One-step synthesis of rhodamine-thiophene dyad and application for HOCl detection in vitro and vivo

Abstract

Hypochlorous acid (HOCl) plays important roles in many pathological and physiological processes. Herein we present a novel strategy to develop HOCl probe by one-step synthesis of rhodamine-thiophene dyad, rho-T. Unexpectedly, the thiophene moiety did not cause the fluorescence quenching of the xanthene moiety. Upon addition of HOCl, the ClO− anion attacks the carbon 9 position of rho-T and chlorinate the xanthene ring, resulting in fluorescence and absorption quenching of rho-T. rho-T exhibits linear response with increasing concentration of HOCl (R2 = 0.9875) with high sensitivity (Limit of Detection (LOD) = 2.36 nM) and selectivity in a fast response time (10 s). Finally, rho-T was successfully employed to detect HOCl in living cells and mice.