Chlamydomonas Reinhardtii (CR) is a motile unicellular green alga that is sometimes referred to, non-scientifically, as Chlamy. CR is a biflaggelated microswimmer that moves in breaststroke motions allowing them to displacement the fluid around them. Certain strains of CR exhibit phototactic abilities i.e. swimming towards(positive) or away(negative) from a light source. 

Previous work in theoretical models and experiments utilizing artificial microswimmers found that for populations of microswimmers moving in the same direction, their cargo transport abilities are enhanced. In essence, they are able to move more micro-sized objects like particles. Therefore it is hypothesized that controlling this collective movement can help transport small particles.

My goal for my project this summer was to test this hypothesis experimentally utilizing Chlamydomonas Reinhardtii and their phototactic abilities. I accomplished this by culturing two strains of CR, CC124 (positively phototactic), and CC125 (negatively phototactic). I used an external light source, a microfluidic channel set up in order to control the movement direction of CR in a confined environment. Lastly, I utilized fluorescent tracer particles and the microscope in order to track the movement of both the particles and CR using high-speed microscopy. I was able to see entrainment events as well as collective phototaxis behavior in CR.