Preparation and application of water-soluble quantum dots

Water-soluble quantum dots (QDs) with high photo-luminescence quantum efficiency have shown great potentials in photonic crystals, thin-film light-emitting devices, and especially biological labels. Since QDs are bright, photo-stable and have a broad excitation spectrum but a narrow emission at wavelengths controllable by the size and the composition of the material, they allow for efficient multicolor imaging of biological samples and should be especially useful for fluorescence imaging in living tissues, where signals can be obscured by scattering and competing intrinsic emissions. QDs have become one of the most attractive areas of current research and a new kind of interdisciplinary science. Recently, valuable progress has been achieved in water-soluble QDs as fluorescent biological labels. In this paper, structural and optical properties of QDs are introduced, recent developments with preparation and applications of water-soluble QDs are reviewed, especially as fluorescent probes in biology and biomedicine.