Hollow Gold Nanospheres Are Now Possible

Researchers at the University of California in Santa Cruz (UCSC) have developed a very complex type of microscopic objects, one that is entirely made of gold and is shaped like a sphere. Already, the innovation has proven to have significant applications in treating some types of cancer, but also in advancing several researches in chemistry.

The nanospheres have very distinct and unusual properties, in that they can be constructed to absorb light strongly, narrowly, or even tunably. That is to say, the distance between them can be modified in the “growing” process, so that the end-result would consist of tighter-packed objects on the same amount of space. The formations could be successfully used to target tumors in the photothermal cancer therapy.

“What makes this structure special is the combination of the spherical shape, the small size, and the strong absorption in visible and near infrared light. The absorption is not only strong, it is also narrow and tunable. All of these properties are important for cancer treatment,” UCSC professor of chemistry and biochemistry Jin Zhang, who presented his latest results yesterday, March 22nd, at the annual meeting of the American Chemical Society, held in Salt Lake City, the US, explained.

“The heat that kills the cancer cells depends on light absorption by the metal nanoparticles, so more efficient absorption of the light is better. The hollow gold nanospheres were 50 times more effective than solid gold nanoparticles for light absorption in the near-infrared. It is a unique structure that offers true advantages over other nanostructures, so it has a lot of potential,” Zhang said.

The researcher's main motif to start working on these nanospheres several years ago was to help create better surface-enhanced Raman scattering (SERS) devices. SERS is a technique that allows for the viewing of microscopic particles and other biological functions in great detail and resolution.

“This process is able to produce SERS-active nanoparticles that are significantly smaller than traditional nanoparticle structures used for SERS, providing a sensor element that can be more easily incorporated into cells for localized intracellular measurements,” Adam Schwartzberg, who is a graduate student in Zhang's lab, pinpoints in a 2006 study.