Meisam Zaferani (email): is a fifth-year Ph.D. candidate in Abbaspourrad's Lab at Cornell University. Before joining Cornell, he received his MSc in Applied Physics and BSc in Electrical Engineering from the University of Tehran, Iran. His interdisciplinary Ph.D. research combines theoretical and experimental approaches to investigate the navigational mechanisms associated with mammalian (bovine) sperm migration within the female reproductive tract. On the experimental side, he designs and fabricates miscellaneous microfluidic structures to explore sperm motion within microenvironments and further identify the ambient biophysical and biochemical conditions which promote emergent navigational mechanisms. On the theoretical side, he employs approaches from fluid mechanics, nonlinear dynamics, and statistical physics to develop quantitative models that describe navigational mechanisms using fundamental physical principles.

Talk details: Rheological properties of the environment regulate sperm navigation by controlling the rolling component of motility
The function of sperm rolling around their longitudinal axes has remained unknown for decades. Recently, we found that rolling contributes to sperm navigation within the female reproductive tract as this component of motility is sensitive to ambient fluid viscosity and viscoelasticity. That is, the rheological properties of the swimming media can suppress rolling which subsequently transitions sperm swimming behavior from progressive to diffusive circular motion. We also found that the suppression of rolling by viscosity or viscoelastic changes in the swimming media is reversible. Since the viscosity and viscoelasticity of the fluid within the female tract vary according to functional region, the tract can regulate sperm navigation via controlling the rolling component.