Scientists from Columbia University, Arizona State University, the University of Michigan, and the California Institute of Technology (Caltech) have created a robot that’s just 4 nanometers wide. And no, it doesn’t have flashing lights, video cameras or wheels. It does, however, have four legs, and the ability to start, move, turn, and stop. Descendants of the molecular nanobot, or “spider,” could someday be used to treat diseases such as cancer or diabetes.
The team built the spider by starting with a protein called streptavidin, that conveniently has four symmetrically-placed binding pockets for a chemical called biotin. The legs were made from four strands of biotin-labeled DNA, which were bound to the pockets. Three of the legs were made from enzymatic DNA, which is a type that binds to and then dissociates (cuts away) from other particular sequences of DNA. Its fourth leg was made from what the researchers call a “start strand” of DNA - it keeps the spider tethered to its starting site, until it’s released.