Scientists have devised a way to separate the strongest sperm from the rest of the pack in a development that could improve the success rates and speed of IVF.
When it comes to fertilizing an egg, more sperm is better, but strong sperm is best.
Whether a fertility specialist uses one or several sperm to try to fertilize an egg, the stronger these sex cells are, the better the odds that they will successfully fertilize the egg and that the resulting embryo will implant and grow.
Until now, there was no fast way to sort through various sperm, but with Cornell University’s new system, scientists may soon be able to hand pick only the best sperm in a matter of minutes.
A tiny horseshoe-shaped corral traps the strong-swimming sperm that a drawn to go upstream by a retraining wall, helping scientists gather only the highest quality sperm for IVF
In vitro fertilization (IVF) is an expensive but increasingly common – and effective – way for couples who are struggling to conceive naturally to have a baby.
Now more than 10,000 babies have come into the world thanks to IVF.
And the odds that each round or consecutive series of treatments will result in conception have only gotten better.
Fifteen years ago, only about 20 percent of IVF cycles led to a live birth.
Now, it’s up to about 30 percent – though the odds are still higher for younger women and lower for older ones.
Though these odds vary in closest connection with a woman’s age, it takes two to make a baby, and both the count and the quality of a man’s sperm play a significant role in a couple’s fertility odds.
There are a number of forms of IVF when it’s done in the lab, including intracytoplasmic sperm injection (ICSI), in which a single sperm is injected into the egg, as opposed to placing a small amount of semen with multiple sperm in a culture dish with a single egg.
Either way, the strength of the sperm is crucial to ensuring that an egg gets fertilized in the right window of time.
The more that fertility specialists know about the quality of the sperm they are working with, the better.
Sperm motility and count estimators are nothing new: one was described back in 1978, and similar ‘chambers’ are still used, quite effectively.
But it can be a time-consuming matter, and estimating and then tediously separating the sperm once took hours.
Now, the Cornell scientists say they can get not only estimation but separation in a matter of minutes.
The trick is to let the sperm separate themselves.
A key trait of strong sperm is their ability to swim upstream.
The Cornell scientists observed that strong, motile sperm not only have the ability to swim upstream, but will opt to do so when the opportunity presents itself while weaker ones stay the course and go with the flow.
To encourage them to do so, the scientists created a microfluid channel – like a lap pool for sperm – for the reproductive cells of cows to swim through.
They placed a tiny retaining wall and horseshoe-shaped corral in the microfluid. The strong sperm were drawn to the wall and opportunity to swim upstream, while the weaker ones tumbled on by.
Once the strong ones started their retrograded journey, they found themselves funneled into the corral and trapped there.
‘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,’ said study co-auythor Dr Alireza Abbaspourrad.
‘With this method, it’s five minutes instead of several hours.’
He added that the new method is ‘unprecedented’ in its efficiency, and that its ‘benign, passive nature makes it favorable for sperm separation. ‘
There is no way of knowing yet how dramatically the device might improve fertility odds and cut IVF costs and expedite the process, but at the very least it may soon offer fertility specialists another took in their growing kits.