Fluorogenic Squaraine Dimers with Polarity-Sensitive Folding As Bright Far-Red Probes for Background-Free Bioimaging. - Karpenko, Iuliia A.; Collot, Mayeul; Richer, Ludovic; Valencia, Christel; Villa, Pascal; Mély, Yves; Hibert, Marcel; Bonnet, Dominique; Klymchenko, Andrey S. (Journal of the American Chemical Society, 2015)