About the plausible contribution of field ionization in the mechanism of the formation of dyes of ions under conditions of laser desorption/ionization from a nanostructurized graphite surface

Shelkovskii, V. S.; Kosevich, M. V.; Chagovets, Vitaliy; Boryak, Oleg A.; Orlov, V. V.; Snegir, Sergii; Shmigol, I. V.; Pokrovskii, V. A.

doi:10.1134/s1061934810130137

Cited by 4 publications

(4 citation statements)

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“…On the basis of the experiments performed with imidazophenazine derivatives of some dyes, it was demonstrated that the efficiency of the dye reduction under the LDI conditions decreases in the following series of systems: a crystalline mixture of a dye with redoxactive 2,5-dihydroxybenzoic acid (used as an organic matrix in matrix-assisted LDI 43 ), a thin layer of a dye on the bare metal surface, and a film of a dye on a nanostructured graphite surface. 32,44 The reduction reaction was completely suppressed in the presence of nitrobenzyl alcohol, which is an electron scavenger. 45 Since the reduction reactions of a dye molecule stimulated by external exciting agents require a source of electrons and protons, a necessary condition for the dye reduction is the existence of dye molecules in the form of intermolecular complexes (e.g., dimers) 46 or to be in contact with other redoxactive organic molecules.…”

Section: Resultsmentioning

confidence: 99%

“…The efficiency of the reduction reaction was estimated from the increase of the abundance of the reaction products. On the basis of the experiments performed with imidazophenazine derivatives of some dyes, it was demonstrated that the efficiency of the dye reduction under the LDI conditions decreases in the following series of systems: a crystalline mixture of a dye with redox-active 2,5-dihydroxybenzoic acid (used as an organic matrix in matrix-assisted LDI), a thin layer of a dye on the bare metal surface, and a film of a dye on a nanostructured graphite surface. , The reduction reaction was completely suppressed in the presence of nitrobenzyl alcohol, which is an electron scavenger …”

Section: Resultsmentioning

confidence: 99%

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Noncovalent Interaction of Methylene Blue with Carbon Nanotubes: Theoretical and Mass Spectrometry Characterization

et al. 2012

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Noncovalent interaction of methylene blue dye cation (MB + ) with single walled carbon nanotubes (CNT) is characterized by molecular dynamics (MD) simulation, quantum chemical calculations, and laser desorption/ionization (LDI) mass spectrometry. The MD simulation of the (MB + ) n −CNT (n = 1−10) complexes in water demonstrates that the MB + cations are adsorbed on the nanotube surface in the monomeric form. MD reveals both parallel and perpendicular orientations of the MB + tricyclic plane in relation to the long axis of CNT when placed in the water environment. The interaction energy between the components of the complex in the perpendicular conformation, as determined by quantum chemical calculations at the DFT/M05-2X/6-31++G(d,p) level of theory, explains why the bending of the MB + cation at the sulfur atom weakens the π-system of bonds and allows for the perpendicular orientation to occur. It is also found that the adsorbed MB + induces positive electrostatic potential around the adjacent semicylindrical segment of the nanotube. The mainly monomolecular adsorption of the MB + cations at the CNT surface leads to the absence in the LDI mass spectra of (MB + ) n −CNT of features corresponding to products of the reduction of MB + commonly observed in the LDI mass spectra of crystalline dyes.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Noncovalent Interaction of Methylene Blue with Carbon Nanotubes: Theoretical and Mass Spectrometry Characterization

et al. 2012

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“…Рязанова, В.А. Пашинская процессов ПИ и ПД в механизм генерации ионов при ЛДИ с наноструктурированных графитовых поверхностей [34].…”

Section: четырехциклические производные феназинаunclassified

Biophysical investigations of molecular mechanisms of chemotherapeutic agents action. 1. Chemotherapeutic and antiviral agents (Review)

2019

Biophysical Bulletin

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Background: Determination of molecular mechanisms of action of drugs forms a scientific basis for the directed search of efficient medications. Assumed pathways of interactions of chemotherapeutic drugs which affect infectious agents and malignant neoplasm with their potential molecular targets require direct evidences at the molecular level. Such evidences can be obtained by means of molecular biophysics which possesses an arsenal of new powerful physical techniques for studying the intermolecular interactions of biomolecules and pharmaceutical agents. Objectives: The aim of this review is the generalization of the results of long standing investigations on the molecular mechanisms of action of chemotherapeutic agents performed in the biophysical departments of B. Verkin Institute for Low Temperature Physics and Engineering (ILTPE) of the NAS of Ukraine. The first part of the review is devoted to anticancer and antiviral agents targeted presumably at nucleic acids. Materials and methods: Mass spectrometric studies of molecules of thermally unstable drugs and their complexes with biomolecules have been advanced significantly due to the development of soft ionization/desorption techniques; the researchers of ILTPE have made noticeable contribution to this field. The methods of molecular spectroscopy and computer modeling by means of quantum chemistry were applied in the combined investigations. Results: The objects of study were the systems composed of chemotherapeutic drugs – thiophosphamide, phenazine derivatives and phenazine-modified antigene/antisense oligonucleotides, quaternary compounds, tilorone – and their molecular targets – DNA, oligo- and polynucleotides and nucleic acids components. The mechanisms of action of these drugs established at the model molecular level consisted in the specific and nonspecific noncovalent or covalent interactions of the drugs’ molecules with nucleic acids and their components and in the formation of stable drug-target complexes. Conclusions: The experience of investigations conducted during several decades at the ILTPE has demonstrated the efficiency of the application of the methods and approaches of molecular biophysics to establishing of molecular mechanisms of drugs action. The basic results obtained are of practical importance for the further development of new efficient pharmaceuticals.

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“…27 Moreover, mass spectrometry can also monitor the way how the interactions of dyes with their environment inuence the reduction rate. [28][29][30][31][32] On this basis we have formulated a mass spectrometric approach to the observation of changes in reduction of dyes in dependence of experimental conditions, aimed at modeling and studying reduction and oxidation processes in nanostructures. This approach was successfully applied to the study of the form of MB adsorption on carbon nanotubes (CNT) surface.…”

Section: Introductionmentioning

confidence: 99%

Monomer/dimer dependent modulation of reduction of the cationic dye methylene blue in negatively charged nanolayers as revealed by mass spectrometry

et al. 2014

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The possibility to control the reduction rate of redox-active dyes incorporated into nanostructures is of interest for nanotechnology and biomedicine. We propose a novel mass spectrometric approach to study the aggregation-dependent modulation of cationic dye methylene blue (MB) reduction in the case of its inclusion into negatively charged nanolayers, which is based on detecting the difference in the redox activity of monomers and dimers of the MB cation (Cat + ). A regular reproducible recording of either intact Cat + in the case of MB present in its monomeric form, or one-and two-electron reduction products [Cat + H] + c and [Cat + 2H] + in the case of MB dimer formation, is observed for three different anionic nanostructures with varied content of MB, tested by three mass spectrometric methods: (1) an anionic surfactant sodium dodecyl sulfate (SDS) monolayer with adsorbed MB cations at the liquid-gas interface, probed by fast atom bombardment; (2) dried shells of soap bubbles blown from an SDS and MB aqueous solution, tested by laser desorption/ionization; (3) a nanotextured surface of porous silicon modified by -SO 3 À groups with adsorbed MB cations, studied by a desorption/ionization on silicon technique. The requirement for MB cations to be in the form of dimers or higher aggregates for reduction to be observed under mass spectrometric conditions is justified for the listed systems, where only another MB cation can serve as a source of the electrons and protons (or hydrogen radical Hc) necessary for reduction reaction. The proposed method can be applied to mass spectrometric imaging of stained biological materials, supplying information not only about the localization, but also the MB aggregation state as well.

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About the plausible contribution of field ionization in the mechanism of the formation of dyes of ions under conditions of laser desorption/ionization from a nanostructurized graphite surface

Cited by 4 publications

References 25 publications

Noncovalent Interaction of Methylene Blue with Carbon Nanotubes: Theoretical and Mass Spectrometry Characterization

Noncovalent Interaction of Methylene Blue with Carbon Nanotubes: Theoretical and Mass Spectrometry Characterization

Biophysical investigations of molecular mechanisms of chemotherapeutic agents action. 1. Chemotherapeutic and antiviral agents (Review)

Monomer/dimer dependent modulation of reduction of the cationic dye methylene blue in negatively charged nanolayers as revealed by mass spectrometry

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