Homogeneous enzyme-free and entropy-driven isothermal fluorescent assay for nucleic acids based on a dual-signal output amplification strategy

2018 ◽  
Vol 54 (89) ◽  
pp. 12594-12597 ◽  
Author(s):  
Erhu Xiong ◽  
Deshuai Zhen ◽  
Ling Jiang
Keyword(s):  
Nucleic Acids ◽  
Reaction Rate ◽  
Analytical Performance ◽  
Fluorescent Assay ◽  
Mismatched Dna ◽  
Fluorescent Biosensor ◽  
Dna Strands ◽  
Signal Output ◽  
Amplification Strategy

The proposed fluorescent biosensor improves the reaction rate, has excellent analytical performance (LOD 15.6 fM) and shows outstanding recognition toward mismatched DNA strands. This approach provides a potential universal platform for the determination of other nucleic acids.

A new photoelectrochemical biosensor for ultrasensitive determination of nucleic acids based on a three-stage cascade signal amplification strategy

The Analyst ◽  
2018 ◽  
Vol 143 (12) ◽  
pp. 2799-2806 ◽  
Author(s):  
Erhu Xiong ◽  
Xiaoxia Yan ◽  
Xiaohua Zhang ◽  
Yanmei Li ◽  
Ruiying Yang ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Signal Amplification ◽  
Dna Detection ◽  
Amplification Method ◽  
Photoelectrochemical Biosensor ◽  
Amplification Strategy

Based on a “signal-on” sensing strategy and a three-stage cascade signal amplification method, an ultrasensitive photoelectrochemical biosensor has been developed for DNA detection.

A novel fluorescent assay for uracil DNA glycosylase activity built on the 3′–5′ exonuclease activity-based endonuclease IV cyclic signal amplification strategy

2020 ◽  
Vol 44 (48) ◽  
pp. 21211-21217
Author(s):  
Jing-Xuan Tian ◽  
Yan-Zhao Fang ◽  
Yi-Xuan Yang ◽  
Shuang Wu ◽  
Qiang Xiao ◽  
...  
Keyword(s):  
Signal Amplification ◽  
Dna Glycosylase ◽  
Exonuclease Activity ◽  
Sensitive Assay ◽  
Fluorescent Assay ◽  
Uracil Dna Glycosylase ◽  
Highly Sensitive ◽  
Dna Strands ◽  
Amplification Strategy

The unique 3′-5′ exonuclease activity of endonuclease IV to DNA strands has been demonstrated, which enables the development of a novel highly sensitive assay for UDG activity.

Alcohol Determination by HPLC with Postcolumn Derivatization Based on the Thiosulfate-catalyzed Reaction of Alcohols and Cerium(IV) and Fluorescence Detection of Cerium(III)

2020 ◽  
Vol 16 ◽  
Author(s):  
Ikko Mikami ◽  
Eri Shibayama ◽  
Kengo Takagi
Keyword(s):  
Detection Limit ◽  
Fluorescence Detection ◽  
Reaction Rate ◽  
Detection Method ◽  
Fluorescence Detector ◽  
Reaction Solution ◽  
Optimum Detection ◽  
Postcolumn Derivatization ◽  
Sensitive Method

Background: Determination of a reducing substance based on the reaction between Ce(IV) and a reducing substance and fluorescence detection of Ce(III) generated has been reported as a selective and sensitive method. However, this method could not be applied to the determination of alcohol due to the low reaction rate of alcohol and Ce(IV). Objective: We found that thiosulfate catalytically enhanced reaction of alcohols (such as, methanol, ethanol, and propanol) and Ce(IV). Utilizing this effect, we developed a new method for the determination of alcohols. Results: In the presence of thiosulfate, an increase in fluorescence intensity was detected by injecting alcohol at concentrations of several millimolar, whereas it was not observed even at the concentration of 10% v/v (2 M for ethanol) in the absence of thiosulfate. The optimum detection conditions were determined to be 4.0 mM Ce(IV) sulfate and 0.50 mM thiosulfate, and the detection limit (S/N = 3) of ethanol under these conditions was 1 mM. In the calibration curves, changes in the slope were observed when the alcohol concentrations were approximately 10–25 mM. Using a thiosulfate solution containing ethanol as the reaction solution, a calibration curve without any change in slope was obtained, although the concentration of ethanol at the detection limit increased. The alcohols in the liquor and fuel were successfully analyzed using the proposed detection method as a postcolumn reaction. Conclusion: This new alcohol detection method using a versatile fluorescence detector can be applied to the postcolumn reaction of HPLC omitting need of time-consuming pretreatment processes.

Kinetics and mechanism of redox reactions of U(III) ions with monochloroacetic and dichloroacetic acids

1979 ◽  
Vol 44 (2) ◽  
pp. 401-405 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Ľudovít Treindl
Keyword(s):  
Redox Reactions ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Outer Sphere ◽  
Alcohol Concentration ◽  
Kinetics And Mechanism ◽  
Solvent Structure ◽  
Influence Of Ph ◽  
Sphere Mechanism

The kinetics and mechanism of the redox reactions of U3+ ions with mono- and dichloroacetic acids were studied. The influence of pH was observed mainly in the second case and led to the determination of the rate constants and activation parameters corresponding to two parallel steps, namely oxidation of U3+ with CHCl2COO- ions and oxidation of U3+ with CHCl2.COOH molecules. The influence of binary mixtures of water with methanol, ethanol, isopropanol, or tert-butenol on the reaction rate was followed. Increasing alcohol concentration influences the rate constant not only through changing dielectric constant and solvation of the reactants but also through a change of the solvent structure which plays a role in reactions with an outer sphere mechanism of the electron transfer.

Decomposition of peroxobenzoic acid in benzene catalyzed by transition metal 2,4-pentanedionates

1984 ◽  
Vol 49 (3) ◽  
pp. 673-679 ◽  
Author(s):  
Pavel Lederer ◽  
Eva Mácová ◽  
Josef Vepřek-Šiška
Keyword(s):  
Transition Metal ◽  
Reaction Rate ◽  
Reaction Products ◽  
Acid Decomposition ◽  
Analogous Experiment ◽  
Catalytic Effects

The decomposition of peroxobenzoic acid in benzene was studied, and catalytic effects of Fe(III), Mn(III), Co(II), Co(III), and Cr(III) on the reaction rate and the composition of the reaction mixture were investigated. An analogous experiment carried out in perdeuterobenzene and determination of the distribution of deuterium in the reaction products provided evidence for the participation of the solvent in peroxobenzoic acid decomposition.

Determination of the binding site size of hexaammineruthenium(iii) inside monolayers of DNA on gold

The Analyst ◽  
2021 ◽  
Author(s):  
Alireza Abi ◽  
Afsaneh Safavi
Keyword(s):  
Metal Complex ◽  
Binding Site ◽  
Dna Strands

Hexaammineruthenium(iii) metal complex can bind to surface-tethered DNA strands in excess of what is required for the compensation of the DNA charges.

scholarly journals A Magnetic Nanocomposite Modifier for Improved Ultrasensitive Detection of Hexavalent Chromium in Water Samples

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 189
Author(s):  
Nuša Hojnik ◽  
Olivija Plohl ◽  
Matjaž Finšgar
Keyword(s):  
Electron Microscopy ◽  
Analytical Performance ◽  
Magnetic Nanocomposite ◽  
Ex Situ ◽  
Trace Determination ◽  
Silica Layer ◽  
X Ray ◽  
Square Wave ◽  
Static Contact

In this work, different electrodes were employed for the determination of Cr(VI) by the cathodic square‑wave voltammetry (SWV) technique and the square-wave adsorptive stripping voltammetry (SWAdSV) technique in combination with diethylenetriaminepentaacetic acid. Using SWV, a comparison of the analytical performance of the bare glassy carbon electrode (GCE), ex situ electrodes (antimony-film—SbFE, copper-film—CuFE, and bismuth-film—BiFE), and the GCE modified with a new magnetic nanocomposite (MNC) material was performed. First, the MNC material was synthesized, i.e., MNPs@SiO2@Lys, where MNPs stands for magnetic maghemite nanoparticles, coated with a thin amorphous silica (SiO2) layer, which was additionally functionalized with derived lysine (Lys). The crystal structure of the prepared MNCs was confirmed by X-ray powder diffraction (XRD), while the morphology and nano-size of the MNCs were investigated by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), where TEM was additionally used to observe the MNP core and silica layer thickness. The presence of functional groups of the MNCs was investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and surface analysis was performed by X-ray photoelectron spectroscopy (XPS). The hydrophilicity of the modified electrodes was also tested by static contact angle measurements. Then, MNPs@SiO2@Lys was applied onto the electrodes and used with the SWV and SWAdSV techniques. All electrodes tested with the SWV technique were effective for Cr(VI) trace determination. On the other hand, the SWAdSV technique was required for ultra-trace determination of Cr(VI). Using the SWAdSV technique, it was shown that a combination of ex situ BiFE with the deposited MNPs@SiO2@Lys resulted in excellent analytical performance (LOQ = 0.1 µg/L, a linear concentration range of 0.2–2.0 µg/L, significantly higher sensitivity compared to the SWV technique, an RSD representing reproducibility of 9.0%, and an average recovery of 98.5%). The applicability of the latter system was also demonstrated for the analysis of a real sample.

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