Therapy Robots a Step Closer to Reality

In tests, a swarm of robots measuring a few millionths of a meter long — about the size of a blood cell — were guided magnetically to sites in the stomach of rats. The robots were manufactured by coating tiny algae with magnetic particles. They could be tracked in tissue close to the skin's surface by imaging the algae's natural fluorescence, and in hard-to-reach deeper tissue by magnetic resonance imaging (MRI).