Spectroscopic analysis and in vitro imaging applications of a pH responsive AIE sensor with a two-input inhibit function.

A novel terpyridine derivative formed stable aggregates in aqueous media (DMSO/H2O = 1/99) with dramatically enhanced fluorescence compared to its organic solution. Moreover, the ultra-violet absorption spectra also demonstrated specific responses to the incorporation of water. The yellow emission at 557 nm changed to a solution with intense greenish luminescence only in the presence of protons and it conformed to a molecular logic gate with a two-input INHIBIT function. This molecular-based material could permeate into live cells and remain undissociated in the cytoplasm. The new aggregation induced emission (AIE) pH type bio-probe permitted easy collection of yellow luminescence images on a fluorescent microscope. As designed, it displayed striking green emission in organelles at low internal pH. This feature enabled the self-assembled structure to have a whole new function for the pH detection within the field of cell imaging.