Scientists in Germany have created artificially motorised sperm, propelled by microscopic metal helices.
In a video, they demonstrate how they were able to use a tiny metal helix to direct an immobile sperm towards an egg using rotating magnetic fields. They hope that the technique might one day be developed into a fertility treatment for men with low sperm motility.
The miniature titanium- and nickel-coated polymer helices were just big enough to fit around the tail of a single sperm cell. A rotating magnetic field made the metal helices spin, propelling them forward. By adjusting the orientation of the magnetic field, the researchers were able to direct one of these micromotors to latch onto a non-swimming sperm, driving it forwards towards an egg. Once it reached the egg, the micromotor was then released.
Low sperm count or poor sperm quality is the cause of infertility for around 20 percent of couples who are having difficulty conceiving. Intrauterine insemination, in which sperm are injected directly in the uterus, has a relatively low success rate per cycle; IVF fares better but is more invasive and expensive, requiring eggs to be extracted and then embryos implanted.
While this technique is a long way from clinical testing, the researchers hope that one day their so-called 'spermbots' could instead deliver a single healthy sperm directly to an egg inside a woman's body, using an MRI, magnetic resonance imaging, machine to direct it to exactly the right spot.