Busy Beads: Magnetic dust takes droplets for a ride

While many chemists are working to reduce the elements of a chemistry lab to a single chip replete with miniature pumps, channels, and valves, others are striving for a simpler route to miniaturization. Rather than shuttling liquids through complex microfluidic plumbing, some scientists have imagined doing all their chemistry by rolling drops of liquid from one chip location to the next.