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Journal of Biomedical Optics • Open Access

Effects of viscosity on sperm motility studied with optical tweezers
Author(s): Nicholas Hyun; Charlie Chandsawangbhuwana; Collin Yang-Wong; Michael W. Berns; Qingyuan Zhu; Linda Z. Shi

Paper Abstract

The purpose of this study is to analyze human sperm motility and energetics in media with different viscosities. Multiple experiments were performed to collect motility parameters using customized computer tracking software that measures the curvilinear velocity (VCL) and the minimum laser power (Pesc) necessary to hold an individual sperm in an optical trap. The Pesc was measured by using a 1064 nm Nd:YVO4 continuous wave laser that optically traps motile sperm at a power of 450 mW in the focused trap spot. The VCL was measured frame by frame before trapping. In order to study sperm energetics under different viscous conditions sperm were labeled with the fluorescent dye DiOC6(3) to measure membrane potentials of mitochondria in the sperm midpiece. Fluorescence intensity was measured before and during trapping. The results demonstrate a decrease in VCL but an increase in Pesc with increasing viscosity. Fluorescent intensity is the same regardless of the viscosity level indicating no change in sperm energetics. The results suggest that, under the conditions tested, viscosity physically affects the mechanical properties of sperm motility rather than the chemical pathways associated with energetics.

Paper Details

Date Published: 6 March 2012
PDF: 7 pages
J. Biomed. Opt. 17(2) 025005 doi: 10.1117/1.JBO.17.2.025005
Published in: Journal of Biomedical Optics Volume 17, Issue 2
Show Author Affiliations
Nicholas Hyun, Univ. of California, San Diego (United States)
Charlie Chandsawangbhuwana, Univ. of California, San Diego (United States)
Collin Yang-Wong, Univ. of California, San Diego (United States)
Michael W. Berns, Beckman Laser Institute and Medical Clinic (United States)
Qingyuan Zhu, Univ. of California, San Diego (United States)
Linda Z. Shi, Univ. of California, San Diego (United States)

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