Microfluidic Device Corrals Viable Sperm for IVF

Researchers at Cornell University have developed a microfluidic device to rapidly isolate the strongest and fastest sperm from a sperm sample. The technique should help technicians during the IVF process, as the current method of isolating the most viable sperm is painstaking and can take hours for the manual effort to pay off.

During IVF, isolating the strongest sperm from a sperm sample is important as it gives couples the best possible chance of conceiving. However, this is performed manually, and is an arduous process. “Trying to find the highly motile sperm has been difficult to do, but this improves the chances of insemination,” said Alireza Abbaspourrad, a researcher involved in the latest study. “The older method is tedious, time-consuming and not efficient. It’s the time that laboratory technicians and physicians expend that makes the process expensive.”

The new device takes advantage of sperm’s tendency to face into a current, which is called rheotaxis. “Here, we took advantage of sperm’s natural tendency to redirect against fluid flow, once the sperm reach a certain velocity,” said Soon Hon Cheong, another researcher involved in the study. “Once the sperm detect interference, they can use it to swim upstream. That’s when we can trap them. We could separate the good sperm from the not-so-strong in a reasonably elegant way. We are able to fine-tune our selection process.”

The device consists of a microfluidic channel through which the sperm sample flows. Its design is relatively straight-forward, and the capture method is completely passive. The researchers included a “C” shaped corral, and a retaining wall. This structure causes interference in the fluid flow, which encourages the strongest swimmers to enter, but traps them once inside. Using the device means that the process of sperm selection takes just minutes, compared with hours spent manually selecting sperm.

Here’s a short video of the new device in action:

Study in PNAS: Rheotaxis-based separation of sperm with progressive motility using a microfluidic corral system…

Via: Cornell University…