Many consider enzymes the workhorses of biochemistry (move over, mitochondria)—catalyzing reactions, breaking down substrates, keeping the machinery of life humming along. But a growing number of researchers are re-envisioning what enzymes can do. Instead of facilitating chemistry, what if enzymes could steer and even guide tiny robots to a tumor? 

That’s exactly what’s happening in the rapidly expanding field of enzyme-powered microscopic robots (a.k.a “microrobots”). Microrobots are tiny, engineered devices—often smaller than the width of a human hair—built to perform tasks inside the body that would be difficult or impossible at a larger scale, like delivering drugs to a specific tissue. A recent paper published in Nature Nanotechnology by a team of researchers at California Institute of Technology and the University of Southern California offers a particularly elegant example that we highlight below¹.