Profile: Nanoprobes, Inc. develops sensitive reagents and technology for detecting biological molecules. We specialize in immunogold labeling and immunoassay tests. We use Nanogold®-Streptavidin for ultrasensitive in situ hybridization to localize viral DNA and RNA in carcinoma specimens. Our unique gold labeling technology uses chemically cross-linked metal clusters and nanoparticles as labels. Our gold labels are uncharged molecules which are cross-linked to specific sites on biomolecules. Our labels can be attached to any molecule with a reactive group such as proteins, peptides, oligonucleotides, small molecules and lipids, for detection and localization. Our FluoroNanogold probes combine Nanogold® and fluorescein into a single probe for imaging a specimen both by fluorescence and electron microscopy. We also offer a complete line of 3, 5, 10, 15 & 30 nm colloidal gold probes, and a line of silver enhancement & negative staining reagents.