Use of microfluidics to sort stallion sperm for intracytoplasmic sperm injection.

This research explores the use of microfluidics in sorting stallion sperm in order to improve characteristics for producing healthy embryos. The study found that microfluidic sorting significantly increased the motility, morphology, viability, and DNA integrity of sperm, producing results equal or superior to existing techniques.

Microfluidic Sorting and Its Benefits

• In this study, techniques for sorting stallion sperm were evaluated including microfluidics, single-layer colloidal centrifugation (SLC) and swim-up (SU). Initially, semen samples were sorted using microfluidic methods and compared to the baseline sample statistics. The researchers found that microfluidic sorting considerably improved motility, morphology, viability, and membrane and DNA integrity of sperm.
• This technique capitalizes on small-scale physics to isolate and analyze sperm cells. Microfluidic channels are designed such that sperm with higher motility and better morphology (i.e. healthier) can swim through more rapidly than those with lower motility or morphology.

Comparing Microfluidic Sorting, Single-Layer Colloidal Centrifugation, and Swim-Up Methods

• In the second experiment, microfluidic sorting was benchmarked against SLC and SU methods. The results suggested that to a great extent, microfluidics and SLC produced comparable results with respect to motility, viability, and membrane integrity. Although, sperm sorted using microfluidics demonstrated significantly better morphology and DNA integrity compared to SLC. SU was found to be the least effective method among all.

Evaluating the Effect of Sperm Sorting on Intracytoplasmic Sperm Injection (ICSI)

• The third experiment was designed to validate the effects of microfluidic and SLC sorting methods on further stages of in vitro fertilization, specifically intracytoplasmic sperm injection (ICSI). This procedure involves injecting a single sperm cell directly into an egg to achieve fertilization.
• Following both sorting techniques, the sperm were then used for ICSI. Both methods resulted in similar motility, morphology and DNA integrity. However, microfluidics still demonstrated greater improvement on the viability of the sperm compared to SLC.
• The study concluded that irrespective of the sorting method used, it did not lead to any substantial improvement in sperm membrane integrity. Interestingly, sorting with microfluidics or SLC before ICSI resulted in similar rates of embryo cleavage and blastocyst development.

Conclusion

• The research concluded that microfluidic sorting enhanced sperm population parameters, outperforming or matching other traditional sorting techniques. Microfluidics presents an efficient method to improve the quality of the sperm samples used for ICSI, thereby potentially increasing the success rates of in vitro fertilization.