Magnetic nanocubes self-assemble into spirals


© AAAS/Science

Scientists have been coaxing nano-sized cubes of magnetite (Fe3O4) into larger, more complex structures like helices without using a template by exposing them to a magnetic field.

A team led by Rafal Klajn at the Weizmann Institute of Science in Israel found that by varying the density of the cubes and the size and direction of the magnetic field they can control the kind of structure the cubes self-assemble into, which depends on the interplay between intermolecular forces and magnetic interactions. Under an increasing magnetic field the nanocubes line up to make a ‘belt’, while under a constant magnetic field at high density they curl round and form a helix. Single helices tend to clump together to make double helices (like the rope-like structure shown above) or even triple helices.

Although at the moment there is no obvious use for the structures, the team say they could have interesting magnetic properties. They are now exploring the effects of using other magnetic nanomaterials, such as nickel or iron nanoparticles, and decorating the nanocube surfaces with functional ligands to see what other shapes can be made.

Related Content

The golden helix

10 October 2012 Premium contentFeature

news image

Fifty years after the Nobel prize was awarded for the structure of DNA, Mike Sutton looks back at how it all came about

Electric switch makes helix change hands

3 September 2015 Research

news image

Computational model predicts that external electric fields can reorientate helices by breaking and reforming hydrogen bonds

Most Commented

Chlorinated compounds form in tea and coffee

24 November 2015 Research

news image

Treated water reacts with organics to form disinfection byproducts

Brazilian mine disaster releases dangerous metals

21 November 2015 News and Analysis

news image

Irreversible negative human health and environmental effects could result from Brazilian mine’s dam collapse