title: Reduced curvilinear velocity of boar sperm on substrates with increased hydrophobicity.
abstract: The curvilinear velocity (VCL) of boar spermatozoa between standard microscopy glassware decreases when the slides are coated with the hydrophobic polymer polystyrene (PS) compared with the less hydrophobic poly(methyl methacrylate) (PMMA) coating. Sperm from three boars were observed and analyzed using particle tracking software. The VCL did not differ significantly between coatings of different thickness, indicating no penetration of the sperm into the coating and that only the surface layer of the polymer film interacts with the sperm and buffer medium. The VCL of sperm between PS-coated surfaces was significantly reduced compared with PMMA surfaces (P < 0.0001), and this was attributed to a stronger hydrophobic effect between PS and water. The size of this effect varied between different boars, perhaps as a consequence of variations in hydrophobicity of sperm from different boars or different ejaculates. The modification of surface properties in this way may improve our understanding of sperm behavior and may provide improvements to assisted conception techniques as animal or human sperm used in assisted conception are frequently manipulated in laboratory plastics as part of diagnostic procedures (e.g., semen analysis) or before injection into an oocyte or during the co-incubation with the oocyte in IVF. Controlling the velocity of sperm using the interaction properties of inert polymer coatings could lead to new sperm selection procedures for clinical use or the development of model systems to better understand sperm-surface interactions.
authors.affiliation: Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK. Electronic address: m.mears@sheffield.ac.uk.
authors.forename: Matthew
authors.initials: M
authors.lastname: Mears
authors.affiliation: Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Kennelly
authors.affiliation: Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield, UK.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Howse
authors.affiliation: School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK.
authors.forename: Drew S
authors.initials: DS
authors.lastname: Tarmey
authors.affiliation: Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Geoghegan
authors.affiliation: Academic Unit of Reproductive and Developmental Medicine, The University of Sheffield, Sheffield, UK.
authors.forename: Allan A
authors.initials: AA
authors.lastname: Pacey
mesh_terms: D000818:Animals; D057927:Hydrophobic and Hydrophilic Interactions; D008297:Male; D010969:Plastics; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry; D055101:Semen Analysis; D013081:Sperm Motility / Q000502:physiology*; D013094:Spermatozoa / Q000737:chemistry*; D013499:Surface Properties; D013552:Swine; D014867:Water / Q000737:chemistry
chemical_list: D010969:Plastics; D011137:Polystyrenes; D014867:Water; D019904:Polymethyl Methacrylate
keywords: Computer assisted sperm analysis; Hydrophobicity; Motility; Surface interaction; Tracking