A novel ratiometric fluorescent probe for specific detection of HSO3- at nanomolar level through 1, 4-Michael addition

Abstract

A Fluorescence Resonance Energy Transfer (FRET)-based ratiometric fluorescent probe, Cy-p-Np, was reported for specificial detection of HSO3− over anions and other Reactive Sulfur Species (RSS). In free probe, naphthalimide was selected as the donor while hemicyanine acted as the acceptor and the recognition unit for HSO3−. The probe Cy-p-Np displayed a ratiometric fluorescent response (I527/I590) to HSO3− with response time (150s) and limit detection (98.1 nM) based on the nucleophilic attack of HSO3− toward electrically positive hemicyanine. The proposed mechanism of nucleophilic HSO3−-promoted 1, 4-Michael addition reaction was proved by HRMS. The low toxicity allowed probe Cy-p-Np to be applied to detect exogenous HSO3− in living cells successfully. All the outstanding properties of probe Cy-p-Np provided the potential for the further application in live detection and even deeper biological applications.