometrical configurations.
Taking advantage of the contemporary light microscopy techniques and image analysis tools, other than microfluidic devices fabrication, my intent is to look deeply into how complex setups can affect motility taking as a model the unicellular algae Chlamidomonas Reinhardtii, widely used as a model system due to the very standardized configuration of the eucariotic flagella.