Modern chip fabrication techniques, and an idea initially proposed by Nobel physicist Richard Feynman, have led to the development of a device that can separate membrane-attached proteins in their native state (Science 285, 1046–1048, 1999). By attaching a lipid membrane to the surface of a chip, then erecting microscopic physical barriers on the chip in a repeating pattern, researchers have created a two-dimensional "Brownian ratchet" that sorts membrane proteins. The device works by applying an electric field to proteins introduced at one corner of the chip, which while migrating through the electric field make random lateral movement due to Brownian forces. When a protein encounters one of the diagonal barriers, it is shifted a short distance across the electric field before continuing its journey. Like game pieces in a pachinko machine, proteins are sent along different paths by the barriers. As the proteins can travel through the ratchet in their native membrane-associated state, the technique may simplify many types of biochemical analysis. "Molecules in a ratchet-type device can also be used to measure alterations in properties associated with binding [and] clustering," as clustered proteins would migrate differently, explains Steven Boxer, senior author on the paper.