Abstract: The present invention relates to nanoscale polymer dots (Pdots) that include strongly light absorbing semiconducting polymer nanoparticles doped with near-IR emitting dyes. The polymer functions as an antenna and transfers the excitation energy to the doped near-IR emitting dye molecules, which function as the emitting entity. The resulting Pdots feature very bright near-IR emission with emission wavelength tunability, high water solubility, and stability in biological solutions.

Abstract: New phosphoramidite Cy5 derivatives can be used in automated DNA synthesis, allowing the labeling of DNA sequences with a wider array of chromophores than are presently commercially available. In addition to varying dye hydrophobicity/hydrophilicity, the 5,5?-substituents (including hexyloxy, triethyleneglycol monomethyl ether, tert-butyl, and chloro groups) can modulate electron donating/withdrawing character while also tuning resulting absorption and emission properties. Modification of the Cy5 periphery enables the tuning of photophysical properties, such as absorption and emission maxima, fluorescence quantum yield, and fluorescence lifetime.