A new lysosome-targeted fluorescent probe for hydrogen peroxide based on a benzothiazole derivative.

As an important member of reactive oxygen species, hydrogen peroxide (HO) plays a key role in oxidative stress and cell signaling. Abnormal levels of HO in lysosomes can induce damage or even loss of lysosomal function, leading to certain diseases. Therefore, real-time monitoring of HO in lysosomes is very important. In this work, we designed and synthesized a novel lysosome-targeted fluorescent probe for HO-specific detection based on a benzothiazole derivative. A morpholine group was used as a lysosome-targeted unit and a boric acid ester was chosen as the reaction site. In the absence of HO, the probe exhibited very weak fluorescence. In the presence of HO, the probe showed an increased fluorescence emission. The fluorescence intensity of the probe for HO displayed a good linear relationship in the concentration range of HO from 8.0 × 10 to 2.0 × 10 mol·L. The detection limit was estimated to be 4.6 × 10 mol·L for HO. The probe possessed high selectivity, good sensitivity and short response time for the detection of HO. Moreover, the probe had almost no cytotoxicity and had been successfully applied to confocal imaging of HO in lysosomes of A549 cells. These results illustrated that the developed fluorescent probe in this study could provide a good tool for the determination of HO in lysosomes.