Anyone who ever has worked in a laboratory has seen them: magnetic stirrers that rotate magnetic stir bars in liquids to mix them.

• Position: SCIENCE SCENE - Brief article

Anyone who ever has worked in a laboratory has seen them: magnetic stirrers that rotate magnetic stir bars in liquids to mix them. The stir bars come in many different forms--now including nanometer-sized. In the journal Angewandte Chemie, researchers from Singapore have introduced chains made of 40 nm iron oxide particles that act as the world's smallest magnetic stir bars, effectively stirring picoliter-sized drops of emulsion with a...