Stirring in suspension : nanometer-sized magnetic stir bars

Abstract

Stirred, not shaken: Single-line chains of 40 nm Fe3O4 nanoparticles can be used as the world's smallest magnetic stir bars. Their synthesis is facile and scalable. They can be introduced into picoliter emulsion droplets and turned effectively using a commercial magnetic stir plate. Because of their small size, they can resist sedimentation under gravitational and magnetic forces, thus allowing them to remain suspended and stir all parts of the solution.