title: 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 μm long, strongly confined to ∼25 μm 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.
authors.affiliation: IIByT-CONICET and FCEFyN, Universidad Nacional de Córdoba , X5016GCA Córdoba, Argentina.
authors.forename: H A
authors.identifier: 0000-0002-5033-2981
authors.initials: HA
authors.lastname: Guidobaldi
authors.affiliation: Institute for Nanoscale Physics and Chemistry , KU Leuven, B-3001 Leuven, Belgium.
authors.forename: Y
authors.initials: Y
authors.lastname: Jeyaram
authors.affiliation: FaMAF, Universidad Nacional de Córdoba and IFEG-CONICET , X5000HUA Córdoba, Argentina.
authors.forename: C A
authors.initials: CA
authors.lastname: Condat
authors.affiliation: IIByT-CONICET and FCEFyN, Universidad Nacional de Córdoba , X5016GCA Córdoba, Argentina.
authors.forename: M
authors.initials: M
authors.lastname: Oviedo
authors.affiliation: FaMAF, Universidad Nacional de Córdoba and IFEG-CONICET , X5000HUA Córdoba, Argentina.
authors.forename: I
authors.initials: I
authors.lastname: Berdakin
authors.affiliation: Institute for Nanoscale Physics and Chemistry , KU Leuven, B-3001 Leuven, Belgium.
authors.forename: V V
authors.initials: VV
authors.lastname: Moshchalkov
authors.affiliation: IIByT-CONICET and FCEFyN, Universidad Nacional de Córdoba , X5016GCA Córdoba, Argentina.
authors.forename: L C
authors.initials: LC
authors.lastname: Giojalas
authors.affiliation: Départment de Physique, Université de Liège , B-4000 Sart Tilman, Belgium.
authors.forename: A V
authors.initials: AV
authors.lastname: Silhanek
authors.affiliation: FaMAF, Universidad Nacional de Córdoba and IFEG-CONICET , X5000HUA Córdoba, Argentina.
authors.forename: V I
authors.initials: VI
authors.lastname: Marconi