Researchers at MIT and other institutions have achieved a long-sought goal of creating particles that can emit a colorful fluorescent glow in a biological environment, and that could be precisely manipulated into position within living cells. The new technology could make it possible to track the position of the nanoparticles as they move within the body or inside a cell. At the same time, the nanoparticles could be manipulated precisely by applying a magnetic field to pull them along. The particles could have a coating of a bioreactive substance that could seek out and bind with particular molecules within the body, such as markers for tumor cells or other disease agents. Previous efforts were unable to produce particles of uniform and predictable size, which could also be an essential property for diagnostic or therapeutic applications. This video shows how supernanoparticles are made to glow and manipulated with magnets inside a cancer cell.