Compact Halo-Ligand-Conjugated Quantum Dots for Multicolored Single-Molecule Imaging of Overcrowding GPCR Proteins on Cell Membranes.

To detect single molecules within the optical diffraction limit (< ca. 200 nm), a multicolored imaging technique is developed using Halo-ligand conjugated quantum dots (Halo-QDs; <6 nm in diameter). Using three types of Halo-QDs, multicolored single-molecule fluorescence imaging of GPCR proteins in Dictyostelium cells is achieved.