Nanoprobes Inc. develops sensitive reagents and technology for detecting biological molecules. The firm's unique gold labeling technology uses chemically cross-linked metal clusters and nanoparticles as labels. Unlike conventional immunogold probes, in which colloidal gold particles are electrostatically adsorbed to antibodies and proteins, the firm's gold labels are uncharged molecules that are cross-linked to specific sites on biomolecules. This gives the firm's probes a range and versatility which is not available with colloidal gold. Labels can be attached to any molecule with a reactive group -- proteins, peptides, oligonucleotides, small molecules and lipids -- for detection and localization.