Sperm-driven bio-bots controlled by magnets

Researchers in Germany have discovered a novel way to influence the direction of travel of sperm.

Professor Oliver Schmidt and colleagues at the Institute for Integrative Nanosciences in Dresden used magnetic nanotubes powered by bull semen to create possibly the first ever sperm-driven biological robots, or 'biobots'.

To make the biobots, the team poured 50-micron-long nanotubes made of iron and titanium into a solution containing bull semen. The nanotubes are narrower at the front than at the back so when a sperm swims inside, its head becomes trapped but its tail is free to power the biobot forward.

The researchers were able to influence the sperm's direction of travel with weak magnetic fields, much like lining up the needle of a compass.

The biobots may ultimately have applications in drug delivery. Professor Schmidt told New Scientist that sperm cells are an attractive option in this field because they are harmless to the human body, do not require an external power source, and can swim through viscous liquids.

Speaking to the Daily Mail, Professor Schmidt said that an application in fertility treatment was 'compelling but is still far from being realised'.

However, he added that there was 'no reason why this technique should not work for human sperm cells as well'.

'One possible way might therefore be to capture single sperm cells in vitro, transfer the sperm-driven robots into the uterus and guide them magnetically towards the egg cell location', he told the paper.

The study was published in the journal Advanced Materials.