A team of engineers from the U.S. and South Korea has developed what is believed to be the smallest man-made pump ever built, powered by a glass electrode. The pump is about the same size as a red blood corpuscle.

The pump works by electroosmosis, in which electricity pushes the fluids from one end of the pump to the other. The heart of the pump measures only four micrometers across, and the pump is capable of controlling a flow rate of one femtoliter per second.

Applications include delivering drugs to an individual cell and taking fluid samples from single cells. The glass electrodes could also be integrated into other nanoscale devices.