Scientists at the University of California have come up with a nifty new way to utilize nanoparticles of gold. A solution of gold particles embedded in a polymer film creates a bright blue color, which turns red after pressure is applied on the film. The color shift correlates with the amount of pressure used — blue turns purple after moderate impact and red with a hard hit. This nuanced response yields information about different pressure levels the gold film encounters. The possibilities seem limitless, from sports to scientific studies to fashion.
Interestingly enough, nanogold was used hundreds of years ago to produce vivid colors. Medieval masters of producing stained glass windows used nanoparticles of gold to achieve bright red colors and silver nanoparticles to create an intense yellow.
Going back even further, Romans created the legendary Lycurgus Cup 1,600 years ago using nanoparticles of gold and silver. Metal particles smaller than 50 nanometer gave the chalice a unique property: It changed color depending on what kind of liquid was poured into it.
There has been some speculation over whether the color changes on the cup might have been able to signal presence of certain types of poisons or pathogens. However, the vessel is so valuable that using it in laboratory tests has been ruled out.
Obviously, Romans did not understand the theoretical underpinnings of nanoparticles. It’s not clear how they stumbled onto creating and using them in such a striking manner.
Over the past years, nanogold has been a focus of feverish interest in the biomedical research community. It is expected to become an important tool in treating cancer and Alzheimer’s, thanks to nanogold’s special optical properties that allow doctors to visualize the location and concentration of proteins it has been attached to.
Of course, we will now all be waiting for the most important application yet — smartphone covers that show just how tight your grip has been following a tense phone call.