Qingxia Duan

A highly specific and ultrasensitive fluorescent probe for basal lysosomal HOCl detection based on chlorination induced by chlorinium ions (Cl

The development of techniques for detecting HOCl at the subcellular level is very important to elucidate its cellular functions. Due to its relatively low concentration, it is still a great challenge to specifically track the basal HOCl in normal cells. In this paper, based on the unique chlorination of HOCl by the initiation of chlorinium ions (Cl+) in an acidic medium, we have developed a simple pH-mediated lysosome-targetable fluorescent probe Lyso-HOCl for the specific detection of HOCl over other bioactive molecules at higher concentration (500 μM). Our results show that Lyso-HOCl possesses a detection limit of 8.0 pM, and can quantitatively detect HOCl at the picomolar level. The ultrasensitive and ultrafast response property of probe Lyso-HOCl offers a good opportunity to monitor the basal HOCl and the fluctuation of endogenous HOCl levels in the lysosomes of macrophages (Raw 264.7 cells), and we thus anticipate that this probe would provide a promising tool for further unraveling the biological functions of HOCl in subcellular lysosomes.

A highly specific and ultrasensitive near-infrared fluorescent probe for imaging basal hypochlorite in the mitochondria of living cells

The development of highly specific and ultrasensitive fluorescent probes for tracking basal mitochondrial hypochlorite is very important to unravel its diverse cellular functions in the mitochondria of living cells. In this paper, we have developed a water-soluble, mitochondria-targeted near-infrared fluorescent probe NB-OCl for selectively measuring OCl- in the presence of higher concentration (500 μM) other biologically important substances. Surprisingly, the obtained results demonstrated that probe NB-OCl could sensitively determine OCl- in the range of 0-200 pM with the detection limit of 10.8 pM. To the best of our knowledge, NB-OCl is the first fluorescent probe for the specific determination of OCl- at the picomolar level. Moreover, probe NB-OCl exhibits a fast response for OCl- (< 5 s), which would be in favor of tracking the highly reactive and short-lived OCl- in the living systems. The preeminent recognition properties of probe NB-OCl enable its applications in the monitoring of basal OCl- and the fluctuations of endogenous/exogenous OCl- levels in the mitochondria of living cells.

A highly selective and ultrasensitive ratiometric fluorescent probe for peroxynitrite and its two-photon bioimaging applications

In this work, taking full advantage of the intramolecular charge transfer (ICT) mechanism, a hydroxynaphthalimide-based ratiometric two-photon fluorescent probe RTP-PN was synthesized to detect ONOO-. Probe RTP-PN could accurately detect ONOO- in the range of 1.4 nM-1.4 μM with the detection limit of 1.4 nM by a ratiometric fluorescence spectroscopy method. Additionally, probe RTP-PN exhibited an ultrafast response for ONOO- than other various species including H2O2 and ClO-. Finally, probe RTP-PN was successfully adopted to detect intracellular ONOO- by the two-photon excitation microscopy.