Cyano-substituted oligo (p-phenylene vinylene)-Based supramolecular nanostructure capable of detecting a specific enzyme

We report on the cyano-OPV (1) possessing a trimethyl-locked quinone group exhibited monomer and aggregate emissions with distinct colors determined by the ratio of tetrahydrofuran/water (THF/H2O), thereby suggesting a strong dependence on the polarity of the solvent. In contrast, cyano-OPV (2) possessing an amine group exhibited a yellow emission in the THF/H2O mixture, regardless of the ratio of solvents used, which is indicative of the formation of a supramolecular aggregate by π-π stacking and intermolecular hydrogen-bonds. This further supports the AFM and DLS observations in which 1 and 2 are shown to be comprised of spherical nanoparticles with mean diameters of ~300 nm. The supramolecular aggregate 2 is generated by a cooperative pathway involving a nucleation-elongation mechanism. More interestingly, 1 was converted to 2 in the presence of NQO1 and NADPH, in a mixture of THF/H2O (20:80 v/v) at 37 °C, which lead to the formation of the supramolecular aggregate with its characteristic yellow emission.