Construction of a lysosome-targetable ratiometric fluorescent probe for H2O2 tracing and imaging in living cells and an inflamed model

Hydrogen peroxide (H2O2), an important reactive oxygen species (ROS) with unique destructive oxidation properties, can be produced in lysosomes to fight off pathogens.

Taming ROS: Mitochondria-Targeted AIEgen for Neuron Protection via Photosensitization-Triggered Autophagy

<div> <p>Oxidative damages lead to accumulated harmful wastes, which in turn aggravate the related diseases and ROS imbalance. Therefore, provoking the defense system against severe oxidation and maintaining ROS homeostasis are desired. Herein, we used <a>a mitochondria</a>-targeted aggregation-induced emission luminogen (AIEgen) as a phototherapy agent for neuron protection by virtue of its efficient ROS generation in aggregates and mitochondrial delivery. It is demonstrated that controllable ROS generation within mitochondria can trigger defensive autophagy against oxidative damages in neuron cells. This work not only verifies the concept that taming ROS can be used for cell protection, but also provides a promising method to trigger autophagy against destructive oxidation, displaying broad prospects for alleviating oxidation-related diseases and promoting cell-based therapy.</p> </div>

Taming ROS: Mitochondria-Targeted AIEgen for Neuron Protection via Photosensitization-Triggered Autophagy

<div> <p>Oxidative damages lead to accumulated harmful wastes, which in turn aggravate the related diseases and ROS imbalance. Therefore, provoking the defense system against severe oxidation and maintaining ROS homeostasis are desired. Herein, we used <a>a mitochondria</a>-targeted aggregation-induced emission luminogen (AIEgen) as a phototherapy agent for neuron protection by virtue of its efficient ROS generation in aggregates and mitochondrial delivery. It is demonstrated that controllable ROS generation within mitochondria can trigger defensive autophagy against oxidative damages in neuron cells. This work not only verifies the concept that taming ROS can be used for cell protection, but also provides a promising method to trigger autophagy against destructive oxidation, displaying broad prospects for alleviating oxidation-related diseases and promoting cell-based therapy.</p> </div>

Redox-Reaction Products Of 4-Sulfo-2-(4'-Sulfonaphthalene-1'-Azo) Naphthol-1 With Ce(IV) - New Analytical Forms For Its Quantitative Determination

The results of redox interaction of Ce (IV) with 4-sulfo-2-(4’-sulfonaphthalene-1’-azo) naphthol-1 (carmosine- KAN) in aqueous solutions (pH 1.75) have been presented. The destructive oxidation of CAS into two fragments (2-nitroso-4-sulfonaphthol-1 (L1) and 1-nitroso-4-sulfonaphthalene (L2)) is accampanied by reduction of Ce(IV) to Ce(III). It was found that an increase in the Ce(III) -L1 -L2 system acidity to pH ~ 11 leads to formation of the [Ce(III)(ОН)2·L1·2Н2О] complex. After acetonitrile is introduced to [Ce(III)(ОН)2·L1 ·2Н2О] – L2 system (up to 40 % by volume) self-organization of products involving CH3CN is observed. The resulting water-acetonitrile system becomes turbid, and after ~10 min phase separation is observed. Phase I contains a solvate {L2·(CH3CN)п } of «straw» color (360 nm) and phase II (lower layer) contains solvated complex {[Ce (III) (ОН) 2 ·L 1 ·(CH 3 CN) 2 ]·(CH 3 CN)n} of «blue» color (640 nm). The use of these solvates allows determination of Ce(IV) in the range 2.2 ч 50.1 μg/cm3 (y = 0.5526с + 0.0575, R2 = 0.9917, ε360 = 6.2·103) and 4.2 ч 84.0 μg/cm3 (y = 0.1862c + 0.0265, R2 = 0.9952, ε640 = 2.05·103), respectively. The revealed dependence was used for indirect (volumetric) determination of Ce(IV) (y = -0.7857c + 20.4440, R2=0.9988). The methods was tested on standard samples of mineral origin and herbal pharmaceutical preparations.

Effect of Reaction Medium on V-Ti Oxide Catalyst Composition in 2-Methyl-5-Ethylpyridine Ammoxidation

<p>A chemical composition of V-Ti oxide catalyst changes in accordance with the reaction medium composition in a process of 2-methyl-5-ethylpyrydine ammoxidation into nicotinonitrile in an integral reactor. The presence of alkylpyridine concentration gradient along the catalyst bed leads to the appearance of V₂O₅ content gradient in the catalyst. V₂O₅ concentration increases in the conditions of alkylpyridine completed conversion in consequence of oxidative decomposition of VO₂-TiO₂ solid solution under the influence of N2O nitrogen oxide, which is formed upon the NH₃ oxidation. An increase of V₂O₅ contents over 5 wt% causes rising of the share of the 2-methyl-5-ethylpyridine and nicotinonitrile destructive oxidation. An introduction of small amounts of alkylpyridine directly into the catalyst bed permits to create the definite alkylpyridine concentration gradient, which the optimal content of V₂O₅ is corresponding to, for any given conditions of oxidative reaction. The catalysts containing 1-5 wt% of V₂O₅ and solid solution of VO₂-TiO₂ possess of the highest selectivity to nicotinonitrile.</p>