Readily Accessible Fluorescent Probes for Sensitive Biological Imaging of Hydrogen Peroxide

Hydrogen peroxide is a major component of oxygen metabolism in biological systems that, when present in high concentrations, can lead to oxidative stress in cells. Noninvasive molecular imaging of H₂O₂ using fluorogenic systems represents an effective way to detect and measure the accumulation of this metabolite. Herein, we detail the development of robust H₂O₂‐sensitive fluorescent probes using a boronic ester trigger appended to the fluorophore through a benzyl ether linkage. A major advantage of the probes presented here is their synthetic accessibility, with only one step needed to generate the probes on the gram scale. The sensitivity of the probes was evaluated in simulated physiological conditions, showing micromolar sensitivity to H₂O₂. The probes were tested in biological model systems, demonstrating effective imaging of unstimulated, endogenous H₂O₂ levels in RAW 264.7 cells and murine brain tissue.     

Rational Design of a Ratiometric Fluorescent Probe Based on Arene–Metal‐Ion Contact for Endogenous Hydrogen Sulfide Detection in Living Cells

We report the design and development of a fluorescent Cd^II ion complex that is capable of the ratiometric detection of H₂S in living cells. This probe exploits the metal‐ion‐induced emission red shift resulting from direct contact between the aromatic ring of a fluorophore and a metal ion (i.e., arene–metal‐ion or “AM” contact). The Cd^II complex displays a large emission blue shift upon interaction with H₂S as the Cd^II‐free ligand is released by the formation of cadmium sulfide. Screening of potential ligands and fluorophores led to the discovery of a pyronine‐type probe, 6? Cd^II, that generated a sensitive and rapid ratio value change upon interaction with H₂S, without interference from the glutathione that is abundant in the cell. The membrane‐impermeable 6? Cd^II was successfully translocated into live cells by using an oligo‐arginine peptide and pyrenebutylate as carriers. As such, 6? Cd^II was successfully applied to the ratiometric detection of both exogenous and endogenous H₂S produced by the enzymes in living cells, thus demonstrating the utility of 6? Cd^II in biological fluorescence analysis.     

Glycosyl‐Modified Diporphyrins for in Vitro and in Vivo Fluorescence Imaging

The application of probes for optical imaging is becoming popular as they have high safety and good biocompatibility. We prepared two kinds of glycosyl‐modified diporphyrins, and their potentials as fluorescent probes were tested for the first time. After preparation of the glycosyl‐modified porphyrin monomers, Ag‐promoted coupling of the monomers was used to obtain glucose‐modified porphyrin dimer (GPD) and lactose‐modified porphyrin dimer (LPD). The strong interaction between the two porphyrin rings achieves red‐shifted emission, and thus circumvents autofluorescence and light‐scattering in biological samples. Although the glycosylation improves solubility, it also yielded selective attachment to cell membranes, and to chorions of early developmental‐stage zebrafish. Patch‐clamp experiments revealed the biocompatibility and low toxicity of GPD and LPD. Moreover, an in vivo imaging experiment provided direct evidence that zebrafish chorion contains sugar‐binding proteins. The modification and derivatization make porphyrins potential bioimaging probes for specific optical imaging.     

检测生物细胞H2S的一种选择性荧光恢复型探针

H2S是一项重要的生物信息传递者,但较少有生物相容的方法将之区分。本文报道了一种优良的荧光分子探针检测H2S,并区别于半胱氨酸,谷胱甘肽以及活性硫,氧,氮。设计的探针经证实能有效检测生物体内H2S。     

Tagging Live Cells that Express Specific Peptidase Activity with Solid‐State Fluorescence

A three‐component probe harnesses the extraordinary properties of a solid‐state fluorophore for the detection of living cells exhibiting a particular peptidase activity. The off–on mode by which the probe operates, the bright fluorescence of the resulting precipitate, and the rapid response allow an exceptional signal‐to‐background ratio during microscopic imaging. A tertiary carbamate link between the spacer and phenolic fluorophore is at the heart of the probe's long‐term stability. The degree of chlorination of the probe determines its response time and thus its suitability for live‐cell analysis. Our probe also allows highly resolved localization of peptidase activity during gel analysis or on agar. In comparison, probes releasing soluble fluorophores demonstrate complete diffusion of the fluorescent signal. These results demonstrate the probe's potential for diverse biomedical applications, including high‐fidelity flow cytometry and sensitive colony assays.     

焦炉煤气制氢生产高浓度双氧水

石焦集团利用自产焦炉煤气富含氢气的优势,通过变压吸附工艺制取高纯氢气,再用葸醌法技术生产加氢产品高浓度双氧水,为焦炉煤气深加工开辟了一条新路,延长了煤化工产业链,效益显著。     

Red Fluorescent Turn‐On Ligands for Imaging and Quantifying G Protein‐Coupled Receptors in Living Cells

Classical fluorescence‐based approaches to monitor ligand–protein interactions are generally hampered by the background signal of unbound ligand, which must be removed by tedious washing steps. To overcome this major limitation, we report here the first red fluorescent turn‐on probes for a G protein‐coupled receptor (oxytocin receptor) at the surface of living cells. The peptide ligand carbetocin was conjugated to one of the best solvatochromic (fluorogenic) dyes, Nile Red, which turns on emission when reaching the hydrophobic environment of the receptor. We showed that the incorporation of hydrophilic octa(ethylene glycol) linker between the pharmacophore and the dye minimized nonspecific interaction of the probe with serum proteins and lipid membranes, thus ensuring receptor‐specific turn‐on response. The new ligand was successfully applied for background‐free imaging and quantification of oxytocin receptors in living cells.     

A Fluorescent Probe for Imaging Sirtuin Activity in Living Cells,Based on One‐Step Cleavage of the Dabcyl Quencher

Sirtuins (SIRTs) are a family of NAD⁺‐dependent histone deacetylases. In mammals, dysfunction of SIRTs is associated with age‐related metabolic diseases and cancers, so SIRT modulators are considered attractive therapeutic targets. However, current screening methodologies are problematic, and no tools for imaging endogenous SIRT activity in living cells have been available until now. In this work we present a series of simple and highly sensitive new SIRT activity probes. Fluorescence of these probes is activated by SIRT‐mediated hydrolytic release of a 4‐(4‐dimethylaminophenylazo)benzoyl (Dabcyl)‐based FRET quencher moiety from the ?‐amino group of lysine in a nonapeptide derived from histone H3K9 and bearing a C‐terminal fluorophore. The probe SFP3 detected activities of SIRT1, ‐2, ‐3, and ‐6, which exhibit deacylase activities towards long‐chain fatty acyl groups. We then truncated the molecular structure of SFP3 in order to improve both its stability to peptidases and its membrane permeability, and developed probe KST‐F, which showed specificity for SIRT1 over SIRT2 and SIRT3. We show that KST‐F can visualize endogenous SIRT1 activity in living cells.     

过氧化氢氧化法合成四氯苯醌的研究

以对苯二酚,过氧化氢,盐酸为原料,以盐酸与醋酸(比例为2∶3)为溶剂,间歇滴加过氧化氢,阶梯程序升温反应,反应分别在45℃、70℃、95℃三阶段进行,原位生成氯气氯化合成四氯苯醌。合成四氯苯醌的收率和纯度都可达97%     

过氧化氢(H_2O_2)在现代经济发展中的应用

通过对过氧化氢(H2O2)的物理性质和化学性质的阐述,了解过氧化氢(H2O2)在纺织、化工行业、造纸、环保、电子、冶金、食品等行业的应用。     

高纯过氧化氢的生产及应用

简单介绍了高纯过氧化氢的规格和分析方法，详述了各种高纯过氧化氢制造技术，综述了国内外高纯过氧化氢的生产应用现状和发展趋势。     

Explosive Properties and Thermal Stability of Urea‐Hydrogen Peroxide Adduct

The adduct of urea and hydrogen peroxide (UHP) is industrially produced material on a large scale. Although UHP is widely used as a bleaching and oxidizing agent, its properties as energetic material are generally overlooked. In this work we report comprehensive characterization of UHP explosive and thermal properties. We found that UHP is a compound with a negative value of standard enthalpy of formation (−565.1 kJ mol⁻¹). It is not sensitive to impact and friction. However, we demonstrated that UHP (ρ =0.93 g cm⁻³; packed into a steel pipe with inner diameter of 206 mm) detonates with experimental velocity of detonation (VOD) of 3780 m s⁻¹. Moreover, for UHP with maximal theoretical density (ρ =1.43 g cm⁻³), the calculated VOD reaches 5219 m s⁻¹. Based on our findings, we recommend that present regulations regarding the handling, storage and transportation of the UHP should be revised, especially in cases, where UHP is kept on a large scale, under confinement and at places where the temperature can reach above 60 °C.     

Monitoring Biosensor Activity in Living Cells with Fluorescence Lifetime Imaging Microscopy

Live-cell microscopy is now routinely used to monitor the activities of the genetically encoded biosensor proteins that are designed to directly measure specific cell signaling events inside cells, tissues, or organisms. Most fluorescent biosensor proteins rely on Förster resonance energy transfer (FRET) to report conformational changes in the protein that occur in response to signaling events, and this is commonly measured with intensity-based ratiometric imaging methods. An alternative method for monitoring the activities of the FRET-based biosensor proteins is fluorescence lifetime imaging microscopy (FLIM). FLIM measurements are made in the time domain, and are not affected by factors that commonly limit intensity measurements. In this review, we describe the use of the digital frequency domain (FD) FLIM method for the analysis of FRET signals. We illustrate the methods necessary for the calibration of the FD FLIM system, and demonstrate the analysis of data obtained from cells expressing “FRET standard” fusion proteins. We then use the FLIM-FRET approach to monitor the changes in activities of two different biosensor proteins in specific regions of single living cells. Importantly, the factors required for the accurate determination and reproducibility of lifetime measurements are described in detail.     

过氧化氢及其精馏浓缩

根据过氧化氢精馏浓缩的特点,介绍一种节能和安全型的精馏流程及高新填料精馏塔。     

PDV分光光度法检测饮料中过氧化氢含量

建立可见分光光度法检测饮料中过氧化氢含量的方法;过氧化氢的含量在2.0~200.0 mg·L~(-1)范围内线性良好,相关系数在0.999以上,采用420 nm波长、0.5 m L PDV显色剂、显色时间10 min,平均回收率在97.24%~103.4%,检出限为2.0 mg·L~(-1);该方法精密度高、准确度好,适用于各种饮料中过氧化氢的定量分析。     

基于硫胺素荧光增强的可更新液滴荧光法用于痕量过氧化氢的测定

硫胺素在碱性条件下能被过氧化氢氧化成具有较强荧光的硫胺荧。基于此基本原理,利用连续动态液滴荧光法测定溶液中的痕量过氧化氢。连续产生与滴落的液滴可充当无光窗光池。在优化的实验条件下,传感器对2.5×10-5 mol/L～1.9×10-4 mol/L浓度范围内的过氧化氢具有良好的线性响应,检测限为4.88×10-6 mol/L。方法灵敏度高,选择性好,操作简单,试剂用量少。将其用于雨水中痕量过氧化氢的测定,结果满意。     

过氧化氢氧化法合成己二酸

分别以钨酸盐、过氧杂多化合物、杂多酸为催化剂 ,过氧化氢氧化法合成己二酸。详细介绍了该法的最新进展 ,认为过氧化氢工艺的开发和研究是己二酸清洁合成的方向     

离子选择电极法测定过氧化氢中的硝酸盐含量

开发了用离子选择电极法测定过氧化氢中硝酸盐含量的实验方法。从试样分解条件、pH值与回收率关系试验、定量方法等进行了探讨。精密度试验表明5次测定结果标准偏差为4.61%;回收率在96~100%。跟比色法结果对照,两者数据相近。本方法操作简便、快捷。     

非密闭条件下过氧化氢爆炸原因分析

为分析非密闭条件下高浓度过氧化氢的爆炸原因,设计了两种试验条件对爆炸发生的可能性进行模拟。第一种试验的条件是使高浓度过氧化氢处于完全敞开体系,第二种试验的条件是使高浓度过氧化氢与管件形成相对密闭区间。试验表明,爆炸只在第二种类型中发生。据此,建立了分析和解释爆炸发生原因的数值算法。