You鈥檇 need your glasses on to play this version of Pac-Man. Tiny metal robots can plot their own route around a maze modelled on the iconic video game. Similar devices could one day be used to travel around the body, delivering drugs or performing surgery.
Sarthak Misra from the University of Twente, the Netherlands, and colleagues created four different types of micro-gripper robots, with the smallest being just 100 micrometres long. The biggest was still less than one millimetre. The bots are made from metal and controlled using magnetic fields and have have pincers that fold when they聽get warmer than聽body temperature. In tests, the team showed how the robots could be manoeuvred around a basin of water using 6 electromagnetic coils.
But to work inside the human body the robots would need to be able to plot their own route. To see how precisely they could be controlled, the team created a series of virtual Pac-Man mazes, each one designed to be 20 times bigger than each robot.
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Just like in the classic game, the maze was haunted by virtual ghosts, which were programmed to chase down the robots, switching between 鈥榗hase鈥� mode, where they estimated where the robots might be, and 鈥榮catter鈥� mode where they rushed towards the centre of the maze. The set-up simulated how the robots could be guided by an algorithm that tried to plot a ghost-free route to a set destination point.
Get a grip
The team also tested how good the real robot鈥檚 grips were, using them to try to grab a chunk of mozzarella cheese with the pincers that closed on the application of a magnet. Some of the designs which had 6 pincers were good at cutting tiny pieces of the cheese, suggesting they might be handy when excising tissue, for example. And the team estimates that three of the designs would be able to travel relatively easily against聽normal blood flow, making them far more useful in medical applications.
Misra says that the work is important because it showed how such mini-robots could move to a target location, despite obstacles being in its path. 鈥淚n the long term we feel such miniaturised grippers could be used as micro-robots for applications within minimally invasive surgery, such as taking biopsies,鈥� he says.
