Head of the laboratory of chemistry for organo-mineral materials
Department of analytical chemistry Taras Shevchenko
National University of Kyiv
60 Vladimirskaya Str., Kiev Ukraine 01601
D.Sc., PhD, Corr. member of Acad. of Sci. of Ukraine
Phenylboronic-Acid-Modified Nanoparticles: Potential Antiviral Therapeutics
ACS Appl. Mater. Interfaces, 2013, 5 (23), p. 12488–12498
DOI: 10.1021/am403770q
Phenylboronic-acid-modified nanoparticles (NPs) are attracting considerable attention for biological and biomedical applications. We describe here a convenient and general protocol for attaching multiple copies of-substituted phenylboronic acid moieties onto either iron-oxide-, silica- or diamond-derived NPs. The boronic acid functionalized NPs are all fabricated by first modifying the surface of each particle type with 4-azidobenzoic ester functions. These azide-terminated nanostructures were then reacted with 4-[1-oxo-4-pentyn-1-yl) amino]phenylboronic acid units via a Cu(I) catalyzed Huisgen cycloaddition to furnish, conveniently, the corresponding boronic-acid modified NPs (or “borono-lectins”) targeted in this work. The potential of these novel “borono-lectins” as antiviral inhibitors was investigated against the Hepatitis C virus (HCV) exploiting a bioassay that measures the potential of drugs to interfere with the ability of cell-culture-derived JFH1 virus particles to infect healthy hepatocytes. As far as we are aware, this is the first report that describes NP-derived viral entry inhibitors and thus serves as a “proof-of-concept” study. The novel viral entry activity demonstrated, and the fact that the described boronic-acid-functionalized NPs all display much reduced cellular toxicities compared with alternate NPs, sets the stage for their further investigation. The data supports that NP-derived borono-lectins should be pursued as a potential therapeutic strategy for blocking viral entry of HCV.
Electrophoretic deposition of macroporous carbon nanotube assemblies for electrochemical applications
CARBON, v.53 (2013), p.302 –312
Electrophoretic deposition of macroporous assemblies of single-walled carbon nanotubes (SWCNTs) is described. The macroporous structure was created thanks to the presence of polystyrene (PS) beads which were co-deposited with the carbon nanotubes in a 60 V potential field. The ratio between the quantity of carbon nanotubes and polystyrene beads in the solution for deposition was found to be critical for the proper self-assembly of the composite film during electrophoretic deposition. The macroporous films have been characterized by scanning electron microscopy, atomic force microscopy and profilometry. The macroporosity was revealed after template removal (calcination of the PS beads). Access to the internal surface was assessed by electrochemical characterization using methylene green as a redox probe likely to adsorb on the SWCNT surface. Platinum nanoparticles and a sol–gel layer with encapsulated dehydrogenase and NAD+ cofactor have been deposited on the macroporous SWCNT electrodes in order to illustrate the use of the macropore texture for the detection of H2O2 and for biosensor applications, respectively.
Iron Oxide Magnetic Nanoparticles with Versatile Surface Functions Based on Dopamine Anchors
Nanoscale, 2013, v.5, p.2692-2702
DOI: 10.1039/c3nr33506b
The synthesis of multifunctional magnetic nanoparticles (MF-MPs) is one of the most active research areas in advanced materials as their multifunctional surfaces allow conjugation of biological and chemical molecules, thus making it possible to achieve target-specific diagnostic in parallel to therapeutics. We report here a simple strategy to integrate in a onestep reaction several reactive sites onto the particles. The preparation of MF-MPs is based on their simultaneous modification with differently functionalized dopamine derivatives using simple solution chemistry. The formed MF MPs show comparable magnetic properties to those of naked nanoparticles with almost unaltered particle size of around 25 nm. The different termini, amine, azide and maleimide functions, enable further functionalization of MF MPs by the grafting-on approach. Michael addition, Cu(I) catalyzed « click » chemistry and amidation reactions are performed on the MF MPs integrating subsequently 6-(ferrocenyl)-hexanethiol, horse radish peroxidase (HRP) and mannose.
Chromium(VI) removal via reduction-sorption on bi-functional silica adsorbents
Journal of Hazardous Materials 250– 251 (2013) pp. 454– 461
Abstract: Organically-modified silica gels bearing mercaptopropyl and ethylenediaminetriacetate groups (SiO2-SH/ED3A) have been used for reduction and subsequent sequestration of Cr(VI) species. The uptake mechanism involves Cr(VI) reduction by thiol groups (SH) and further immobilization of the so-generated Cr(III) species via complexation to the ethylenediaminetriacetate moieties (ED3A). The most appropriate pH range (1-3) for complete Cr(VI) reduction-sorption by SiO2-SH/ED3A originates from the balance between full reduction of Cr(VI) by SH, requiring low pH values, and quantitative complexation of Cr(III) by ED3A, which is favored in less acidic media. Such bi-functional adsorbents are considerably more effective at removal of Cr(VI) than those simply modified with thiol groups alone. The whole reductionsorption process was characterized by fast kinetics, thus permitting efficient use of the SiO2-SH/ED3A adsorbent in dynamic conditions (column experiments). Monitoring the amount of immobilized chromium species on the solid was achieved using X-ray fluorescence spectroscopy and UV-Vis spectroscopy. Studying the influence of ionic strength and presence of heavy metals revealed few interference on Cr(VI) removal.
Characterization of MCM-41 with Immobilized Bi-functional SH/SO3H Layer
J. Inorg. Organomet. Polym. (2013) 23:1409–1416
DOI 10.1007/s10904-013-9943-5
A new approach for quantitative determination of –SHand –SO3Hfunctional groups onMCM-41 silica with covalently immobilized mercaptopropyl groups is proposed. A set of MCM-41 type samples containing 1 mmol g-1 of mercaptopropyl groups was oxidized with proportional quantities of hydrogen peroxide and subsequently characterized with different ratios of grafted mercaptopropyl and propylsulfonic acid groups. Data calculated from conductometric titration were correlated with the corresponding X-ray photoelectron spectra and exhibit a linear relationship of results for both techniques. The described method was applied to thiol-containing MCM-41 samples to reveal ambient oxidation of organo-silicas with immobilized thiol groups.
Valentina Levchik, Tatiana Fomenko, Maryna Zui, Vladimir Zaitsev
DISPERSIVE MICROEXTRACTION FOR THE GC ANALYSIS OF SOME ENDOCRINE DISRUPTORS
Med Data Rev 2013, v. 5 №1, pp. 15-18.
The determination of microamounts of benzophenones in water and human urine samples using miniaturized dispersive liquid-liquid microextraction and GC–FID was described. The calibration curve for benzophenones is linear with correlation coefficient higher than 0.996 in the range 0,05–0,50 µg/mL. The average recoveries of benzophenones in human urine samples spiked with 0,1 and 0,2 µg/mL of key analytes are 85–104% (RSD: 2,7–12.3%) respectively. The detection limit and the quantification limit of benzophenones in human urine samples were 5-10 and 40–50 ng/mL, respectively
Визначення метилпарабену та пропілпарабену в сиропах медичного призначення різного компонентного складу із застосуванням методу ВЕРХ
Укр. хим. журн., 2013, № 2, c.102-107
A novel reversed-phase LC method using CN-propyl column has been developed and validated for the analysis of methylparaben and propylparaben in medical syrups of different composition. The chromatographic separation was achieved by HPLC using a mixture of 0,1 % orthophosphoric acid solution in water with acetonitrile as the mobile phase, a Discovery Cyano column and UV detection at 254nm. The method was validated with respect to linearity, precision, accuracy, selectivity. All the charesteristics examined met the current recommendations for HPLC method validation. The method was successfully used for determining both compounds in 8 medical syrups of different composition.
Розроблено і валідовано нову методику визначення метилпарабену та пропілпарабену в сиропах медичного призначення різного складу з використанням методу обернено-фазної хроматографії на цианопропільній нерухомій фазі. Хроматографічне розділення досягнуто з використанням суміші 0,1 % ортофосфорної кислоти в воді і ацетонітрилу, як рухомої фази, колонки Discovery Cyano і спектрофотометричної детекції при довжини хвилі 254 нм. Розроблена методика дозволяє зменшити вміст органічного розчинника у рухомій фазі в 4-6 рази, та проводити визначення аналізу за 3 хв. При проведенні валідації було перевірено лінійність, придатність системи, придатність методу, правильність, селективність. Метод був успішно використаний для визначення обох сполук в 8 сиропах медичного призначення.
Визначення ментолу у льодяниках "Травісил”
Вісник Київського національного університету імені Тараса Шевченка. Хімія, 2013, т. 49, № 1, c.35-38
Menthol - cyclic terpene alcohol , which is produced synthetically or extracted from mint essential oils. Due to its anesthetic, antiseptic properties, very low toxicity ( LD50 lethal dose at equal intake of 350 mg / kg and in contact with skin 3300 mg / kg ), it is widely used in pharmaceutical preparations as a flavoring in food industry, in the production of cosmetics. Today in Ukraine drugs undergo significant fraud. Specified on the packaging of pharmaceutical composition is not true. As a result, their use sometimes results in the desired effect. Therefore, control of the content of the components of drugs is an important task , both for producers and for consumers. For example, there is no uniform methods of sample preparation in the quantitative determination of menthol , but wrong contents of components often associated with errors that occur at this stage of analysis. The liquid-liquid extraction today remains the most affordable and the most common method of sample preparation in the analysis of menthol for most laboratories The purpose of the work was to develop a technique of liquid-liquid extraction of menthol candies "Travisyl" and its subsequent chromatographic determination. Conditions of the liquid- liquid extraction and gaschromatography analysis of the menthol in the candies “Travisil” were optimized. Was found that menthol from aqueous solutions is best removed with hexane . Chromatographic separation occurs in isothermal mode on the HP- 5 column . Menthol content was calculated by the method of internal standard . On the whole operating range of concentrations relative standard deviation does not exceed 0.04, which correlates with the literature data. Chromatographic analysis time is 6 minutes. Samples of candies “Travisil” was analyzed in this conditions. Found menthol content in candies " Travisyl " than the data specified on the package (2 mg).
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Head of the laboratory of chemistry for organo-mineral materials Department of analytical chemistry Taras Shevchenko
National University of Kyiv |
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| tel: +380-97-0980693, e-mail: vnzaitsev@gmail.com, http://anchem.knu.ua/ua/main_ukr.html | |
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