Two-in-one: a pH-sensitive, acridine-based, fluorescent probe binds G-quadruplexes in oncogene promoters

We report the synthesis of an acridine-containing cyanine dye and demonstrate its potential as a pH-responsive colorimetric indicator and fluorescent probe. Similarly to its parent molecule BRACO-19, this tri-substituted acridine also binds strongly to DNA quadruplexes found in the promoter region of oncogenes.