It's difficult to make nanoscale chemical reactions that are powerful enough to move something in a specific direction. Scientists are studying several possibilities, including "fuel molecules" that decompose to move an object forward. Bipolar electrochemistry is a new method that could be simpler and easier to control. It involves exposing a metal material to an electrical field so that it has a positive charge at one end and a negative charge at the other. According to CNRS, the French National Center for Scientific Research, this enables chemical reactions to occur on both ends of an object — one end is oxidized and dissolves, and deposited at the other end. A paper describing the method appears in the Journal of the American Chemical Society.