A triphenylamine-based colorimetric and fluorescent probe with donor­bridge­acceptor structure for detection of G-quadruplex DNA.

In this Letter, three triphenylamine-based dyes (TPA-1, TPA-2a and TPA-2b) with donor­bridge­acceptor (D­p­A) structure were designed and synthesized for the purpose of G-quadruplexes recognition. In aqueous conditions, the interactions of the dyes with G-quadruplexes were studied with the aim to establish the influence of the geometry of the dyes on their binding and probing properties. Results indicate that TPA-2b displays significant selective colorimetric and fluorescent changes upon binding of G-quadruplex DNA. More importantly, its distinct color change enables visual detection and differentiation of G-quadruplexes from single and duplex DNA structures. CD titration date reveals that TPA-2b could induce and stabilize the formation of G-quadruplex structure. All these remarkable properties of TPA-2b suggest that it should have promising application in the field of G-quadruplexes research.