Image copyright I Khalil, S Misra Image caption Sperm-inspired robots "swim" when they are made to wiggle by a moving magnetic field 
 
 Engineers have built a sperm-like robot that they can control with magnets. 
 
 The simple design has a metal-coated head and a flexible body about six times longer than a human sperm. 
 
 Using a magnetic field no stronger than a fridge magnet, the team made the robot "swim" forward and steered it towards a fixed point. 
 
 They hope the findings, published in the journal Applied Physics Letters, will be useful in medical and manufacturing applications. 
 
 "We have built a biologically inspired micro-robot that looks like a sperm cell but is completely fabricated in the lab," said Dr Sarthak Misra, a robotics engineer at the University of Twente in the Netherlands. 
 
 Sperm, like some bacteria, use a whip-like "flagellum" to propel themselves through fluid. 
 
 Other studies of this process have included coupling a magnetic tail to a red blood cell, or controlling real sperm by steering them in metal microtubes. 
 
 The new gadget is made from a strong but flexible polymer, with a metal layer painted onto its head using a technique called electron beam evaporation. 
 
 That metal element is forced in different directions when the device is placed into a moving field, produced by the coils of an electromagnet. 
 
 Precise navigation 
 
 "The magnetic head is used to orient it in a certain direction and then, just by flapping its tail, it starts to move forward," Dr Misra told the BBC. "The flapping happens because we change the current in the coils." 
 
 Image copyright I Khalil, S Misra Image caption The simple robots consist of a flexible tail and a head with an added metallic layer 
 
 For its size, the robot can hardly compete with its biological inspiration for pace: it wiggles along at up to 0.5 body lengths per second, whereas a human sperm can cover several times its body length in that time. 
 
 Importantly, however, Dr Misra and his colleagues also showed that they could steer the robot with some precision. By adjusting the magnetic field changes with a computer, they navigated their creation towards a fixed point. 
 
 This means the little robots could be useful for positioning materials in nanomanufacturing, or for medical purposes. "It opens up a lot of applications, from targeted drug delivery to in vitro fertilisation - where you want to reach precise locations," Dr Misra said. 
 
 For these ideas to work, the researchers need to test the technique in more complicated environments. They are moving on to those experiments, as well as working on making their "MagnetoSperm" smaller and faster. 
 
 Image copyright SPL Image caption Human sperm are another six times smaller than the tiny robots that were modelled on them 
 
 Dr Matthew Baker, who studies molecular motors at the Victor Chang Cardiac Research Institute in Sydney, told BBC News the work was "very cool" but commented that the tiny contraptions are not robots in the sense that most of us would imagine. 
 
 "It's just a piece of metal and it's the field that's doing the hard work," Dr Baker explained. "The clever part is the oscillating, small, tunable magnetic field." 
 
 This out-sourcing of power and navigation is what allows the gadget to be so small, according to the new study's first author Dr Islam Khalil. "As technology progresses and many products get smaller, it becomes difficult to assemble objects on nano- and micro-scales," he said in a press statement. 
 
 "MagnetoSperm can be used to manipulate and assemble objects at these scales, using an external source of magnetic field to control its motion." ||||| Just when you thought you'd seen every kind of robot there is, researchers develop bots inspired by sperm. 
 
 The tiny robots mimic the shape and movement of sperm cells and can be steered using magnetic fields. Dubbed "MagnetoSperm," the robots could be useful for administering medicine or carrying out in vitro fertilization, researchers say. 
 
 "Nature has designed efficient tools for locomotion at micro scales," study leader Sarthak Misra, a mechanical engineer at the University of Twente in the Netherlands, said in a statement. [The 6 Strangest Robots Ever Created] 
 
 Improvements in technology are making many products smaller, but it is difficult to assemble objects on the nanoscale (a billionth of a meter) or microscale (a millionth of a meter), the researchers said. 
 
 Misra and a team of scientists at his university and the German University in Cairo design robots inspired by nature or ones that use living microorganisms, such as magnetically propelled bacteria and sperm cells, for performing complex tasks on small scales. 
 
 In a new study, published today (June 2) in the journal Applied Physics Letters, the researchers created 322 1-micron-long (about 10 times the width of a human hair) robots with heads thickly coated with cobalt-nickel, but uncoated tails. 
 
 When the sperm bots were exposed to an oscillating magnetic field with a strength less than that of a refrigerator magnet, the force caused the sperm bots' heads to rotate and their tails to move back and forth, pushing the bots forward. The researchers steered the robots by aiming the magnetic field toward a reference point. 
 
 The magnetic swimmers could be used for a number of biomedical applications, including drug administration, in vitro fertilization and the cleaning of clogged arteries, the researchers said. 
 
 The robots were assembled by a method known as spin coating, in which a thin polymer film is deposited onto a silicon wafer. The researchers chose a polymer that was simple to fabricate and wouldn't break down easily. They then used an electron beam to deposit the cobalt-nickel layer onto the heads of the bots. 
 
 The researchers plan to scale down their robots to an even smaller size and develop a magnetic nanofiber that could be used for the tails. 
 
 Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.
– Technophobes may be alarmed to learn that new sperm-like robots could soon be performing many activities—including fertilizing human eggs. Researchers say the tiny bots, dubbed "MagnetoSperm," were inspired by the shape and movement of sperm cells and can "swim" to their target with incredible accuracy, LiveScience reports. They believe the sperm bots could be useful in nanomanufacturing as well as for medical uses including unclogging arteries, drug administration, and in vitro fertilization. The robots have a metal head and a body of flexible polymer, and are steered through a field produced by electromagnetic coils. "The magnetic head is used to orient it in a certain direction and then, just by flapping its tail, it starts to move forward," the lead researcher explains to the BBC. "The flapping happens because we change the current in the coils," he says, predicting that the tiny bots will prove useful where it is necessary to reach "precise locations." The bots are still a lot slower—and around six times bigger—than human sperm, but the MagnetoSperm team says it is working on creating smaller, faster versions. (Meanwhile, scientists have recently found the world's oldest sperm.)