Yan-Ru Zhang

Novel pyrazoline-based fluorescent probe for detecting glutathione and its application in cells

A novel compound, 2-(1,5-diphenyl-4,5-dihydro-1H-pyrazol-3-yl)phenyl acrylate (probe L), was designed and synthesized as a highly sensitive and selective fluorescent probe for recognizing and detecting glutathione among cysteine, homocysteine and other amino acids. The structures of related compounds were characterized using IR, NMR and HRMS spectroscopy analysis. The probe is a non-fluorescent compound. On being mixed with glutathione in buffered EtOH:PBS=3:7 solution at pH 7.4, the probe exhibited the blue emission of the pyrazoline at 474 nm and a 83-fold enhancement in fluorescence intensity. This probe is very sensitive and displayed a linear fluorescence off-on response to glutathione with fluorometric detection limit of 8.2 × 10(-8)M. The emission of the probe is pH independent in the physiological pH range. Live-cell imaging of HeLa cells confirmed the cell permeability of the probe and its ability to selectively discriminate GSH from Cys and Hcy in cells. The toxicity of the probe was low in cultured HeLa cells.

A Ratiometric Fluorescent Probe Based on a Through‐Bond Energy Transfer (TBET) System for Imaging HOCl in Living Cells

A simple ratiometric probe (Naph-Rh) has been designed and synthesized based on a through-bond energy transfer (TBET) system for sensing HOCl. In this probe, rhodamine thiohydrazide and naphthalene formyl were connected by simple synthesis methods to construct a structure of monothio-bishydrazide. Free probe Naph-Rh showed only the emission of naphthalene. When probe Naph-Rh reacted with HOCl, monothio-bishydrazide could be converted into 1,2,4-oxadiazole, which not only ensured that the donor and the acceptor were connected with electronically conjugated bonds, but also resulted in the spiro-ring opening and the emission of rhodamine. Therefore, a typical TBET process took place. The probe possessed high-energy transfer efficiency and large pseudo-Stokes shifts. As the first TBET probe for HOCl, Naph-Rh showed excellent selectivity and sensitivity toward HOCl over other reactive oxygen species (ROS)/reactive nitrogen species (RNS), and could respond fast to a low concentration of HOCl in the real sample. In addition, the probe was suitable for imaging HOCl in living cells due to its real-time response, excellent resolution, and reduced cytotoxicity.

A novel pyrazoline-based selective fluorescent probe for detecting reduced glutathione and its application in living cells and serum

A new fluorescent probe, N-(4-(1,5-diphenyl-4,5-dihydro-1H-pyrazol-3-yl)phenyl)-2,4-dinitrobenzenesulfonamide (probe 3), was designed and synthesized as a highly sensitive and selective fluorescent probe for recognizing and detecting glutathione among biological thiols in aqueous media. Probe 3 is a nonfluorescent compound. On being mixed with biothiols under neutral aqueous conditions, the 2,4-dinitrobenzenesulfoyl moiety can be cleaved off by glutathione, and the blue emission of the pyrazoline at 464 nm is switched on, with a fluorescence enhancement of 488-fold for glutathione. Furthermore, probe 3 was highly selective for glutathione without interference from some biologically relevant analytes. The detection limit of glutathione was 4.11 × 10(-7) M. The emission of the probe is pH independent in the physiological pH range. Moreover, the probe can be used for fluorescent imaging of cellular glutathione and can be used for detecting glutathione in calf serum.

A ratiometric fluorescence sensor for HOCl based on a FRET platform and application in living cells

Studies showed that the intravascular pH of neutrophils fell to 4.5–5.0 with stimulation for a few minutes. Under this condition, myeloperoxidase was activated to catalyze H2O2 and Cl− to form hypochlorous acid (HOCl). Therefore, it is of significance to develop fluorescence probes for sensing HOCl in acid conditions. In this work, we reported a ratiometric probe CRSH based on a fluorescence resonance energy transfer (FRET) platform for detecting HOCl under acid conditions. Probe CRSH exhibited excellent sensitivity, high selectivity and a rapid response toward HOCl and is suitable for imaging endogenous HOCl in living cells.

Synthesis, X-ray crystal structure and optical properties of novel 1,3,5-triarylpyrazoline derivatives and the fluorescent sensor for Cu2+.

A series of novel 1,3,5-triarylpyrazoline derivatives was synthesized by the reaction of chalcone and 5-aryl-2-hydrazinyl-1,3,4-thiadiazole in 43.3-84.7% yields. The structures of compounds were characterized using IR, (1)H NMR and HRMS spectroscopy and X-ray diffraction analysis. The absorption and fluorescence characteristics of the compounds were investigated in dichloromethane, toluene, acetonitrile, N,N-dimethylformamide and tetrahydrofuran. The results showed that the absorption maxima of the compounds vary from 366 to 370nm depending on the group bound to benzene rings. The maximum emission spectra of the compounds in dichloromethane were dependent on nature of groups in benzene ring. Furthermore, the compound 3b can be used to determine Cu(2+) ion with high selectivity and a low detection limit in the DMF:H2O=1:1 (v/v) solution.

A simple yet effective fluorescent probe for detecting and imaging mercury ions in cells

We have synthesized rhodol hydrazide (RDH) as a simple fluorescent probe for detecting Hg2+. The probe can be applied in nontoxic solvents (EtOH and H2O). The probe has high selectivity and sensitivity to Hg2+ at pH 6–8. In addition, the probe has a superior capacity to resist interference from other ions. Both fluorescence intensity and absorbance have a linear relationship with the concentration of Hg2+, which ensured the precise detection of Hg2+. Furthermore, we have studied the intracellular Hg2+ imaging behavior of the probe on mammalian cells, which indicated that the probe can be applied to monitor Hg2+ within biological samples, especially in mammalian cells.

The effect of two novel amino acid-coated magnetic nanoparticles on survival in vascular endothelial cells, bone marrow stromal cells, and macrophages

Magnetic nanoparticles (MNPs) have been popularly used in many fields. Recently, many kinds of MNPs are modified as new absorbents, which have attracted considerable attention and are promising to be applied in waste water. In our previous study, we synthesized two novel MNPs surface-coated with glycine or lysine, which could efficiently remove many anionic and cationic dyes under severe conditions. It should be considered that MNP residues in water may exert some side effects on human health. In the present study, we evaluated the potential nanotoxicity of MNPs in human endothelial cells, macrophages, and rat bone marrow stromal cells. The results showed that the two kinds of nanoparticles were consistently absorbed into the cell cytoplasm. The concentration of MNPs@Gly that could distinctly decrease survival was 15 μg/ml in human umbilical vascular endothelial cells (HUVECs) or bone marrow stromal cells (BMSCs) and 10 μg/ml in macrophages. While the concentration of MNPs@Lys that obviously reduced viability was 15 μg/ml in HUVECs or macrophages and 50 μg/ml in BMSCs. Furthermore, cell nucleus staining and cell integrity assay indicated that the nanoparticles induced cell apoptosis, but not necrosis even at a high concentration. Altogether, these data suggest that the amino acid-coated magnetic nanoparticles exert relatively high cytotoxicity. By contrast, lysine-coated magnetic nanoparticles are more secure than glycine-coated magnetic nanoparticles.