Near-wall dynamics of microconfined sperm cells.

MARÍA NOEL GALLEA; LAURA CECILIA GIOJALAS; VERÓNICA IRIS MARCONI; GASTÓN LEONARDO MIÑO; HECTOR ALEJANDOR GUIDOBALDI; MATÍAS ALEJANDRO BETTERA MARCAT; MARISA ANGELICA CUBILLA; ADOLFO JAVIER BANCHIO

Córdoba

Congreso; II Brazil-Argentine Microfluidics Congress & V Congreso de Microfluídica Argentina; 2019

Facultad de Matemática, Astronomía, Física y Computación, UNC

The boundary-following swimming of human spermatozoa its a key feature to be exploited by microfluidics device designing, with applications in ART (assisted reproductive tech- nology), fertility diagnosis and medical research. We have shown that it is possible to guide the movement of a population of human sperm and accumulate them [Guidobaldi et al., PRE 2014] or to manipulate them with the appropriate wall curvature to achieve an homogeneous distribution of cells [Guidobaldi et al., Biomicrofluidics 2015]. In short, the design of microfluidic devices requires a deep understanding of the interactions of cells with the boundaries. Then, we studied the motility of sperm cells swimming near walls under conditions of micro-confinement and we obtained the velocity dynamics in the approaching- aligning-swimming-escape events due to lateral wall following. The device is 20μm depth, smaller than the sperm cells length. We observed a velocity reduction when a sperm en- counters a lateral wall and progressively recovers its velocity as its swimming orientation becomes parallel to it. With simple phenomenological model, we accomplish to repro- duce population dynamics of sperms swimming near walls. Different simple orientational dynamics were proposed and compared with experiments, linear and cubic functionality with incidence angle, as well as the limits of no orientational and instantaneous dynamics. By comparison with experimental velocity and density distribution, we found the optimalvalue of the free parameter for reproducing the population dynamics.