title: Microfluidics and numerical simulation as methods for standardization of zebrafish sperm cell activation.
abstract: Sperm cell activation plays a critical role in a range of biological and engineering processes, from fertilization to cryopreservation protocol evaluation. Across a range of species, ionic and osmotic effects have been discovered that lead to activation. Sperm cells of zebrafish (Danio rerio) initiate motility in a hypoosmotic environment. In this study, we employ a microfluidic mixer for the purpose of rapidly diluting the extracellular medium to initiate the onset of cell motility. The use of a microchannel offers a rapid and reproducible mixing profile throughout the device. This greatly reduces variability from trial to trial relative to the current methods of analysis. Coupling these experiments with numerical simulations, we were able to investigate the dynamics of intracellular osmolality as each cell moves along its path through the micromixer. Our results suggest that intracellular osmolality, and hence intracellular ion concentration, only slightly decreases, contrary to the common thought that larger changes in these parameters are required for activation. Utilizing this framework, microfluidics for controlled extracellular environments and associated numerical modeling, has practical applicability in standardizing high-throughput aquatic sperm activation, and more fundamentally, investigations of the intracellular environment leading to motility.
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Scherr
authors.forename: Gerald L
authors.initials: GL
authors.lastname: Knapp
authors.forename: Amy
authors.initials: A
authors.lastname: Guitreau
authors.forename: Daniel Sang-Won
authors.initials: DS
authors.lastname: Park
authors.forename: Terrence
authors.initials: T
authors.lastname: Tiersch
authors.forename: Krishnaswamy
authors.initials: K
authors.lastname: Nandakumar
authors.forename: W Todd
authors.initials: WT
authors.lastname: Monroe
mesh_terms: D000818:Animals; D004867:Equipment Design; D019544:Equipment Failure Analysis; D056656:Lab-On-A-Chip Devices / Q000592:standards*; D008297:Male; D008954:Models, Biological; D009997:Osmotic Pressure; D012016:Reference Values; D015203:Reproducibility of Results; D055101:Semen Analysis / Q000379:methods* / Q000592:standards*; D012680:Sensitivity and Specificity; D013081:Sperm Motility / Q000502:physiology*; D015027:Zebrafish / Q000502:physiology*