Rational design of a fluorescent hydrogen peroxide probe based on the umbelliferone fluorophore

In this study, we report a novel water-soluble umbelliferone-based fluorescent probe for hydrogen peroxide. This probe shows very large increases (up to 100-fold) in fluorescent intensity upon reaction with hydrogen peroxide, and good selectivity over other reactive oxygen species (ROS).     

Development of a highly sensitive fluorescence probe for hydrogen peroxide

Hydrogen peroxide is believed to play a role in cellular signal transduction by reversible oxidation of proteins. Here, we report the design and synthesis of a novel fluorescence probe for hydrogen peroxide, utilizing a photoinduced electron transfer strategy based on benzil chemistry to control the fluorescence. The practical value of this highly sensitive and selective fluorescence probe, NBzF, was confirmed by its application to imaging of hydrogen peroxide generation in live RAW 264.7 macrophages. NBzF was also employed for live cell imaging of hydrogen peroxide generated as a signaling molecule in A431 human epidermoid carcinoma cells.     

Quantitative analysis of hydrogen peroxide by <Superscript>1</Superscript>H NMR spectroscopy

A technique utilizing ¹H NMR spectroscopy has been developed to measure the concentration of hydrogen peroxide from 10^–3 to 10 M. Hydrogen peroxide produces a peak at around 10–11 ppm, depending upon the interaction between solvent molecules and hydrogen peroxide molecules. The intensity of this peak can be monitored once every 30 s, enabling the measurement of changes in hydrogen peroxide concentration as a function of time. ¹H NMR has several advantages over other techniques: (1) applicability to a broad range of solvents, (2) ability to quantify hydrogen peroxide rapidly, and (3) ability to follow reactions forming and/or consuming hydrogen peroxide as a function of time. As an example, this analytical technique has been used to measure the concentration of hydrogen peroxide as a function of time in a study of hydrogen peroxide decomposition catalyzed by iron(III) tetrakispentafluorophenyl porphyrin.Electronic Supplementary Material Supplementary material is available for this article at     

硼酸及硼酸酯类过氧化氢荧光探针的最新研究进展

生物新陈代谢过程中产生的过氧化氢（H2O2）是生命活动所必需的,但是过量过氧化氢的存在可以引发多种疾病,因此对体内过氧化氢的检测具有重要意义.采用荧光探针法,借助激光共聚焦成像技术能够实现对活细胞和组织内的过氧化氢＂实时、可见、定量＂的检测,为深入阐明过氧化氢在生理和病理过程中所起的作用提供了一个重要手段.本文按荧光探针的结构分类,对近几年来以硼酸及硼酸酯基团作为荧光开关的具有高选择性和灵敏度的过氧化氢荧光探针进行了综述,主要探讨其设计思想、作用机制及应用,为过氧化氢探针的设计提供了新思路.     

Direct synthesis of hydrogen peroxide from hydrogen and oxygen over Pd-supported HNb<Subscript>3</Subscript>O<Subscript>8</Subscript> metal oxide nanosheet catalyst

A two-dimensional layered niobium oxide and its exfoliated nanosheet were examined as potential solid acid supports for direct synthesis of hydrogen peroxide from hydrogen and oxygen under intrinsically safe and noncorrosive reaction conditions. The catalytic performance strongly depended on the acid strength of the support material. The Pd-supported protonated niobium oxide nanosheet catalyst (Pd/HNb₃O₈-NS) with remarkably enhanced acidity was superior to layered Pd/KNb₃O₈ or Pd/HNb₃O₈ to promote the reaction. Hydrogen peroxide decomposition testing revealed that, although HNb₃O₈ was comparable to its exfoliated counterpart, HNb₃O₈-NS, in suppressing hydrogen peroxide decomposition without hydrogen, HNb₃O₈ was virtually ineffective in preventing hydrogen peroxide hydrogenation in the presence of hydrogen. However, compared with HNb₃O₈, HNb₃O₈-NS was found to be still effective at suppressing hydrogen peroxide hydrogenation. The different efficiency observed between HNb₃O₈ and HNb₃O₈-NS in the prevention of hydrogen peroxide hydrogenation implies that use of a highly acidic support is advantageous to effectively suppress faster and therefore more unfavorable hydrogen peroxide hydrogenation compared with decomposition. This result clearly demonstrates that the highly acidic HNb₃O₈ nanosheet can serve as an efficient solid acid support for direct synthesis of hydrogen peroxide from hydrogen and oxygen.     

Hydrogen Peroxide‐mediated Inactivation of Two Chloroplastic Peroxidases,Ascorbate Peroxidase and 2‐Cys Peroxiredoxin†

Reactive oxygen species (ROS), such as the superoxide anion and hydrogen peroxide, are generated by the photosystems because photoexcited electrons are often generated in excess of requirements for CO₂ fixation and used for reducing molecular oxygen, even under normal environmental conditions. Moreover, ROS generation is increased in chloroplasts if plants are subjected to stresses, such as drought, high salinity and chilling. Chloroplast‐localized isoforms of ascorbate peroxidase and possibly peroxiredoxins assume the principal role of scavenging hydrogen peroxide. However, in vitro studies revealed that both types of peroxidases are easily damaged by hydrogen peroxide and lose their catalytic activities. This is one contributing factor for cellular damage that occurs under severe oxidative stress. In this review, I describe mechanisms of hydrogen peroxide‐mediated inactivation of these two enzymes and discuss a reason why they became susceptible to damage by hydrogen peroxide.     

A targetable fluorescent probe for imaging hydrogen peroxide in the mitochondria of living cells

We present the design, synthesis, and biological applications of mitochondria peroxy yellow 1 (MitoPY1), a new type of bifunctional fluorescent probe for imaging hydrogen peroxide levels within the mitochondria of living cells. MitoPY1 combines a chemoselective boronate-based switch and a mitochondrial-targeting phosphonium moiety for detection of hydrogen peroxide localized to cellular mitochondria. Confocal microscopy and flow cytometry experiments in a variety of mammalian cell types show that MitoPY1 can visualize localized changes in mitochondrial hydrogen peroxide concentrations generated by situations of oxidative stress.     

An ICT-based approach to ratiometric fluorescence imaging of hydrogen peroxide produced in living cells

We present the synthesis, properties, and biological applications of Peroxy Lucifer 1 (PL1), a new fluorescent probe for imaging hydrogen peroxide produced in living cells by a ratiometric response. PL1 utilizes a chemoselective boronate-based switch to detect hydrogen peroxide by modulation of internal charge transfer (ICT) within a 1,8-naphthalimide dye. PL1 features high selectivity for hydrogen peroxide over similar reactive oxygen species, including superoxide, and nitric oxide, and a 65 nm shift in emission from blue-colored fluorescence to green-colored fluorescence upon reaction with peroxide. Two-photon confocal microscopy experiments in live macrophages show that PL1 can ratiometrically visualize localized hydrogen peroxide bursts generated in living cells at immune response levels.     

On the stability of Al<Subscript>13</Subscript> Keggin cation in aqueous hydrogen peroxide solutions

We report the first attempt to study the behavior of the [AlO₄Al1₂(OH)₂₅(H₂O)₁₁]⁶⁺ (Al₁₃) Keggin cation (KC) in water–peroxide solutions. Addition of hydrogen peroxide into an aqueous solution containing the Al₁₃ KC reduces pH due to the acidity of hydrogen peroxide. According to the ²⁷Al NMR studies of water–peroxide solutions prepared just before the NMR experiment, with their pH adjusted to the initial value of 5.5 with aqueous NaOH, the Al₁₃ KC concentration decreases immediately once hydrogen peroxide is added to the initial system. Addition of 18.2 wt % hydrogen peroxide to the initial 0.88 mM Al₁₃ solution gives rise to a fourfold decline in Al₁₃ polyoxo cation concentration to 0.22 mM. Then, the KC concentration in the test system remains unchanged for 1 week. Large hydrogen peroxide amounts (27.9 wt % or higher) added to the initial system almost completely degrade the KC. Sodium sulfate added to the initial water–peroxide solution of Al₁₃ chloride where the hydrogen peroxide concentration is 5.5 wt % precipitates the earlier described Al₁₃ sulfate [AlO₄Al₁₂(OH)₂₅(H₂O)₁₁](SO₄)₃ · 16H₂O, where the aluminum polyoxo cation does not contain coordinated hydrogen peroxide molecules, peroxo or hydroperoxo groups as shown by X-ray diffraction.     

Amperometric aspartate electrode

An amperometric enzyme electrode for L-aspartate determination was developed. The probe consisted of a platinum electrode which senses hydrogen peroxide produced from the reactions catalyzed by two enzymes co-immobilized on a preactivated polymeric membrane, α-Ketoglutarate in the presence of L-aspartate was transaminated to L-glutamate by aspartate aminotransferase and the glutamate produced was oxidized by glutamate oxidase, with concomitant production of hydrogen peroxide. Additional protective membranes eliminated interferences from glutamate and most electroactive compounds. The response curve of the probe was linear over the concentration range 1.0 × 10^?6 M to 2.0 × 10^?4 M aspartate and was useful for at least two months. Aspartic acid in some pharmaceutical products was determined and the results correlated well with a liquid chromatographic reference method and the manufacturer's specification.     

Automatic enzymatic determination of glucose with a potentiometric sulphur dioxide probe

An automatic, continuous-flow system for the determination of glucose is reported, with a sulphur dioxide probe used as the sensor for an indicator reaction with hydrogensulphite. In the presence of glucose oxidase, glucose is selectively oxidised to produce hydrogen peroxide at a rate proportional to the glucose concentration. The oxidation of hydrogensulphite by the hydrogen peroxide is rapidly monitored by the probe at sampling rates as high as 90 samples per hour. Proteins and reducing substances, such as cysteine, uric acid and ascorbic acid interfere only in large amounts. The method is applicable to biological fluids without prior separation steps.     

Amperometric determination of sulfite with sulfite oxidase immobilized at a platinum electrode surface

Sulfite oxidase is immobilized on collagen membrane at the surface of a platinum electrode and catalyzes the oxidation of sulfite to sulfate with stoichiometric production of hydrogen peroxide. The hydrogen peroxide is detected amperometically at the platinum electrode at an applied potential of 700 mV. The system responds linearly to sulfite in the range 1–150 μM, with a detection limit of 0.2 μM. The enzyme retains over 95% of its activity for three weeks if stored at ?20° C when the probe is not in use.     

A charge transfer assisted fluorescent probe for selective detection of hydrogen peroxide among different reactive oxygen species

A charge transfer assisted fluorescent probe is synthesized which undergoes a change in fluorescence emission at two different wavelengths in the presence of hydrogen peroxide.     

The monooxidation of ethylene with hydrogen peroxide on the per-FTPhPFe<Superscript>3+</Superscript>OH/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> biomimetic

The gas-phase monooxidation of ethylene by hydrogen peroxide on a biomimetic heterogeneous catalyst (per-FTPhPFe³⁺OH/Al₂O₃) was studied under comparatively mild conditions. The biomimetic oxidation of ethylene with hydrogen peroxide was shown to be coherently synchronized with the decomposition of H₂O₂. Depending on reaction medium conditions, one of two desired products was formed, either ethanol or acetaldehyde. The kinetics and probable mechanism of ethylene transformation were studied.     

Substitutions homolytiques intramoléculaires. 17. Décomposition de peroxydes de ϵ-alcényle et de t-butyle. Accès à des tétrahydropyranes substitués

The induced decomposition of t-butyl hex-5-enyl peroxide in good hydrogen donor solvents led to 2-substitude tetrahydropyrans and adduct peroxides. The presence of substituents on the hexenyl moinety influenced seriously the relative ratio of the heterocycle and the adduct peroxide.     

A novel biosensor for specific determination of hydrogen peroxide: catalase enzyme electrode based on dissolved oxygen probe

A biosensor for the specific determination of hydrogen peroxide was developed using catalase (EC 1.11.1.6) in combination with a dissolved oxygen probe. Catalase was immobilized with gelatin by means of glutaraldehyde and fixed on a pretreated teflon membrane served as enzyme electrode. The electrode response was maximum when 50 mM phosphate buffer was used at pH 7.0 and at 35 degrees C. The biosensor response depends linearly on hydrogen peroxide concentration between 1.0x10(-5) and 3.0x10(-3) M with a response time of 30 s. The sensor is stable for >3 months so in this period >400 assays can be performed.     

Synthesis of reversible carbon dioxide absorber based on hydrated zirconium oxide,intended for concentration and removal of CO<Subscript>2</Subscript> in habitable closed objects

Carbon dioxide absorber based on hydrated zirconium oxide was synthesized with ammonium carbonate and hydrogen peroxide. The effect of the molar ratio between ammonium carbonate and hydrogen peroxide on the sorption characteristics of the absorber was examined. The structural-sorption properties of the absorber were analyzed. It was shown tat the absorber has a high absorption capacity for CO₂.     

Simultaneous Determination of Glucose and L‐Glutamate Using a Capillary Enzyme Reactor with Electrochemical Detection

An electrophoresis capillary that incorporates two enzymes for the simultaneous determination of glucose and L ‐glutamate is described. The enzymes deposited along the separation capillary walls react with their respective substrate as they are separated during the electrophoresis to produce hydrogen peroxide that is detected by amperometry as the hydrogen peroxide zone emerges from the end of the capillary. Even though both enzyme reactions produce a common product, hydrogen peroxide, the hydrogen peroxide produced by each enzyme reaction stays in narrow zones that migrate the length of the capillary at different rates. The rate of migration for the individual H₂O₂ zones is consistent with the expected mobility of neutral glucose and of anionic L ‐glutamate, respectively. This property allows each enzyme substrate to be characterized in a single experiment and in the presence of other electroactive substances.     

Effect of solvent nature on the catalytic activity of iron-containing pyrocatecholsulfonic cationite in the reactions of H<Subscript>2</Subscript>O<Subscript>2</Subscript> decomposition and benzene hydroxylation

Kinetics of hydrogen peroxide decomposition under the conditions of heterogenous catalysis with iron-containing pyrocatecholsulfonic cationite at 50°C in dimethyl sulfoxide, tetrahydrofuran, dioxane, acetonitrile, and nitromethane was studied. The value of rate constant of hydrogen peroxide decomposition in these solvents was found to diminish with increase of solvent nucleophilicity. At the hydroxylation of benzene in the aqueous acetonitrile medium the formation of phenol was observed. The phenol yield was found to depend on the composition of the binary solvent acetonitrile-water.     

SnFe2O4 Nanocrystals as Highly Efficient Catalysts for Hydrogen‐Peroxide Sensing

SnFe₂O₄ nanocrystals (NC), prepared with a simple one‐step carrier‐solvent‐assisted interfacial reaction process, were developed as highly efficient catalysts for hydrogen peroxide sensing. These NCs, with a size of around 7 nm, served as the sensing catalyst and were decorated onto the pore surfaces of a porous fluorine‐doped tin oxide (PFTO) host electrode, prepared from commercial FTO glass with a simple anodic treatment, to form the sensing electrode for hydrogen peroxide. The SnFe₂O₄ NCs‐loaded PFTO electrode exhibited an ultra‐high sensitivity of 1027 mA m ^?1 cm^?2 toward hydrogen peroxide, outperforming Pt NCs‐loaded PFTO electrodes. The SnFe₂O₄ NCs‐loaded PFTO electrode proved a promising relatively low cost, high performance sensing electrode for hydrogen peroxide.