Lego robot used to make DNA structures for tiny machines more quickly

A robot made of Lego can quickly perform an important step for creating machines made of DNA. "This started as a final project in an undergraduate lab course," says Rizal Hariadi at Arizona State University, who tasked his class with building tools using "frugal science". The robot that one group of students built has proved particularly useful and resembles a single arm topped with a holder for cylindrical tubes. It performs a procedure to mix the liquid contents of the tubes, first tilting the tubes from vertical to horizontal, then rapidly spinning them around. This creates a single liquid with a density that uniformly decreases from the bottom to the top.