'Robotic sperm' controlled with magnets

Engineers at the University of Twente in the Netherlands have managed to build sperm-like robots, which can be controlled with magnets.

The design is fairly simple, with a metal-coated head and a flexible body, but are around six-times larger than the size of human sperm. By using a magnetic field, which is about as strong as regular fridge magnets, the team can make the sperm "swim" forward and control its direction.

Dr Sarthak Misra, a robotics engineer at the University of Twente, said: "We have built a biologically inspired micro-robot that looks like a sperm cell but is completely fabricated in the lab." 

The team hope their research, which was published in the journal Applied Physics Letters, will be able to be used in medical and manufacturing applications.

Dr Misra and his team demonstrated the microrobots' ability to swim forward and that their movement can be controlled, which in turn allows for the targeted release of drugs. This could be used in IVF treatments, a procedure where very precise locations must be reached for it to be successful.

The team will now conduct further experiments in a bid to make MagnetoSperm even smaller and faster, and try to precisely control a swarm of MagnetoSperms.

Sperm use a whip-like "flagellum" to travel through fluid and the new robotic sperm are made from a strong but flexible polymer, with a metal layer painted onto its head using a technique called electron beam evaporation.

It is this metal element that allows the engineers to control the direction in which the sperm travels in when the device is placed into a moving field, which is produced by the coils of an electromagnet.

Dr Misra and his colleagues found that by adjusting the magnetic field changes with a computer, they could precisely determine where the robotic sperm would go. 

However, for its use in medical applications, the team would need to analyse their creation and the technique in more complicated environments.