The cooperative impact of flow and viscosity on sperm flagellar energetics in biomimetic environments

Farin Yazdan Parast, Avinash S. Gaikwad, Ranganathan Prabhakar, Moira K. O'Bryan, Reza Nosrati

Research output: Contribution to journalArticleResearchpeer-review


Complex rheological properties of the female reproductive tract serve as a long-range guidance mechanism for sperm. However, conventional microscopy methods and population-level studies have restricted our understanding of the combined effects of flow and viscosity on sperm flagellar beating behavior at the single-cell level. Here, using microfluidics, we study individual sperm flagellar dynamics within a physiologically relevant range of viscosity and shear rate. Our results indicate that an increase in shear rate from 0 to 6 s−1 at 75 mPa s reduces the flagellar curvature by 20%, while the peak energy occurs at a shear rate of 3 s−1—a favorable shear rate for sperm rheotaxis. Viscosity has a more dominant influence than shear rate on the flagellar waveform, and the synergistic effect of flow and viscosity promotes energy-efficient beating behavior. Our findings provide new insights into the complex interplay between the environment of the female reproductive tract and sperm function in facilitating fertilization.

Original languageEnglish
Article number101646
Number of pages15
JournalCell Reports Physical Science
Issue number11
Publication statusPublished - 15 Nov 2023


  • flagellar energetics
  • flagellar waveform
  • reproduction
  • rheotaxis
  • sperm motility
  • viscosity

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