[Markers of chloric acid (I) in biological systems--identification and properties]. / Markery kwasu chlorowego (I) w ukladach biologicznych--identyfikacja i wlasciwosci.

Reactive oxygen and nitrogen species are attributed to initiation and propagation of many diseases. The demonstration of elevated activity of myeloperoxidase and the level of 3-chlorotyrosine in atherosclerosis, kidney diseases and chronic inflammations brought about the interest in the biological role of another strong oxidant--hypochlorite. Concentration of this compound is extremely difficult to estimate in vivo and in vitro because of its high reactivity. The reaction of hypochlorite with biological compounds lead to formation of chlorohydrins, glutathione sulfonamides, chloramines, 3- and 3,5-dichlorotyrosines and chlorinated DNA bases (8-chloroadenine, 8-chloroguanine, 5-chlorocytosine and 5-chlorouracil). At least some of these products of hypochlorite action are believed to provide specific HOCl-biomarkers, useful especially in the analysis of clinical samples, using sensitive detection techniques.

Selective visualization of endogenous hypochlorous acid in zebrafish during lipopolysaccharide-induced acute liver injury using a polymer micelles-based ratiometric fluorescent probe.

The development of effective method for monitoring of endogenous hypochlorous acid (HClO) in vivo is of great significance for early diagnosis of lipopolysaccharide (LPS) induced acute liver injury. Herein, we report a polymer micelles-based ratiometric fluorescent probe (PM) based on the combination of intramolecular charge transfer (ICT) mechanism and fluorescence resonance energy transfer (FRET) principle for selective visualization of endogenous HClO in vivo. Upon the reaction of PM with HClO, the electron-donating thiourea moiety is oxidized and transformed into imidazoline moiety (electron-withdrawing group), resulting in a dramatic blue shift (˃100nm) in the fluorescence emission. The as-prepared PM shows good water dispersibility (100% aqueous media), fast response (<40s), high sensitivity (a detection limit of 1.75nM), and outstanding selectivity toward HClO over other ROS/RNS (50 equiv.). In addition, the vivo imaging experiments demonstrate that PM facilitates the visualization of endogenous HClO generation with LPS induced acute liver injury in zebrafish model.

Pyrene Derivative Emitting Red or near-Infrared Light with Monomer/Excimer Conversion and Its Application to Ratiometric Detection of Hypochlorite.

Fluorescent sensors are attractive and versatile tools for both chemical sensing and biological imaging. Herein, a novel pyrene derivative fluorophore, Py-Cy, possessing the monomer/excimer conversion feature, was synthesized; and the design rationale for this fluorophore is combination of extending conjugation length and incorporating donor-π-acceptor structure. The positively charged Py-Cy shows quite good water solubility and exhibits absorption in the visible-light range, and its monomer and excimer emit red light and near-infrared light respectively, which is extremely beneficial for biosensing or bioimaging. To explore the potential utilization of this new fluorophore, we choose hypochlorite as a model analyte, which can break the double bond in the molecular structure, thereby generating the water-insoluble pyrenecarboxaldehyde; this process correspondingly leads to fluorescence changes and thus affords the ratiometric fluorescent detection of hypochlorite in real samples and cell imaging. The approach offers new insights for designing other fluorophores which emit red or near-infrared light and for devising technically simple ratiometric fluorescent sensors.

[Identification of key toxicants in a bleaching effluent--a case study].

The toxicity identification evaluation (TIE) was conducted with a toxic bleaching effluent to identify its toxic components. Toxicity characterisation procedures (phase I) indicated that the primary toxicants in the effluent were volatile, and could be reduced by sodium thiosulfate. Toxicity-based fractionation techniques (phase II) were conducted, and the oxidation organic chloridates were found not to be the major toxicants. Deletion approach of phase III confirmed that the toxicity decreased with the decrease of free and total residual chlorine concentrations, indicating that Cl2, HClO and ClO- were identified as primary toxicants in the effluent.