TECHNOLOGY: Nanoshells

At the level of nanometers, the world behaves under slightly different laws of physics from those we are used to. This can be illustrated with regard to color, the wavelength of light reflected by an object. A red piece of paper will remain red after being cut into smaller and smaller pieces until those pieces reach the level of nanometers. At this point, the interactions between “red paper” molecules begin undergo alterations which may affect the light reflected by the particles and change their perceived color.

Nanoshells are spherical nanoparticles with a silica core surrounded by a gold coat ranging from 5-20nm in thickness. By altering the thickness of the gold coat, researchers take advantage of the special laws obeyed on the nano level to change the spectrum of light absorbed most strongly by the shells. Moreover, shining light within this absorption spectra on these shells causes them to heat up and kill surrounding tissue. This phenomenon is useful for eliminating tumor cells in cancer.

The small size of these nanoshells makes it easy for researchers to administer the shells through bloodstream into the tissue of interest. Researchers may coat the nanoshells with anitbodies designed to localize to tumor cells and tune the absorption spectra of the shells to match the light most strongly absorbed in these tissues. A lab in Rice University led by Dr. Jennifer West has recently shown these nanoshells to be useful in eliminating tumor cells in (here). Nanoshells may also be tuned to scatter certain wavelengths of light. This has proven useful for imaging tumor cells and may have other uses for optical imaging as well.