Isolation of motile spermatozoa from semen samples using microfluidics

Abstract

A microfluidic device was designed with two parallel laminar flow channels where non-motile spermatozoa and debris would flow along their initial streamlines and exit one outlet, whereas motile spermatozoa had an opportunity to swim into a parallel stream and exit a separate outlet. Motile sperm samples were prepared with density gradient separation (n = 5). Sperm motility was assessed the following day after exposing aliquots to polydimethylsiloxane (PDMS) used to construct the device. There was no difference in sperm motility when compared with unexposed aliquots (P > 0.05). Unprocessed semen samples (n = 10) were placed in wider channels and sperm motility and strict morphology were assessed from sorted outlets. Sperm motility increased from 44 +/- 4.5% to 98 +/- 0.4% (P < 0.05) and morphology increased from 10 +/- 1.05% to 22 +/- 3.3% (P < 0.05) following processing. Finally, density gradient prepared samples (n = 6) containing 5 x 10(6) motile spermatozoa/ml and 50 x 10(6) round immature germ cells/ml were sorted and assessed in a similar fashion. The ratio of motile spermatozoa to round immature germ cells in the wide inlet (1:10) was significantly improved in the thin outlet (33:1) (P < 0.05). This microfluidic device provides a novel method for isolating motile, morphologically normal spermatozoa from semen samples without centrifugation. This technology may prove useful in isolating motile spermatozoa from oligozoospermic samples, even with high amounts of non-motile gamete and/or non-gamete cell contamination. A movie sequence showing streaming and sorting of spermatozoa may be purchased for viewing on the internet at www.rbmonline.com/Article/847 (free to web subscribers).

Frequency of Sperm DNA Fragmentation According to Selection Method: Comparison and Relevance of a Microfluidic Device and a Swim-up Procedure

“…A device based on microfluidic flow theory (Sperm Sorter Qualis ® ; Menicon, Kasugai, Japan) has been shown to select morphologically normal spermatozoa with high motility and with no debris [9][10][11][12]. As centrifugation is not necessary for this device, it is possible that it could isolate highly motile spermatozoa with a low frequency of SDF.…”

Application of microfluidic technologies to human assisted reproduction

“…These investigators assessed sperm progression through branching microchannels with a suggestion that such a microfluidic device could displace conventional methods of motility testing in clinical semen analyses. The first reports of using microfluidics for human semen processing and motile sperm isolation with potential therapeutic utility occurred in 2003 Schuster et al, 2003). In these initial reports, it was theorized that one could use the fluid mechanical characteristics of microfluidics for sorting motile sperm from seminal plasma, non-motile sperm and non-motile non-gamete cellular debris.…”

Recent advances in microfluidic diagnostic and treatment systems for assisted reproductive technologies in developing countries

“…Among LOC devices, microfluidic sperm sorting (MFSS) chips have been developed and marketed for motile sperm sorting and use two gravity-driven laminar flows across a microfluidic channel of 50-200 µm [52][53][54][55][56][57][58][59][60][61]. Fluids flowing through the semen inlet (A) and the medium inlet (B) move parallel to each other and exit through respective outlets (A→D and B→C) [53].…”