Xiaojie Jiao

A highly selective and sensitive fluorescent probe for hypochlorous acid and its lysosome-targetable biological applications

A novel lysosome-targetable fluorescence probe PT-1 based on a photoinduced electron transfer (PET) mechanism has been designed and synthesized. For comparison, the probe PT-2 without morpholine moiety as a lysosome-directing group was also synthesized and investigated. Probes PT-1 and PT-2 exhibited high selectivity, high sensitivity (with the detection limits down to the 10-10M range) and response in real time (within 10s) toward HOCl over other reactive oxygen species (ROS). Both PT-1 and PT-2 were cell permeable and enabled them to be used for monitoring of HOCl in living cells. Meanwhile, the probe PT-1 demonstrated an accurately lysosome-targeting ability, and was successfully applied to image of exogenous, endogenous produced HOCl in living cells. The success of subcellular imaging suggested that the probe PT-1 could be used in further applications for the investigation of biological functions and pathological roles of HOCl at organelle levels.

A rhodamine-based fast and selective fluorescent probe for monitoring exogenous and endogenous nitric oxide in live cells

Nitric oxide, an important cellular messenger molecule, plays a wide range of physiological roles in neurotransmission, vascular relaxation, platelet activation, and immune response. In this work, we synthesized a selective and sensitive cationic fluorescent probe (ROPD) for monitoring exogenous and endogenous nitric oxide in live cells by grafting a NO-trapper o-phenylenediamine (OPD), via one of the amino groups of OPD, onto a rhodamine fluorophore at the C-3 position. The probe exhibited high selectivity and sensitivity towards NO with fast response in the water phase over a wide pH range. At the same time, the probe ROPD is cell-membrane permeable and can be used for the real-time visualization of exogenous NO in both L929 and HeLa cells, and endogenous NO in stressed RAW 264.7 cells.

Synthesis and bioapplication of a highly selective and sensitive fluorescent probe for HOCl based on a phenothiazine–dicyanoisophorone conjugate with large Stokes shift

Herein, a fluorescent probe, Dcp-EPtz, for HOCl based on a strong push–pull phenothiazine–dicyanoisophorone conjugate was prepared. The probe exhibits a very large Stokes shift of over 170 nm. Dcp-EPtz turns out to be a fast-responsive (<10 s) fluorescent probe for HOCl with high selectivity and sensitivity. It shows a good linear relationship between the enhanced fluorescence intensity at 617 nm and the concentration of hypochlorous acid in the range 0–10 μM, with the detection limit of 3.9 × 10−8 M. Moreover, the probe Dcp-EPtz exhibits the ability for endogenous HOCl monitoring in living cells.