Paper Report for: Dai_2022_Luminescence__

Carboxylesterase (CEs), mainly localized in endoplasmic reticulum (ER), are responsible for hydrolyzing compounds containing various ester bonds. They have closely associated with drug metabolism and cellular homeostasis. Although some CE fluorescent probes have been developed, there are still a lack of probes that could target to ER. Here, we developed a novel fluorescent probe CR with specific ER anchor for monitoring CEs. In CR, p-toluenesulfonamide was chosen as precise ER targeting. Simple acetyl moiety was employed as CE response site and fluorescent modulation unit. During the spectral tests, CR displayed fast response speed (within 10s) towards CEs. Besides, it showed high sensitivity (LOD=5.1x10(-3) U/mL) and high selectivity with CEs. In biological imaging, probe CR could specially locate into ER in HepG2 cells. After cells treated with orilistat, CR has achieved in monitoring the changes of CEs. Importantly, CR also has ability of tracing the fluctuations of CEs in tunicamycin induced an ER stress model. Therefore, probe CR could be a powerful molecular tool for further investigating the functions of CEs in ER.