Silver nanoparticles have extraordinary efficiency in absorbing and scattering light and can be used for labeling and imaging. The high scattering cross-section of nanoparticles allows individual silver nanoparticles to be imaged under a dark-field microscope or hyperspectral imaging system. By coupling antibodies to their surfaces, silver nanoparticles can target specific cells or cellular components. The attachment of targeted molecules to the surface can be accomplished by adsorption on the surface of nanoparticles, covalent coupling or physical adsorption.