DNA Robots Built for Random Walks, Deliberate Sorts

While its feet may wander aimlessly, its hand won’t pick up just anything. Neither will it release its finds willy nilly. “It” is a molecular robot, a single-stranded DNA with one leg and two foot domains for walking, and one arm and one hand domain for picking up and dropping off cargos. And it doesn’t necessarily walk alone. It may mill about a two-dimensional surface with its peers, who may have their preferences for what they pick up, and where they release their find