scholarly journals Construction of a Turn Off-On-Off Fluorescent System Based on Competitive Coordination of Cu2+between 6,7-Dihydroxycoumarin and Pyrophosphate Ion for Sensitive Assay of Pyrophosphatase Activity

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Lingzhi Zhao ◽  
Liu Zhao ◽  
Yanqing Miao ◽  
Chunye Liu ◽  
Chenxiao Zhang
Keyword(s):  
Fluorescent Probe ◽  
Reaction System ◽  
Water Soluble ◽  
Sensitive Assay ◽  
Optimum Conditions ◽  
Activity Assay ◽  
Competitive Coordination ◽  
Hydrolysis Of ◽  
Subsequent Addition

The detection of pyrophosphatase (PPase) activity is of great significance in diagnosing diseases and understanding the function of PPase-related biological events. This study constructed a turn off-on-off fluorescent system for PPase activity assay based on PPase-regulated competitive coordination of Cu2+between a water-soluble fluorescent probe 6,7-dihydroxycoumarin (DHC) and pyrophosphate (PPi). The probe DHC can coordinate with Cu2+and consequently display on-off type fluorescence response. Furthermore, the in situ formed nonfluorescent Cu2+-DHC complex can act as an effective off-on type fluorescent probe for sensing PPi due to the higher coordination reactivity between Cu2+and PPi than that between Cu2+and DHC. The subsequent addition of PPase to the mixture containing Cu2+, DHC, and PPi leads to the fluorescence requenching of the system again (an off state) because PPase catalyzes the hydrolysis of PPi into orthophosphate in the reaction system. Under the optimum conditions, the decrease of the fluorescence intensity of DHC-Cu2+-PPi system was linear with the increase of the PPase activity in the range from 0.1 to 0.3 U. The detection limit was down to 0.028 U PPase (S/N=3). Moreover, the as-established system was also applied to evaluate PPase inhibitor. This study offers a simple yet effective method for the detection of PPase activity.

scholarly journals Quantum Dot Doping-Induced Photoluminescence for Facile, Label-Free, and Sensitive Pyrophosphatase Activity Assay and Inhibitor Screening

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 111 ◽  
Author(s):  
Yishen Tian ◽  
Lijie Hao ◽  
Chao Wang ◽  
Xiaoyan Yang ◽  
Shufeng Liu
Keyword(s):  
Quantum Dot ◽  
Disease Diagnosis ◽  
Label Free ◽  
Sensitive Assay ◽  
Activity Assay ◽  
Inhibitor Screening ◽  
Assay Methods ◽  
Pyrophosphatase Activity ◽  
Hydrolysis Of ◽  
Promising Avenue

Development of simple, convenient, and sensitive assay methods for pyrophosphatase (PPase) activity is of importance, for disease diagnosis and drug discovery. Herein, a simple, rapid, label-free, and sensitive fluorescence sensor for PPase activity assay is developed, using Cu2+ doping-induced quantum dot (QD) photoluminescence as a signal reporter. The Cu2+ doping of ZnSe QD can induce a dopant-dependent emission response, which will be inhibited after the premixing of Cu2+ with pyrophosphate (PPi), to form a Cu2+-PPi complex. Then, the hydrolysis of PPi into phosphate (Pi), specifically catalyzed by PPase, liberates the free Cu2+ to regain the QD doping for the fluorescence response, which is highly dependent on the PPase activity. The PPase can be sensitively and selectively assayed, with a detection limit of 0.1 mU/mL. The developed sensing strategy can be also employed for the PPase inhibitor screening. Thus, the current QD doping-based sensing strategy offers an efficient and promising avenue for Cu2+, PPi, or PPase-related target analysis, and might hold great potential for the further applications in the clinical disease diagnosis.

scholarly journals Selective and Sensitive Detection of Cyanide Based on the Displacement Strategy Using a Water-Soluble Fluorescent Probe

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Ming La ◽  
Yuanqiang Hao ◽  
Zhaoyang Wang ◽  
Guo-Cheng Han ◽  
Lingbo Qu
Keyword(s):  
Aqueous Solution ◽  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Water Soluble ◽  
World Health ◽  
Selective Detection ◽  
Highly Sensitive ◽  
Health Organization

A water-soluble fluorescent probe (C-GGH) was used for the highly sensitive and selective detection of cyanide (CN−) in aqueous media based on the displacement strategy. Due to the presence of the recognition unit GGH (Gly-Gly-His), the probeC-GGH can coordinate with Cu2+and consequently display ON-OFF type fluorescence response. Furthermore, thein situformed nonfluorescentC-GGH-Cu2+complex can act as an effective OFF-ON type fluorescent probe for sensing CN−anion. Due to the strong binding affinity of CN−to Cu2+, CN−can extract Cu2+fromC-GGH-Cu2+complex, leading to the release ofC-GGH and the recovery of fluorescent emission of the system. The probeC-GGH-Cu2+allowed detection of CN−in aqueous solution with a LOD (limit of detection) of 0.017 μmol/L which is much lower than the maximum contaminant level (1.9 μmol/L) for CN−in drinking water set by the WHO (World Health Organization). The probe also displayed excellent specificity for CN−towards other anions, including F−, Cl−, Br−, I−, SCN−,PO43-,N3-,NO3-, AcO−,SO42-, andCO32-.

In situ construction of a self-assembled AIE probe for tumor hypoxia imaging

Nanoscale ◽  
2020 ◽  
Vol 12 (14) ◽  
pp. 7509-7513 ◽  
Author(s):  
Tianhao Xue ◽  
Kuanchun Shao ◽  
Jingyuan Xiang ◽  
Xinyi Pan ◽  
Zixuan Zhu ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Self Assembly ◽  
Tumor Hypoxia ◽  
Water Soluble ◽  
Hypoxia Imaging ◽  
Self Assembled

A novel hypoxia-responsive fluorescent probe of a hydrophilic azobenzene containing copolymer combined with a carbamate linkage and anionic water-soluble tetraphenylethene by using the in situ self-assembly concept for tumor hypoxia imaging is reported.

A hepatocyte-targeting fluorescent probe for imaging isoniazid-induced hydrazine in HepG2 cells and zebrafish

2020 ◽  
Vol 56 (91) ◽  
pp. 14183-14186
Author(s):  
Zhenbo Guo ◽  
Mei Wang ◽  
Xueyan Li ◽  
Xu Jia ◽  
Xiaoli Wang ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Hepg2 Cells ◽  
Hydrolysis Of

A novel hepatocyte-targeting fluorescent N2H4 probe was first prepared. The probe can be used to image N2H4 produced by the hydrolysis of isoniazid in HepG2 cells and the liver of zebrafish in situ.

Transmembrane gradients of free Na+ in isolated heart mitochondria estimated using a fluorescent probe

1992 ◽  
Vol 262 (4) ◽  
pp. C1047-C1055 ◽  
Author(s):  
D. W. Jung ◽  
L. M. Apel ◽  
G. P. Brierley
Keyword(s):  
Fluorescent Probe ◽  
Free Acid ◽  
Isolated Heart ◽  
Heart Mitochondria ◽  
Excitation Spectra ◽  
Acetoxymethyl Ester ◽  
The Matrix ◽  
Isolated Pig Heart ◽  
Hydrolysis Of

The concentration of free Na+ in the matrix of isolated pig heart mitochondria has been monitored using the fluorescent probe sodium-binding benzofuran isophthalate (SBFI) developed by Minta and Tsien (J. Biol. Chem. 264: 19449-19457, 1989). SBFI was sequestered in the matrix by hydrolysis of the permeant acetoxymethyl ester. The sequestered probe showed altered quantum efficiency and excitation spectra in the presence and absence of Na+ when compared with SBFI free acid in solution. Fluorescence was calibrated in situ by using ionophores to equilibrate matrix [Na+] with external [Na+]. SBFI fluorescence showed that matrix [Na+] increased linearly as external [Na+] was increased to 95 mM in the presence or absence of respiration. Respiring mitochondria maintained a Na+ gradient (Na+ out greater than Na+in) of approximately 8.0. The corresponding gradient in nonrespiring mitochondria was approximately 2.0. The Na+ gradient was nearly equivalent to the H+ gradient in the presence or absence of respiration. The uptake of Pi by respiring mitochondria decreased matrix pH and increased matrix [Na+]. It is concluded that isolated mitochondria maintain a Na+ gradient across the inner membrane as a result of the activity of the endogenous Na(+)-H+ antiport.

scholarly journals Expanding structural diversity in a library of disulfide macrocycles through in-situ imide hydrolysis

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Marcin Konopka ◽  
Artur R. Stefankiewicz
Keyword(s):  
Phase Transfer ◽  
Structural Diversity ◽  
Single Step ◽  
Water Soluble ◽  
One Pot ◽  
Dynamic Covalent Chemistry ◽  
Complex Process ◽  
Dmso Concentration ◽  
Hydrolysis Of

AbstractWe describe here an unorthodox approach to dynamic covalent chemistry in which the initially-unexpected in-situ hydrolysis of a bis-imide is employed to control the composition of a library of structurally diverse macrocycles. A single building block is used to generate a library of numerous disulfide-based architectures in a one-pot single-step process. The dual-stimuli method is based on simultaneous changes in pH and DMSO concentration to expand the structural diversity of the macrocyclic products. Mechanistic details of this complex process are investigated by the kinetics analysis. We delivered a facile strategy for the synthesis of water-soluble, multicomponent and dynamic macrocycles equipped with number of different functional groups, thus giving a prospect of their application in guest-driven phase transfer.

Novel environmentally friendly tannin-cyclohexanone formaldehyde resin for high performance applications

2019 ◽  
Vol 49 (2) ◽  
pp. 96-101
Author(s):  
Nilgun Kızılcan ◽  
Selda Sert
Keyword(s):  
Organic Solvents ◽  
Condensed Tannin ◽  
Reaction System ◽  
Environmentally Friendly ◽  
Water Soluble ◽  
Formaldehyde Resin ◽  
Step Method ◽  
Content Type ◽  
Naoh Solution

Purpose Cyclohexanone-formaldehyde resin (CFR) was in situ modified with tannin (T) in the presence of sodium hydroxide. The purpose of this study is to produce eco-friendly tannin-modified cyclohexanone resins (TCFR) with a one-step method that has higher decomposition temperature than CFR. The solubility, molecular weight and thermal properties of the product were investigated. Design/methodology/approach Cyclohexanone, formalin (37 per cent aqueous solution) and tannin were mixed and 20 per cent aqueous NaOH solution was added to produce the resin. Tannin has environmentally friendly bio-based phenolic compounds that the tannin structure has been incorporated into the structure of the cyclohexanone formaldehyde resin during the in situ modification of resin, such as resole resin. Findings The improvement of the properties of the TCFRs produced from condensed tannin. TCFRs were soluble in common organic solvents. The product TCFR has a dark red colour. Research limitations/implications The reaction mixture must be stirred continuously. Subsequently, 37 per cent formalin was added drop-wise in total while refluxing. The amount of aqueous NaOH solution of it is limited, as the formed resin may become insoluble in common organic solvents. At the end of the reaction, a water-soluble resin is obtained. Then, the water of water phase was removed from TCFR reaction system, successively by evaporating with rotary evaporator. Practical implications This study provides the application of ketonic resins. The TCFR containing tannin groups may also promote the adhesive strength of a coating. Social implications These resins may be used for the preparation of adhesive. Condensed tannin, with a large amount of Catechol groups was considered for reducing the formaldehyde emission level on the adhesive system. Originality/value TCFR has been synthesised in the presence of a base catalyst. Environmental and ecological concerns have increased the attention paid by chemical industry to renewable raw materials.

INDIREKTE PAPIERCHROMATOGRAPHISCHE METHODE ZUR BESTIMMUNG DER HARNOESTROGENE

1961 ◽  
Vol 38 (4) ◽  
pp. 545-562 ◽  
Author(s):  
L. Kecskés ◽  
F. Mutschler ◽  
I. Glós ◽  
E. Thán ◽  
I. Farkas ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Granulosa Cell ◽  
Iron Content ◽  
List Type ◽  
Granulosa Cell Tumour ◽  
Hydrolysis Of ◽  
Phenol Fraction ◽  
Qualitative Determination

ABSTRACT 1. An indirect paperchromatographic method is described for separating urinary oestrogens; this consists of the following steps: acidic hydrolysis, extraction with ether, dissociation of phenol-fractions with partition between the solvents. Previous purification of phenol fraction with the aid of paperchromatography. The elution of oestrogen containing fractions is followed by acetylation. Oestrogen acetate is isolated by re-chromatography. The chromatogram was developed after hydrolysis of the oestrogens 'in situ' on the paper. The quantity of oestrogens was determined indirectly, by means of an iron-reaction, after the elution of the iron content of the oestrogen spot, which was developed by the Jellinek-reaction. 2. The method described above is satisfactory for determining urinary oestrogen, 17β-oestradiol and oestriol, but could include 16-epioestriol and other oestrogenic metabolites. 3. The sensitivity of the method is 1.3–1.6 μg/24 hours. 4. The quantitative and qualitative determination of urinary oestrogens with the above mentioned method was performed in 50 pregnant and 9 non pregnant women, and also in 2 patients with granulosa cell tumour.

Simultaneous Spectrophotometric Determination of Salbutamol by Coupling with Diazotized 4-Aminobenzoic acid

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Hind Hadi ◽  
Gufran Salim
Keyword(s):  
Pharmaceutical Preparations ◽  
Coupling Reaction ◽  
Dosage Forms ◽  
Water Soluble ◽  
Trace Determination ◽  
Aminobenzoic Acid ◽  
Optimum Conditions ◽  
Colored Product ◽  
Versus Concentration

A simple, rapid and sensitive spectrophotmetric method for trace determination of salbutamol (SAL) in aqueous solution and in pharmaceutical preparations is described. The method is based on the diazotization coupling reaction of the intended compound with 4-amino benzoic acid (ABA) in alkaline medium to form an intense orange, water soluble dye that is stable and shows maximum absorption at 410 nm. A graph of absorbance versus concentration indicates that Beer’s law is obeyed over the concentration range of 0.5-30 ppm, with a molar absorbtivity 3.76×104 L.mol-1 .cm-1 depending on the concentration of SAL. The optimum conditions and stability of the colored product have been investigated and the method was applied successfully to the determination of SAL in dosage forms.

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