Analytical Sciences

Motility Measurement of a Mouse Sperm by Atomic Force Microscopy

Wesley W. HSIAO,*1,*2,*3 Hsien-Shun LIAO,*1,*4 Hsing-Hung LIN,*2,*3,*5 Ren-Feng DING,*1,*4 Kuang-Yuh HUANG,*4 and Chia-Seng CHANG*1,*2

*1 Institute of Physics, Academia Sinica, Nangang, Taipei 115, Taiwan R.O.C.
*2 Taiwan International Graduate Program—Chemical Biology and Molecular Biophysics, Academia Sinica, Nangang, Taipei 115, Taiwan R.O.C.
*3 College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan R.O.C.
*4 Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan R.O.C.
*5 Genomics Research Center, Academia Sinica, Nangang, Taipei 115, Taiwan R.O.C.

Eukaryotic flagella are responsible for the motile organelles that cause the migration of mammalian sperms. The lashing force and torque of the sperm flagellum contain critical information regarding the sperm health, as important evaluation factors for sperm screening. The objective of the study was to investigate the lashing force and torque of a sperm under physiological conditions using atomic force microscopy (AFM). At a distance of about 18.5 μm from its head-tail junction, a lashing force of 0.96 ± 0.20 nN was measured. Its corresponding lashing torque was 1.77(± 0.37)× 10⁻¹⁴ N·m. The torque increases in proportion to the square of the head-tail junction distance. Our results reasonably conclude that the axonemal motility is linear dependent on the flagellum length of the sperm. Our developed measurement system can consistently determine the lashing force and torque of a sperm, which can contribute to further studies concerning the mechanism of sperm transport and fertilization.

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