Controllable cy3-MTC-dye aggregates and its applications served as a chemosensor

•H- and J-aggregates of MTC could be conversed mutually.•J- or H-aggregates could be converted to monomeric states by biomolecules.•MTC could be used as a chemosensor to detect Na+/K+ ratio or Pb2+ concentration.

The cyanine dyes are among the oldest classes of synthetic compounds but continue to find applications in a variety of fields. Compared to other organic molecules, diverse and controlled aggregate property is one most canonic feature of the cyanine dyes. With a primary focus on our own work, here we chose 3,3′-di(3-sulfopropyl)-4,5,4′,5′-dibenzo-9-methyl-thiacarbo-cyanine triethylammonium salt as one model to discuss its controllable aggregates and its applications served as a chemosensor. Its H- and J-aggregates could be conversed mutually by the regulation of metal-salts or temperature or small peptides, presenting varied characteristic absorption spectra. And its J- or H-aggregates could be destroyed and converted to monomeric states, respectively by human serum albumin or G-quadruplex DNA. Furthermore, it was sensitive to the subtle conformer of G-quadruplex, and thus applied in detecting the Na+/K+ ratio or Pb2+ concentration in the solution samples as a chemosensor.

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