A symbiosis: tracking cell signaling with expression probes, quantum dots and a programmable array microscope (PAM)

Quantum dots (QDs) are colloidal inorganic semiconductor nanocrystals composed typically of a CdSe, CdS or CdTe core and a ZnS shell. There are many advantages in the use of QDs as fluorophores: they can be excited over a broad spectral range and they have narrow emission bands that can be tuned from ultraviolet to infrared by adjusting size and composition. Their bright emission fluorescence and resistance to photobleaching make QDs ideal for single-particle detection and permit imaging over prolonged time periods. Because of these advantages, QDs are finding increasing use in in vivo and in vitro studies [1].