Rational Design of a Dual‐Site Fluorescent Probe for Selective Detection of Esterase/SO 2 and Its Bioimaging Application

In this work, a dual‐site fluorescent probe ES for selective detection of esterase and SO 2 was rationally designed. There are two molecules in probe ES , 1,8‐Naphthalimide and indole modified with iodoethane, and they were conjugated with double bond. The spectral data showed that probe ES could well respond to SO 2 and esterase separately or sequentially with dual emissions. For biological imaging, probe ES easily penetrated into cells, and it successfully detected exogenous and endogenous SO 2 in HepG2 and HeLa cells. Moreover, the probe was also applied for the detection of esterase change in these cells. Importantly, probe ES has succeeded in detecting esterase and SO 2 sequentially in these cells. Therefore, probe ES could possibly act as a value tool for exploring the physiological and pathological roles of esterase and SO 2 in living cells.