Now, microrobots inspired by sperm

Researchers have developed sperm-inspired microrobots, which can be controlled by oscillating weak magnetic fields.

The 322 micron-long robots consist solely of a head coated in a thick cobalt-nickel layer and an uncoated tail.

Researhers have said that this type of robots can help in many avenues such as targeted drug delivery, in vitro fertilization, cell sorting and cleaning of clogged arteries, among others.

When the robot is subjected to an oscillating field of less than five millitesla - about the strength of a decorative refrigerator magnet - it experiences a magnetic torque on its head, which causes its flagellum to oscillate and propel it forward. The researchers are then able to steer the robot by directing the magnetic field lines towards a reference point.

Islam Khalil designed the MagnetoSperm microrobots along with Sarthak Misra and colleagues at MIRA-Institute for Biomedical Technology and Technical Medicine at the University of Twente.

"As technology progresses and many products get smaller, it becomes difficult to assemble objects on nano- and micro-scales," Dr. Islam Khalil, an assistant professor of the German University in Cairo, said. "MagnetoSperm can be used to manipulate and assemble objects at these scales using an external source of magnetic field to control its motion."

In addition to nano-assembly, the radical downsizing afforded by the offloading of power and navigation systems opens up a wide range of biomedical tasks that MagnetoSperm can perform, Khalil said.

The microrobot was made by spin-coating onto a silicon support wafer a five-micron layer of SU-8, a polymer chosen for its ease of fabrication and mechanical stability. The cobalt-nickel layer was then added to the head by use of electron beam evaporation.

The study has been published in the journal Applied Physics Letters.