Disrupting the wall accumulation of human sperm cells by artificial corrugation

Abstract

Many self-propelled microorganisms are attracted to surfaces. This makes their dynamics in restricted geometries very different from that observed in the bulk. Swimming along walls is beneficial for directing and sorting cells, but may be detrimental if homogeneous populations are desired, such as in counting microchambers. In this work, we characterize the motion of human sperm cells $60\mu m$ long, strongly confined to $25\mu m$ shallow chambers. We investigate the nature of the cell trajectories between the confining surfaces and their accumulation near the borders. Observed cell trajectories are composed of a succession of quasi-circular and quasi-linear segments. This suggests that the cells follow a path of intermittent trappings near the top and bottom surfaces separated by stretches of quasi-free motion in between the two surfaces, as confirmed by depth resolved confocal microscopy studies. We show that the introduction of artificial petal-shaped corrugation in the lateral boundaries removes the tendency of cells to accumulate near the borders, an effect which we hypothesize may be valuable for microfluidic applications in biomedicine.

arXiv comment9 pages, latex. In accepted version on April 14, v2: abstract modified, information added to Sec. II.A and experiments added to Sec. III.A and Fig.3. Sec. III.C was deleted. Requested references added

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Cited by in corpus (5)

• Hydrodynamics of Micro-swimmers in Films
• Giant adsorption of microswimmers: duality of shape asymmetry and wall curvature
• Near-wall hydrodynamic slip triggers swimming state transition of microorganisms
• Deformation of a soft boundary induced and enhanced by enclosed active particles
• Confinement induced three-dimensional trajectories of microswimmers in rectangular channels