Technique able to sort for faster sperm

IRVINE, Calif., Aug. 24 (UPI) -- The Universities of California, Irvine and San Diego have developed a rapid new sorting technique to screen for faster sperm.

The laser trap can separate stronger, faster sperm from slower sperm -- faster sperm are more likely to successfully fertilize an egg during in vitro fertilization.

Bing Shao of The University of California, Irvine and colleagues used special cone-shaped lenses called "axicons," which, when combined with a standard lens and a laser, form a ring-shaped focus. The trap acts as a kind of "speed bump" for swimming sperm, depending on the power of the laser used, Shao said.

The technique can also serve to assist in gender selection. Because X sperm are generally heavier and swim slower and Y sperm are lighter and swim faster, it is also possible to use this new technique to separate sperm carrying the gene for a female child from sperm carrying the gene for a male child, the researchers said.

The findings are to be presented at the 91st annual meeting of the Optical Society of America Sept. 16-20 in San Jose, Calif., alongside Laser Science XXIII, the annual meeting of the American Physical Society Division of Laser Science.