Hydrophobic silicone elastomer chamber for recording trajectories of motile sperms without adsorption

K. Matsuura, H. Funahashi
Okayama University, JP

Keywords: porcine sperm motility, silicone elastomer, adsorption, trajectories, artificial insemination


Sperm motility analysis is a representative method for evaluation of male fertility, since motility correlates with viability. The conventional method, commonly referred to as Computer-Assisted Sperm Analysis (CASA), to records motility and linear velocity (LV) utilizing a microscope with a charge coupled device. The advantage of CASA over manual observation is the absence of subjective calibration. It is difficult to record trajectories of motile porcine sperms and investigate LV related to fertility because sperms often adsorb to glass and plastic, which remarkably decreases their motility. To record the trajectories of motile sperms and investigate their velocity distribution quantitatively under a microscope, the use of transparent materials that do not promote adsorption of motile sperms is necessary. The candidate material is hydrophobic silicone elastomer poly(dimethylsiloxane) (PDMS), because it is nontoxic, transparent, inexpensive, and easy to handle. For observation of motile sperms, diluted semen is usually sandwiched between hydrophilic glass slides. However, a hydrophobic chamber should be designed to reduce height of droplet on the material to prevent overlap of motile sperm images. We developed the preparation to decrease the focal depth. Semen was sandwiched with two PDMS sheets.