Optical analysis of beads encoded with quantum dots coated with a cationic polymer

Quantum dots are incorporated onto small beads made or various materials thanks to the versatile layer-by-layer method. The high contrast, tri-color gradient TEM image of a bead emphasizes quantum dots in red-yellow spots. Below, quantum dot coated magnetic beads demonstrate bimodality with their bright fluorescence and alignment along field lines. An hyperspectral imaging inspired technique allowed faster statistical characterization of optically coded beads on a setup typical of biological experiments. [GRAPHICS]