Triazine pyridinium derivative supramolecular cascade assembly extended FRET for two-photon NIR targeted cell imaging.

A triazine pyridinium derivative (TAZpy) was encapsulated into the cavity of a cucurbit[7]uril and further assembled with sulfonatocalix[4]-arene, hyaluronic acid and commercial dyes, which not only achieved fluorescence cascade enhancement and an effective FRET process based on macrocyclic confinement, but was also applied in two-photon NIR targeted cell imaging.