Controlling Choanoflagellates with Efficient Microfluidic Devices

J. SPARACINO; G.L.MIÑO; M. A. R. KOEHL; N. KING; R. STOCKER; A.J. BANCHIO; V.I. MARCONI

Heidelberg

Conferencia; EMBL Conference - Microfluidics; 2016

European Molecular Biology Laboratory

ChoanoflagellatesSalpingoeca rosetta, the closest relatives of the animal,differentiate in two types of solitary cells: (a) slow and large and(b) fast and small. The ecological relevance in the differentiationbetween these two types of swimmers, is still not clear and achallenge. Fast swimmer can be a dispersal stage that allows betterfood searching strategy. Recently it has been shown that fastswimmers respond to gradients of pH [1]. Moreover, solitary swimmerscan be related to gametes differentiation. These are the reasons whyan efficient separation of these two swimmer populations could beessential.Following our sperm studies [2] on directed transport withmicrofluidics devices, we measure the cell motilities with itsrelevant parameters. Then we propose a phenomenological 2D-model fortheir dynamics under microconfinement into a flat device divided by awall of asymmetric obstacles separated by micro-openings. To optimizethe device geometry for directing the cells, we systematically studythe transport efficiency by solving the equations of motion using themeasured parameters.The slow cells swim remarkably different from the fast cells,being their trajectories strongly tortuous. As a consequence, thefast choanoflagellates are more efficiently directed for a wide rangeof obstacle wall geometries while the slow cells are harder todirect, independently of the geometry. For both populations, narroweropenings of similar size to the cell dimension, are more efficientrectifiers as well as devices with greater obstacle's radii.Even more, due to the clear differences between fast and slowchoanoflagellates rectification results, an efficient sorter deviceof mixed populations could be designed.[1] G. Miño et al, preprint 2016. [2] Guidobaldi et al, PRE 2014and Biomicrofluidics 2015.p { margin-bottom: 0.25cm; line-height: 120%; background: transparent }