Carestream Molecular Imaging has added nanosphere conjugates labeled with streptavidin to its Kodak X-Sight family. These optical molecular imaging agents enable the detection of biotinylated probes in fluorescent molecular biology research applications. Fully biocompatible, they are suitable for in vivo and in vitro applications because they provide high photostability and brightness. They are offered in four wavelengths, ranging from the UV to the near-IR. Although the agents are optimized for Kodak imaging systems, they are compatible also with other commercially available systems.