Silver 'Mirrors' Reflect Single Molecule's Wild Dance

Researchers at the Massachusetts Institute of Technology have discovered a way to identify the structure of a single molecule, knowledge that could prove invaluable for biomedical applications such as human gene analysis. The method, surface-enhanced Raman scattering, has been used for decades, but the MIT researchers added a twist: silver particles about 100 nm across. They dropped the particles into a solution and added a few dye molecules, which attached themselves to the silver particles. An 830-nm Ti:sapphire laser beam set a single dye molecule's atoms vibrating. The molecule's Raman-shifted reflections revealed the arrangement of chemical bonds that hold it together.