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Updated: Feb 18, 2026
Fluorimetric Techniques for the Assessment of Sperm Membranes
Published on: November 28, 2018
Comparison of the external physical damages between laser-assisted and mechanical immobilized human sperm using
1Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong SAR.
Abstract:
We aim to visualize the external physical damages and distinct external phenotypic effects between mechanical and laser-assisted immobilized human spermatozoa using scanning electronic microscopy (SEM). Human spermatozoa were immobilized mechanically or with laser assistance for SEM examination and the membrane integrities were checked on both types of immobilized spermatozoa. We found evidence of external damages at SEM level on mechanically kinked sperm, but not on laser-assisted immobilized sperm. Although no external damage was found on laser-assist immobilized sperm, there were two distinct types of morphological changes when spermatozoa were stricken by infra-red laser. Coiled tails were immediately formed when Laser pulse was applied to the sperm end piece area, whereas laser applied to the sperm principal piece area resulted in a sharp bend of sperm tails. Sperm immobilized by laser did not exhibit any morphological change if the laser did not hit within the on-screen central target zone or if the laser hit the sperm mid piece or head. Our modified membrane integrity assay revealed that the external membrane of more than half of the laser-assisted immobilized sperm remained intact. In conclusion, mechanical immobilization produced membrane damages whilst laser-assisted immobilization did not result in any external membrane damages besides morphological changes at SEM level.
Insights
Mechanical immobilization of human sperm causes external membrane damage, unlike laser-assisted immobilization. Laser immobilization results in distinct morphological changes like coiled or bent tails without membrane damage, as seen via scanning electron microscopy (SEM).
Area of Science:
- Reproductive Biology
- Biophysics
- Microscopy Techniques
Background:
- Assessing sperm integrity is crucial for reproductive medicine and fertility studies.
- Traditional methods for sperm immobilization can introduce artifacts, potentially affecting integrity assessments.
- Scanning electron microscopy (SEM) offers high-resolution visualization of cellular structures.
Purpose of the Study:
- To compare external physical damages and phenotypic effects of mechanical versus laser-assisted immobilization on human spermatozoa.
- To evaluate membrane integrity in human spermatozoa immobilized by different methods using SEM.
Main Methods:
- Human spermatozoa were immobilized using two methods: mechanical manipulation and laser assistance.
- Scanning electron microscopy (SEM) was employed to examine the external morphology and membrane integrity of immobilized spermatozoa.
- A modified membrane integrity assay was utilized to quantify membrane preservation.
Main Results:
- SEM revealed distinct external damages on mechanically immobilized spermatozoa (kinked sperm).
- Laser-assisted immobilization did not cause external membrane damage; however, distinct morphological changes were observed, including coiled tails (laser on end piece) and sharp bends (laser on principal piece).
- The external membrane of over half of the laser-assisted immobilized spermatozoa remained intact, confirmed by the modified integrity assay.
Conclusions:
- Mechanical immobilization leads to membrane damage in human spermatozoa.
- Laser-assisted immobilization is a gentler method, preserving external membrane integrity while inducing specific morphological alterations.
- SEM is effective in visualizing subtle differences in sperm immobilization techniques and their impact on sperm structure.
