Researchers at Phillips Innovative Technologies in Hamburg, Germany have created a way to manipulate each robot in a swarm individually and assign them specific tasks using magnetic fields. The scientists presented their findings on Feb. 15th in the Journal Science Robotics.

Previously, it was difficult to precisely control the microscopic devices because they would all behave the same way when controlled by the same magnetic field. "Our method may enable complex manipulations inside the human body," study lead author Jürgen Rahmer told Live Science.

Scientists now want to use the robotic swarm to deliver cancer-killing radioactive "seeds" specifically to tumors within the body. Treating cancer this way could spare healthy tissue and reduce harmful side effects. It could also be used to create medical implants that change over time as a person heals, researchers said.