Gold nanoparticles produce colours

DNA molecules are used to arrange the gold nanoparticles.

A technique to produce colours from gold nanoparticles that are arranged by custom DNA molecules has been developed at Aalto University, Finland.

The technique uses gold nanocylinders suspended in a gel which only transmits certain colours when lit by polarised light, with the colour depending on the orientation of the nanocylinders.

The research team say that the DNA molecules have been designed with a certain melting temperature and when the gel melts the molecules loosen and the nanocylinders change direction. As the temperature drops the moloecules tighten up and the nanoparticles return to their original position.

Currently, the system produces red and green light. The gold nanrods heat the gel and also are responsible for colour formation so seperate heating elements are not needed.