Scientists are developing new low cost sperm sorting devices that can select the best sperm cells for assisted reproductive technologies such as in-vitro fertilisation, increasing the chances of a successful pregnancy. The competition is fierce and only the strongest survive the obstacle course within the female reproductive tract. Of the millions of sperm that enter the vagina, only about 10 or so make it to the oocyte or egg, demonstrating how rigorous the natural sperm selection process really is.

The most commonly used or conventional method for assisted reproductive technologies involves a technique called centrifugation. This technique spins the sperm samples around and at the end, the most motile sperm are used for reproductive medicine. Although this method is efficient at selecting motile and normal sperm, the process is problematic because it tends to increase levels of chemicals that cause DNA damage. This technique is less efficient at selecting mature sperm or getting rid of sperm that are near death.

Waseem Asghar from Florida Atlantic University in the US is currently working on developing easy-to-use and inexpensive sperm sorting devices that have applications in intrauterine insemination, intracytoplasmic sperm injection, and in vitro fertilisation.

Asghar’s device consists of one inlet for the injection of a raw unprocessed semen sample and two plastic chambers separated by porous membrane. The most healthy and motile sperm swim through the porous membrane leaving behind less functional and dead sperm in the bottom chamber.

Compared to other techniques used for assisted reproductive technologies, the use of the microfluidic device resulted in significantly lower rates of DNA damage and improved sperm recovery using this method.