National Repository of Grey Literature 23 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Electropolymerization of Methylene Blue on Highly Oriented Pyrolytic Graphite and Characterization of Deposited Film
Zlámalová, Magda ; Janda, Pavel ; Nesměrák, K.
This work presents the investigation of methylene blue (MB) polymerization as well as characterization of deposited conductive film on basal plane highly oriented pyrolytic graphite (HOPG) substrate. Poly(methylene blue) modified HOPG electrodes (HOPG/pMB) have been prepared by potential cycling in aqueous electrolyte solution containing monomer methylene blue. Atomic force microscopy (AFM) has been used for the nanomorphological study of immobilized poly(methylene blue) film.
Use of Monovalent Copper for Sensitive Detection of Methyl Derivatives of Xanthine
Navrátil, R. ; Motlova, D. ; Jelen, F. ; Trnková, L.
This work is concerned with the electroanalysis of xanthine (Xan) and its methylated derivatives (1-, 3-, 7-, and 9-mXan) on a pencil graphite electrode in the presence of copper ions. The main idea of using copper consists in the in situ formation of the complex Cu(I)-mXan on the electrode surface and improvement of oxidative signals of the corresponding mXan during the detection. Linear sweep voltammetry (LSV) in connection with adsorption stripping techniques was used for the determination of mXan. To enhance the oxidation signals the elimination voltammetric procedure (EVP) was applied.
A Preliminary Study of Modification of 7-Deazaadenine with a Complex of Osmium Tetroxide with 2,2 '-Bipyridine
Vítová, Lada ; Havran, Luděk ; Fojta, Miroslav ; Šedo, O. ; Zdráhal, Z. ; Vespalec, Radim
Reactivity of a purine nucleic base analogue 7-deazaadenine (A*) in short oligodeoxynucleotide (ODN) towards an osmium tetroxide complex with 2,2'-bipyridine (Os, bipy) was investigated by means of electrochemistry, capillary electrophoresis and MALDI-TOF mass spectrometry. Electrochemical measurement, electrophoretic analyses and mass spectrometric analyses of reaction mixture proved that ODN with an A* residue yields an osmium adduct with properties similar to those exhibited by the well-known adduct of thymine.
Enzymatic Incorporation of Biotin into DNA for DNA Hybridization Analysis and for Sensitive Detection of PCR-Amplified DNA
Špaček, Jan ; Zenka, Martin ; Haroniková, Lucia ; Havran, Luděk ; Fojta, Miroslav
We present two enzymatical electrochemical assays for DNA analysis. For hybridization analysis we used probes with biotin-14-dC introduced to 3' OH end by terminal transferase. For detection of PCR products we used Deep Vent polymerase to incorporate biotin-14-dCduring PCR. In both cases streptavidin-alkaline phosphatase conjugate was subsequently attached to the incorporated biotins and was used to catalyze dephosphorylation of 1-naphthyl phosphate to 1-naphthol, the electrochemical signal of which was utilized for detection. Compared to the former method, biotin incorporation during PCR offers lower molar detection limits, whereas application of the biotin-tailed probe can provide us with more selective detection.
Detection of Single Nucleotide Polymorphisms Using Selective Incorporation of Biotin in DNA Strand and Subsequent Enzymatic Detection at Pencil Electrode
Plucnara, Medard ; Ecsin, E. ; Erdem, A. ; Fojta, Miroslav
Enzyme-linked electrochemical assay using DNA labeling by biotin followed by binding of enzyme-streptavidin conjugates has been found to be a potent tool for DNA diagnostic. This approach brings a special advantage of signal amplification due to the fact, that only very small number of enzymatic labels can produce a number of molecules of an electrochemically detectable product from an inactive substrate to obtain sufficiently strong signal. A new way of using of this technique combined with selective primer extension reaction designed for the detection of single nucleotide polymorphism is presented here. The assay was combined with measurements at a pencil graphite electrode, which is a very practical tool for potential clinical applications due to its cheapness and disposability.
Electrochemical Detection of p53 Protein Interactions with Plasmid DNAs Modified with Cisplatin Using Immunoprecipitation at Magnetic Microbeads
Pivoňková, Hana ; Tichý, Vlastimil ; Orság, Petr ; Šebest, Peter ; Fojta, Miroslav
Antineoplastic drug [cis-diamminedichloroplatinum(II)] (cisplatin) forms covalent adducts with DNA. Cisplatin-modified DNA can be determined sensitively using square-wave voltammetry at mercury electrodes. Tumor suppressor protein p53 binds to DNA in different modes, including sequence-and structure-specific ones and these interactions are influenced by modification of the DNA with cisplatin. In this contribution we present a simple immunoprecipitation technique with magnetic beads, followed by voltammetric determination of recovered cisplatinated DNA, for the evaluation of p53 protein binding to DNAs containing various target sites differing in their proneness to being internally modified with the platinum complex.
Application of Cyclopentenediones for Preparation of Permselective Layers.
Vacek, J. ; Hrbáč, J. ; Matějka, P. ; Storch, Jan
In this contribution, we report that electrooxidation of PCD, phenolic cyclopentenedione, 2,2'-bis[4,5-bis(4-hydroxybenzyl)-2-(4-hydroxyphenyl)-cyclopent-4-ene-1,3-dione] results in the formation of stable films with permselective properties on metal and carbon surfaces. The electropolymerization process proceeds in neutral and alkaline aqueous medium at potentials higher than +0.6 V (vs. Ag/AgCl/3M KCl). The PCD polymer prepared was characterized by electrochemical methods, quartz crystal microbalance and optical spectroscopy techniques. The PCD film can be used for electrode coating and preparation of an anti-interference barrier. Thus, we performed SAR study which could open the door to developing novel functional films and electrochemical tools for bioactive compounds sensing.\n
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Searching for Electrochemical Reduction Mechanism of Azidophenyl DNA Labels
Daňhel, Aleš ; Trošanová, Zuzana ; Balintová, Jana ; Hocek, Michal ; Fojta, Miroslav
This contribution brings new information to sporadic scientific results concerned to electrochemical reduction of aromatic azides. Selected compounds used as perspective DNA labels or their structural constituents such as, 4-azidophenyltrifluoroboronic acid, 4-azidophenyl modified deoxycytidine and next probable analogous compounds and/or products of their reduction, were voltammetrically studied and compared to each other in order to reveal a mechanism of their electrochemical reduction at mercury electrodes in aqueous media. Preliminary results obtained by cyclic voltammetry at mercury and carbon based electrodes and by mass spectrometry of the products isolated from batch electrolysis on mercury pool by preparative chromatography are discussed.
Voltammetric Analysis of Anthraquinone-labeled Nucleotide Triphosphates and Oligonucleotides at Gold Electrodes
Vidláková, Pavlína ; Balintová, Jana ; Havran, Luděk ; Hocek, Michal ; Fojta, Miroslav
DNA labelling is used for increase of sensitivity of electrochemical detection. When the DNA or oligonucleotides (ONs) are chemically modified, their electrochemical responses can be changed depending on electrochemical activity of the introduced moiety. One option of DNA labeling is incorporation of chemically modified nucleotides using corresponding deoxynucleotide triphosphates (dNTPs) into DNA molecules with using primer extension (PEX). In our study we used anthraquinone labeled dNTPs and ONs with enzymatically incorporated anthraquinone labeled nucleotides. Thus synthesized ON stretch bearing the anthraquinone tags was electrochemically analyzed using voltammetry at gold electrodes.
Voltammetric Behavior of 4-Aminophthalimide Label using Hanging Mercury Drop Electrode
Ferenčíková, Z. ; Daňhel, Aleš ; Riedl, Jan ; Hocek, Michal ; Fojta, Miroslav
4-aminophthalimide (API), covalently attached to nucleotide (dCTP or dATP) has recently beendesigned as a fluorescent label for the detection of DNA-protein interaction. However API is electrochemically reducible and therefore it is possible to use alternatively the API-modified nuclotides as DNA redox labels. The electrochemical behavior of labeled nucleotides and labeled DNA was studied using cyclic voltammetry and transfer stripping cyclic voltammetry at hanging mercury drop electrode. Observed CVs showed irreversible reduction signals of 4-aminophthalimide label without production of consequently oxidizable/reducible species.

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