Multicolor coding of cells with cationic peptide coated quantum dots

Quantum dots are a new class of fluorophores, whose more prominent characteristics include size-tunable, narrow, fluorescence emission bands and broad overlapping excitation spectra of multiple color dots. Here, we present an efficient, versatile, and gentle approach for intracellular delivery of quantum dots that is easily extended to multicolor optical coding of mammalian cells. In this method, a nine residue biotinylated L-arginine peptide is used to enhance delivery of streptavidin conjugated quantum dots into mammalian cells.