The gold nanoparticles are arranged by custom DNA molecules to produce colors.
Thanks to a method developed by scientists at Aalto University, Finland, a new image display technology could be brought to life.
Produce colors from gold
The proposed technique uses gold nanocylinders suspended in a gel. The gel only transmits certain colors when illuminated with polarized light, and the color depends on the orientation of the gold nanocylinders. A collaboration led by the research groups of Anton Kuzyk and Juho Pokki used DNA molecules to control the orientation of the gold nanocylinders in the gel.
“DNA is not only a carrier of information, it can also be a building block. We designed DNA molecules to have a certain melting temperature, so we could basically program the material.”says Aalto’s doctoral candidate Joonas Ryssy, lead author of the study. When the gel is heated beyond melting temperature, the DNA molecules loosen their grip and the gold nanocylinders change orientation. When the temperature drops, they harden again and the nanoparticles return to their original position.
The researchers tested several custom DNA molecules with different melting temperatures to find the best answer. With the current system, the technology can produce red and green lights. Once further work makes blue light transmission possible, this approach could be used to generate any color by mixing red, green, and blue.
“The whole concept, the underlying philosophy behind the work, is to use simple methods, simple materials and simple tools to generate colors in a dynamic and reversible way,” says Sesha Manuguri, a postdoctoral researcher at Aalto who led the study. For Manuguri, part of the elegance of the technique is that the gold nanocylinders accomplish both necessary tasks. “Gold nanorods heat up when ignited, heating the gel, and they are also responsible for color formation. So you don’t need separate heating elements.”commented.
With further development, this approach could be used to produce color on different types of screens. Because all the materials are biocompatible, this could be ideal for displays on wearable sensor devices, but the technology could also be used on billboards or other displays.
“We’ve done the basic science to bring these building blocks together in a symbiotic way to create something functional. Now it’s up to engineers to explore what kinds of devices could be made.”Manuguri says.
Formerly, popular belief said that there was a pot of gold at the end of the rainbow, but the new technology presented here is rethinking that idea: using gold particles to make colors. Based on these findings, the method developed at Aalto University could bring to life a new visualization technology.
