A new system devised by MIT researchers could provide a novel method for moving tiny objects inside a microchip, for biomedical screening or the detection of trace elements for pollution monitoring or security screening, or might someday be developed for use in medical diagnostics, by allowing controlled delivery of particles inside the body to specifically targeted locations.

The researchers devised a system that uses tiny beads made of polymers with specks of magnetic material in them. With these beads suspended in a liquid, they applied a rotating magnetic field, which caused the beads to spontaneously form short chains that began spinning, creating currents that could then carry along surrounding particles — even particles as much as 100 times larger than the beads themselves.

The new method could provide a simpler, less-expensive alternative to present microfluidic devices, which require precisely made channels, valves and pumps created using microchip manufacturing methods, to control the movement of fluids through them.