title: Two-dimensional slither swimming of sperm within a micrometre of a surface.
abstract: Sperm motion near surfaces plays a crucial role in fertilization, but the nature of this motion has not been resolved. Using total internal reflection fluorescence microscopy, we selectively imaged motile human and bull sperm located within one micron of a surface, revealing a distinct two-dimensional (2D) 'slither' swimming mode whereby the full cell length (50-80 μm) is confined within 1 μm of a surface. This behaviour is distinct from bulk and near-wall swimming modes where the flagellar wave is helical and the head continuously rotates. The slither mode is intermittent (∼1 s, ∼70 μm), and in human sperm, is observed only for viscosities over 20 mPa·s. Bull sperm are slower in this surface-confined swimming mode, owing to a decrease in their flagellar wave amplitude. In contrast, human sperm are ∼50% faster-suggesting a strategy that is well suited to the highly viscous and confined lumen within the human fallopian tube.
authors.affiliation: Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G8.
authors.forename: Reza
authors.initials: R
authors.lastname: Nosrati
authors.affiliation: Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.|Institute of Biomaterials and Biomedical Engineering, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1.
authors.forename: Amine
authors.initials: A
authors.lastname: Driouchi
authors.affiliation: Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.|Institute of Biomaterials and Biomedical Engineering, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1.|Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3E5.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Yip
authors.affiliation: Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G8.
authors.forename: David
authors.initials: D
authors.lastname: Sinton
mesh_terms: D000818:Animals; D002417:Cattle; D006801:Humans; D008297:Male; D013045:Species Specificity; D013081:Sperm Motility / Q000502:physiology*; D013094:Spermatozoa / Q000502:physiology*