IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Modeling and Controlling choanoaflagellates transport with asymmetric micro-constrictions
Autor/es:
J. SPARACINO; G L. MIÑO; M. A. R. KOEHL; N. KING; R. STOCKER; A. J. BANCHIO; V. I. MARCONI
Lugar:
Bonn
Reunión:
Conferencia; Jülich Soft Matter Days; 2015
Resumen:
In evolutionary biology choanoflagellates are broadly investigated as the closest living relatives of the animal ancestors. Under diverse environmental cues, choanoflagellate Salpingoeca rosetta can differentiate in two types of solitary cells with different swimming strategy and size:(i) slow and large and (ii) fast and small. It is known that under nutrient limiting conditions, they experience an haploid-to-diploid transition, evidenced by the presence of gametes. It is interesting to determine if there is a connection between the two types of cells and the male and female gametes.In order to efficiently direct choanoflagellates we have measured their motilities to determine the relevant parameters to describe the cell dynamics. We present a phenomenological 2D?model for the choanoflagellate dynamics under microconfinement into a flat device divided by a wall of asymmetric obstacles separated by microopenings. To optimize the geometry of the obstacle wall for directing the cell populations, we systematically study the directed transport efficiency by solving our set of dynamical equations using Langevin dynamics, with experimental parameters for the cell motilities and sizes. The slow cells swim remarkably different from the fast cells, being their trajectories strongly tortuous. As a consequence, the fast choanoflagellates are more efficiently directed for a wide range of obstacle wall geometries while the slow cells are harder to direct, independently of the geometry. For both populations, narrower openings of similar size to the cell dimension, are more efficient rectifiers as well as devices with greater obstacle?s radii. These results could be counterintuitive, but are understood for the observed specific cells swimming along walls: fast cells with straight tracks are able to take advantage of the device geometry to be directed, in opposite to the slow cells with a more Brownian strategy to swim.Based on our observations and predictions for separated populations, we conclude that it is important to characterize rigorously as a first step each microswimmer motility in order to control them. Even more, due to the clear differences between fast and slow choanoflagellates rectification results, an efficient sorter device of mixed populations could be designed for further application in evolutionary biology.