FRAMINGHAM (10/21/2003) - Researchers at the Centre de Physique Moléculaire Optique et Hertzienne (CPMOH) have developed a new technique to visualize miniscule amounts of different proteins in cells. The researchers use gold nanoparticles (10 nanometers across) to label different proteins in a cell. The technique produces a 3-D map of cell membrane proteins that can be used to identify the presence of very small amounts of immunological or other types of proteins. In a recent paper submitted to , the group says that its all-optical protein detection method, which is called photothermal interference contrast, yields better results than previous attempts that relied on fluorescent markers. The researchers believe this gold nanoparticle technique could be applied to DNA and protein chips to improve detection.