Self-assembly of J-aggregate nanotubes and their applications for sensing dopamine.

J-aggregates are an attractive supramolecular structure with interesting excitation properties found in the light-harvesting antenna of green sulfur bacteria. To structurally mimic the light-harvesting antenna, we synthesize J-aggregate nanotubes with a sharp and intense absorption band (J-band) by the coassembly of lithocholic acid (LCA) and 3,3'-dipropylthiadicarbocyanine iodide (DiSC3(5)) in aqueous solution. We show that the J-aggregate nanotubes can be used as a supramolecular probe for the sensitive and selective detection of dopamine (DA) in phosphate buffered saline (PBS) solution with the detection limit of ∼0.4 nM by simply observing the intensity change of the J-band due to the efficient photoinduced electron transfer from the J-aggregate nanotubes to the adsorbed DA.