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od 2020-09-20 |
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1. |
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Gemini surfactants based on bis-imidazolium alkoxy derivatives as effective agents for delivery of nucleic acids: A structural and spectroscopic study The success rate of gene therapy depends on the efficient transfection of genetic material into cells. The golden mean between harmlessness and high effectiveness can be provided by synthetic lipid-like molecules that are similar to the components of biological membranes. Cationic gemini surfactants are one such moiety and because of their favourable physicochemical properties (double positive electric charge, reduced toxicity, low values of critical micelle concentration), they show great potential as delivery system components for genetic material in gene therapy. The aim of this study was to investigate the process of the complexation of cationic gemini surfactants with nucleic acids: double-stranded DNA of different sizes (21 bp, ~185 bp, ~20 kbp) and siRNA (21 bp). The tested series of dicationic surfactants consists of bis-imidazolium quaternary salts with varying lengths of hydrophobic side chains (m = 5, 6, 7, 8, 9, 11, 12, 14, 16). On the basis of the data obtained by circular dichroism spectroscopy and electrophoresis, we concluded that the studied gemini surfactants with long side chains effectively bind nucleic acids at low concentrations, which leads to the formation of stable lipoplexes. Images obtained by atomic force microscopy also confirmed the formation of vesicular structures, i.e., complexes between DNA and surfactants. The cytotoxicity of selected surfactants was also tested on HeLa cells. The surfactant toxicity significantly depends on surfactant geometry (the length of hydrophobic chain).
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PloS ONE, 10(12), 1-22, (2015) |
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Adsorption of dimeric surfactants in lamellar silicates The adsorption of different types of cationic surfactants in lamellar silicates changes their surface character from hydrophilic to hydrophobic. This study was undertaken to obtain lamellar silicates modified by a series of novel dimeric (gemini) surfactants of different length alkyl chains and to characterise these organophilised materials. Synthetic sodium montmorillonite SOMASIF® ME 100 (M) and enriched bentonite of natural origin (Nanoclay - hydrophilic bentonite®) were organophilised with dimeric (gemini) surfactants (1,1′-(1,4-butanediyl) bis(alkoxymethyl)imidazolium dichlorides). As a result of surfactant molecule adsorption in interlamellar space, the d-spacing (d001) increased from 0.97 nm (for the anhydrous structure) to 2.04 nm. A Fourier transform infrared spectroscopy (FTIR) analysis of the modified systems reveals bands assigned to the stretching vibrations of the CH2 and CH3 groups and the scissoring vibrations of the NH group from the structure of the dimeric surfactants. Thermogravimetric (TG) and derivative thermogravimetric (DTG) studies imply a four-stage process of surfactant decomposition. Scanning electron microscopy (SEM) images provide information on the influence of dimeric surfactant intercalation into the silicate structures. Particles of the modified systems show a tendency toward the formation of irregularly shaped agglomerates.
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Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 364, 108-115, (2015) |
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Core-shell system based on titanium dioxide with elevated value of dielectric permittivity: Synthesis and characterization In this work we report a reproducible and efficient method of surface modification of titania nanoparticles (rutile) via reversible-deactivation radical polymerization. Herein, we graft poly(di (ethylene glycol) methyl ether methacrylate) from the surface of TiO2in an amount of 21 wt% within the reaction time of 3 h 15 min. The amount of grafted polymer was assessed by Thermogravimetric Analysis and it is one of the highest reported till now for this ceramic nanoparticles by atom transfer radical polymerization. The properties of inorganic-organic, i.e. core-shell material, as well as of pristine TiO2 and neat polymer were examined by Infrared and Dielectric Spectroscopies. The shape of the nanoparticles and the thickness of the polymer coating shell were investigated by means of High Resolution Transmission Electron Microscopy. The obtained nanocomposite exhibits dielectric permittivity e0= 18 and loss tangent around 1 102 at 20C. The described method allows controlling a length and chemical structure of the grafted polymer from ceramic core, thus to tailor a physical properties of nanoparticles and of nanocomposites.
(C) 2015 Elsevier B.V. All rights reserved. |
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Synthetic Metals, 209(3), 150-157, (2015) |
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4. |
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Magnetic and hydrophilic MWCNT/Fe composites as potential T-2-weighted MRI contrast agents In this work, functionalized Multiwall Carbon Nanotubes of specified length and containing well-defined iron particles (O-MWCNT/Fe) were prepared. A significant enhancement in contrast in Magnetic Resonance Imaging was found for the investigated composites. The magnetic characterization revealed the ferromagnetic nature of iron particles embedded within O-MWCNTs. The enhancement of the H-1 spin-spin relaxation time of MRI scans using hydrophilic O-MWCNT/Fe as potential contrast agents was estimated for selected dispersive media. Moreover, the cytotoxicity of the hybrids was studied in two cell lines, i.e. cancer cells (HeLa) and fibroblasts (GM07492). The intracellular impact of O-MWCNT/Fes in HeLa cells was observed after staining of selected organelles (nuclei and mitochondria). Significant changes in cell morphology were found for water soluble MWCNT/Fes with diameters above 30 nm. (C) 2015 Elsevier Ltd. All rights reserved.
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Carbon, 94, 1012-1020, (2015) |
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5. |
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Interaction of two imidazolium gemini surfactants with two model proteins BSA and HEWL Gemini surfactants and their interactions with proteins have gained considerable scientific interest, especially when amyloidogenic proteins are taken into account. In this work, the influence of two selected dicationic (gemini) surfactants (3,3'-[1,8-(2,7-dioxaoctane)]bis(1-dodecylimidazolium) chloride and 3,3'-[1,12-(2,11-dioxadodecane)]bis(1-dodecylimidazolium) chloride) on two model proteins, bovine serum albumin (BSA) and hen egg white lysozyme (HEWL), have been investigated. A pronounced and sophisticated influence on BSA structure has been revealed, including a considerable change of protein radius of gyration as well as substantial alteration of its secondary structure. Radius of gyration has been found to rise significantly with addition of surfactants and to fall down for high surfactants concentration. Similarly, a remarkable fall of secondary structure (alpha-helix content) has been observed, followed by its partial retrieval for high surfactants concentration. A strong aggregation of BSA has been observed for a confined range of surfactants concentrations as well. In case of HEWL-gemini system, on the other hand, the protein-surfactant interaction was found to be weak. Molecular mechanisms explaining such behaviour of protein-surfactant systems have been proposed. The differences of properties of both studied surfactants have also been discussed.
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Colloid and Polymer Science, 293(10), 2855-2866, (2015) |
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6. |
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Local motions in poly(ethylene-co-norbornene) studied by 1H NMR relaxometry Molecular motions in poly(ethylene-co-norbornene) were studied in a temperature range well below its glass transition point by a few techniques based on the NMR phenomenon. Temperature dependencies of proton spin-lattice relaxation times T1 (at 200 MHz and at 30.2 MHz), proton spin-lattice relaxation time in the rotating frame T1ρ (at 68 kHz) and frequency dispersion of proton spin-lattice off-resonance relaxation times in the rotating frame View the MathML source were determined for the copolymer. Analysis of 1H NMR relaxation data permitted characterization of local motions occurring in the copolymer i.e. rotation of methyl groups around C3 axes, reorientations of methylene groups and motions of segments of polymer chains including norbornene groups.
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Solid State Nuclear Magnetic Resonance, 71, 67-72, (2015) |
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7. |
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Synthesis and characterization of magnetite/silver/antibiotic nanocomposites for targeted antimicrobial therapy The article is devoted to preparation and characterization of magnetite/silver/antibiotic nanocomposites for targeted antimicrobial therapy. Magnetite nanopowder was produced by thermochemical technique; silver was deposited on the magnetite nanoparticles in the form of silver clusters. Magnetite/silver nanocomposite was investigated by XRD, SEM, TEM, AFM, XPS, EDX techniques. Adsorptivity of magnetite/silver nanocomposite towards seven antibiotics from five different groups was investigated. It was shown that rifampicin, doxycycline, ceftriaxone, cefotaxime and doxycycline may be attached by physical adsorption to magnetite/silver nanocomposite. Electrostatic surfaces of antibiotics were modeled and possible mechanism of antibiotic attachment is considered in this article. Raman spectra of magnetite, magnetite/silver and magnetite/silver/antibiotic were collected. It was found that it is difficult to detect the bands related to antibiotics in the magnetite/silver/antibiotic nanocomposite spectra due to their overlap by the broad carbon bands of magnetite nanopowder. Magnetic measurements revealed that magnetic saturation of the magnetite/silver/antibiotic nanocomposites decreased on 6-19% in comparison with initial magnetite nanopowder. Pilot study of antimicrobial properties of the magnetite/silver/antibiotic nanocomposites were performed towards Bacillus pumilus.
© 2015 Elsevier B.V. All rights reserved. |
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Materials Science & Engineering C - Materials for Biological Applications, 55, 343-359, (2015) |
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8. |
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Room temperature magnetism of few-nanometers-thick Fe3O4(111) films on Pt(111) and Ru(0001) studied in ambient conditions Few-nanometers-thick Fe3O4(111) filmswere epitaxially grown on Pt(111) and Ru(0001) single crystal supports
by sequential iron deposition and oxidation in an ultra-high vacuum chamber. The growth of well-ordered
magnetite films was confirmed by low energy electron diffraction. The films were covered with a protective
Au layer and subjected to magnetic and structural studies in ambient conditions. Magnetic hysteresis loops,
recorded using magneto-optical Kerr effect apparatus, confirmed magnetic ordering in both films at room temperature.
The Kerr measurements indicated in-plane orientation of magnetization, which was supported by the
lack of magnetic contrast in magnetic force microscopy images. Atomic force microscopy revealed significant
differences in morphology of the films, tentatively attributed to different lattice mismatch with Pt(111) and
Ru(0001) single crystal supports.
(C) 2015 Elsevier B.V. All rights reserved.
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Thin Solid Films, 591(B), 285-288, (2015) |
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9. |
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Mass spectrometry of lanthanide(III) complexes with 2,6-diformylpyridine bis(4-pyridylcarbohydrazone) and its unusual methylation observed in matrix-assisted laser desorption/ionization mass spectra Mass spectrometry of lanthanide(III) complexes with2,6-diformylpyridine bis(4-pyridylcarbohydrazone) and itsunusual methylation observed in matrix-assisted laserdesorption/ionization mass spectra.
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Rapid Communications in Mass Spectrometry, 29(18), 1696-1702, (2015) |
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10. |
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Synthesis of poly(OEOMA) using macromonomers via "grafting-through" ATRP Atom transfer radical polymerization (ATRP) of oligo(ethylene oxide) methyl ether methacrylate (OEOMA, M-n = 950 or 2080; OEOMA is also termed poly(ethylene glycol) methyl ether methacrylate, PEGMA) macromonomers was investigated as a function of initial monomer concentration, [OEOMA](0), ranging from 50 to 300 mM, and up to 4.5 kbar. Polymerizations were successfully carried out in organic solvents with [OEOMA](0) > 75 mM, whereas with [OEOMA](0) = 50 mM no monomer conversion was observed at ambient pressure, indicating that the macromonomer concentration was below its equilibrium monomer concentration ([M](e)). High pressure reduced [M](e) to a level lower than under ambient pressure, allowing polymerization at [OEOMA](0) = 50 mM up to high monomer conversion and yielding polymers with narrow molecular weight distribution. By varying the targeted degree of polymerization of OEOMA, brushlike or starlike poly(OEOMA) were prepared under both ambient and high pressure.
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Macromolecules, 48(18), 6385-6395, (2015) |
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11. |
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Study on structural, mechanical and optical properties of Al2O3-TiO2 nanolaminates prepared by atomic layer deposition Structural, optical, and mechanical properties of Al2O3/TiO2 nanolaminates fabricated by atomic layer deposition (ALD) were investigated. We performed transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray reflectivity (XRR), energy dispersive X-ray spectroscopy (EDX), ellipsometry, UV-vis spectroscopy, photoluminescence (PL) spectroscopy, and nanointendation to characterize the Al2O3/TiO2 nanolaminates. The main structural, optical, and mechanical parameters of Al2O3/TiO2 nanolaminates (thickness, grain size, refractive index, extinction coefficient, band gap, hardness, and Young’s module) were calculated. It was established that with decreasing of the layer thickness, the value of band gap energy increases due to the quantum size effect related to the reduction of the nanograins size. On the other hand, the decreasing of nanograins size leads to generation of interface defects and, as a consequence, to the increasing of Urbach energy. It was also shown that there is an interdiffusion layer at the Al2O3-TiO2 interface, which plays a crucial role in explaining mechanical and optical properties of Al2O3/TiO2 nanolaminates. The correlation between structural, optical, and mechanical parameters was discussed.
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Journal of Physical Chemistry C, 119(35), 20591-20599, (2015) |
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12. |
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Atomic layer deposition TiO2 coated porous silicon surface: Structural characterization and morphological features TiO2 thin films were grown on highly-doped p-Si (100) macro- and mesoporous structures by atomic layer deposition (ALD) using TiCl4 and deionized water as precursors at 300 °C. The crystalline structure, chemical composition, and morphology of the deposited films and initial silicon nanostructures were investigated by scanning electron microscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy and X-ray diffraction (XRD). The mean size of TiO2 crystallites was determined by TEM, XRD and Raman spectroscopy. It was shown that the mean crystallite size and the crystallinity of the TiO2 are influenced dramatically by the morphology of the porous silicon, with the mesoporous silicon resulting in a much finer grain size and amorphous structure than the macroporous silicon having a partially crystal anatase phase. A simple model of the ALD layer growth inside the pores was presented.
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Thin Solid Films , 589, 303-308, (2015) |
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13. |
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Structural and XPS studies of PSi/TiO2 nanocomposites prepared by ALD and Ag-assisted chemical etching PSi/TiO2 nanocomposites fabricated by atomic layer deposition (ALD) and metal-assisted chemical etching (MACE) were investigated. The morphology and phase structure of PSi/TiO2 nanocomposites were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM) with an energy dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. The mean size of TiO2 nanocrystals was determined by TEM and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical elemental composition by observing the behavior of the Ti 2p, 0 1s and Si 2p lines. TEM, Raman spectroscopy and XPS binding energy analysis confirmed the formation of TiO2 anatase phase inside the PSi matrix. The XPS valence band analysis was performed in order to investigate the modification of PSi/TiO2 nanocomposites electronic structure. Surface defects states of Ti3+ at PSi/TiO2 nanocomposites were identified by analyzing of XPS valence band spectra.
(C) 2015 Elsevier B.V. All rights reserved. |
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Applied Surface Science, 347, 777-783, (2015) |
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14. |
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Structural model of the bilitranslocase transmembrane domain supported by NMR and FRET data We present a 3D model of the four transmembrane (TM) helical regions of bilitranslocase (BTL), a structurally uncharacterized protein that transports organic anions across the cell membrane. The model was computed by considering helix-helix interactions as primary constraints, using Monte Carlo simulations. The interactions between the TM2 and TM3 segments have been confirmed by Forster resonance energy transfer (FRET) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy, increasing our confidence in the model. Several insights into the BTL transport mechanism were obtained by analyzing the model. For example, the observed cis-trans Leu-Pro peptide bond isomerization in the TM3 fragment may indicate a key conformational change during anion transport by BTL. Our structural model of BTL may facilitate further studies, including drug discovery.
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PloS ONE, 10(8), e0135455, (2015) |
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15. |
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Domain wall generated by graded interlayer coupling in Co/Pt/Co film with perpendicular anisotropy A magnetic multilayer of the structure substrate/Pt-15 nm/Co-0.8 nm/Pt-wedge(0-7 nm)/Co-0.6 nm/ Pt-2 nm is characterized by perpendicular anisotropy of both Co layers. For a Pt spacer thickness t(Pt) <= 2.6 nm, the magnetization reversal of the Co-layers occurs cooperatively, while for larger t(Pt), it occurs sequentially. The Co-layer with 0.6 nm thickness (Co-S) is magnetically softer than the second one (Co-H). In the 2.6 <= t(Pt) <= 3.0 nm range, there are significant changes of the switching field due to a strong gradient of the interlayer coupling. In this region, the magnetization reversal in the Co-S layer takes place reversibly by the propagation of a single, straight domain wall. This specific nature of magnetization reversal is explained by a decelerated motion of the domain wall observed both for the direction corresponding to the increasing, as well as decreasing coupling energy.
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Applied Physics Letters, 107(1), 012404, (2015) |
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16. |
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Porphyrazines with peripheral isophthaloxyalkylsulfanyl substituents and their optical properties Porphyrazines possessing isophthaloxyalkylsulfanyl substituents in the periphery were synthesized and subjected to various photophysical studies, including optical absorption and emission measurements. The fluorescence lifetimes of four porphyrazine derivatives were measured in different organic solvents. The results of the steady-state and time-resolved measurements of magnesium porphyrazines with different alkyl groups between sulfanyl substituent and isophthaloxy group were compared with those of demetallated porphyrazine. The porphyrazine macrocycles exhibit interesting solvatochromic effects, which are described by Delta f solvent polarity scale and four-parameter scale proposed by Catalan. Transient absorption spectroscopy was used to obtain the values of triplet lifetime for magnesium porphyrazine with 2-(3,5-dibutoxycarbonylphenoxy)ethylsulfanyl substituents. Values of singlet oxygen generation quantum yields were obtained in different organic solvents using various techniques, including the characteristic emission of the singlet oxygen at 1270 nm with the steady-state and time-resolved approaches.
(C) 2015 Elsevier B.V. All rights reserved. |
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Journal of Photochemistry and Photobiology A : Chemistry, 307-308, 54-67, (2015) |
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17. |
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Cambridge Structural Database, (2015) |
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18. |
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The influence of novel gemini surfactants containing cycloalkyl side-chains on the structural phases of DNA in solution Very important to gene therapy is the delivery system of the nucleic acids (called a vector), which will enhance the efficiency of the transport of new DNA into cells whilst protecting against damage. A promising alternative to the currently used viral vectors are the systems based on amphiphilic compounds - lipoplexes. Among them, gemini surfactants, which consist of two hydrophobic chains and two cationic heads connected by a linker spacer group, appear to be promising candidates. The subject of this study involves two gemini surfactants, alkoxy derivatives of bis-imidazolium quaternary salts, differing in the length of their spacer groups and how they interact with two types of salmon sperm DNA (low and high molecular weight (MW)) or plasmid DNA (pDNA). The mixtures of gemini surfactants with nucleic acids of differing p/n ratios (positive-to-negative charge ratio) were characterised by small angle X-ray scattering (SAXS) of synchrotron radiation, dynamic light scattering (DLS), circular dichroism (CD) spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and gel electrophoresis techniques. This analysis allows for the selection of the most suitable and promising candidates for non-viral vectors in gene therapy, determination of the conditions needed to form stable complexes, identification of conformational changes in the DNA molecules upon interactions with gemini surfactants and in some cases, determination of the structures formed in these lipoplexes.
(C) 2015 Elsevier B.V. All rights reserved. |
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Colloids and Surfaces B: Biointerfaces, 131, 83-92, (2015) |
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19. |
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Doxorubicin loaded PEG-b-poly(4-vinylbenzylphosphonate) coated magnetic iron oxide nanoparticles for targeted drug delivery Due to their unique physical properties, superparamagnetic iron oxide nanoparticles are increasingly used in medical applications. They are very useful carriers for delivering antitumor drugs in targeted cancer treatment. Magnetic nanoparticles with chemiotherapeutic were synthesized by coprecipitation method followed by coaling with biocompatible polymer. The aim of this work is to characterize physical and magnetic properties of synthesized nanoparicles. Characterization was carried out using EPR, HRTEM, X-ray diffraction, SQUID and NMR methods. The present findings show that synthesized nanosystem is promising tool for potential magnetic drug delivery.
(C) 2015 Elsevier B.V. All rights reserved |
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Journal of Magnetism and Magnetic Materials, 384, 320-327, (2015) |
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20. |
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Electrochemical properties of metallated porphyrazines possessing isophthaloxybutylsulfanyl substituents: Application in the electrocatalytic oxidation of hydrazine The demetallation reaction of sulfanyl magnesium(II) porphyrazine with isophthaloxybutyl substituents, accompanied by remetallation with zinc(II) and cobalt(II) salts, leads to the corresponding zinc(II) and cobalt(II) derivatives in moderate yields. All porphyrazines were analyzed by HPLC and characterized by UV-vis, MS and various NMR techniques (H-1-H-1 COSY, H-1-C-13 HSQC, H-1-C-13 HMBC). Voltammetric experiments conducted in dichloromethane solution showed that the novel porphyrazine complexes exhibit promising electrochemical properties. For all complexes one electron transfer process was observed in the studied potential range. Cobalt(II) porphyrazine revealed metal-involved redox couple at -0.79 V vs Fc/Fc(+), as well as peaks derived from ligand reduction/oxidation. Zinc(II) and demetalled porphyrazines showed well-defined macrocycle-based electron transfer processes. A glassy carbon electrode modified by carbon nanotubes/cobalt(II) porphyrazine - composite exhibited great electro-catalytic ability towards the oxidation of hydrazine. A combination of porphyrazine and carbon nanotubes makes it possible to obtain a synergistic effect that increased the rate of hydrazine oxidation. A significant decrease in the overpotential, compared to that obtained through glassy carbon electrode/cobalt( II) porphyrazine or glassy carbon electrode/carbon nanotubes, allows for sensitive determination of hydrazine in neutral conditions (pH 7.4). The novel cobalt(II) porphyrazine macrocycle seems to be a promising material for the design of novel amperometric sensors and electrocatalysts.
(C) 2015 Elsevier Ltd. All rights reserved. |
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Electrochimica Acta, 168, 216-224, (2015) |
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21. |
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Mesoporous drug carrier systems for enhanced delivery rate of poorly water-soluble drug: nimodipine Two mesoporous silica materials: MCM-41 and SBA-15 were applied as potential nanocarriers for poorly soluble drug—nimodipine. Drug incorporation was performed using modified adsorption from the solution method and loaded samples before and after washing procedure were studied. The physical properties were verified by: differential scanning calorimetry, X-ray powder diffraction, electron microscopies (SEM/TEM) and Fourier-transform infrared spectroscopy (FT-IR). FT-IR results for bulk nimodipine were interpreted on the basis of first principles calculations (DFT). As a result of encapsulation process, in both matrices nimodipine appeared simultaneously in two forms: crystalline and amorphous, but the first one turned out to be easily removable during washing procedure. The in vitro dissolution and release tests were performed with ultra pure water under supersaturating conditions. The release rate of the amorphous nimodipine from mesoporous silica materials was at least 70 times higher than dissolution rate of bulk drug, thus revealed a potential usefulness of such carrier in future pharmaceutical applications in terms of delivery of poorly soluble drugs.
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Journal of Porous Materials, 22(3), 817-829, (2015) |
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22. |
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PLoS ONE, 10(3), e0119969, (2015) |
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23. |
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Characterization of poly(ethylene 2,6-naphthalate)/polycarbonate blends by DSC, NMR off-resonance and DMTA methods The poly(ethylene 2,6-naphthalate) (PEN)/polycarbonate (PC) blends with the weight ratio of homopolymers 50/50 wt./wt. were prepared by injection molding using the Engel machine ES. One mixture was synthesized without the compatibilizer and the second with the compatibilizer SMAC (Samarium acetylacetonate hydrate). The influence of the cornpatibilizer on the physical and mechanical properties of the PEN/PC blends was investigated. The thermal properties of the new synthesized blends were studied by the differential scanning calorimetry (DSC). The molecular dynamics of the polymer blends was studied by the off-resonance NMR. The correlation times of the internal motions and the spectral density function amplitudes were estimated on the basis of the dispersion of the spin lattice relaxation time T1ρ(off) in the rotating frame off-resonance. The rheological properties of the studied blends were investigated by dynamic mechanical thermal analysis (DMTA). The temperature dependencies of the storage modulus G', of the loss modulus G" and of the loss tangent (tan δ) were analyzed in order to evaluate the relaxation processes in the studied systems. The analysis of the DMTA data revealed the existence of two primary (α(1) and α(2)) and two secondary (β and γ) relaxation processes in the blend of PEN/PC 50/50 wt./wt. and one primary (α) and two secondary (β and γ) relaxation processes in the blend of PEN/PC 50/50 wt./wt with the compatibilizer. The motional parameters for the above - mentioned relaxation processes were calculated using the Havriliak Negami formalism. The comparative analysis of the DSC, NMR off-resonance and DMTA results led to the clarification of the molecular motion in the PEN/PC 50/50 wt./wt. blends.
(C) 2015 Elsevier Ltd. All rights reserved. |
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European Polymer Journal, 64, 62-69, (2015) |
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24. |
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Cytotoxicity of thermo-responsive polymeric nanoparticles based on N-isopropylacrylamide for potential application as a bioscaffold Polymeric nanoparticles based on poly-N-isopropylacrylamide (pNiPAM NPs) and their bio-medical applications have been widely investigated in recent years. These tunable nanoparticles are considered to be great candidates for drug delivery systems, biosensors and bioanalytical devices. Thus, the biocompatibility and toxicity of these nanoparticles is clearly a crucial issue. In this work, the cytotoxicity of thermo-responsive pNiPAM nanoparticles was studied, followed by a detailed analysis of the NPs morphology in growing cell cultures and their 3D structure. Cytotoxic examination was conducted for two cell cultures - HeLa (cervical cancer cell line) and HeK293 (human embryonic kidney cell line), employing MTT (3-4, 5-dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide) assay and viability tests. We used Cryo-SEM (scanning electron microscopy) and fluorescence microscopy (IN Cell Analyzer) in order to investigate the morphological structure of the polymer network. We show that pNiPAM nanoparticles do not exhibit any cytotoxicity effects on the investigated cell lines. Additionally, we report that the pNiPAM nanoparticle based scaffold promotes cell growth.
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Acta Biochimica Polonica, 62(2), 311-316, (2015) |
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25. |
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Studies of zwitterionic lipoplexes - nanosystem based on phospholipids and surfactants as innovative delivery systems for gene therapy The gene therapy is the one of the most promising method of treatment in contemporary medicine. This way of therapy is very useful in the treatment a dozen of incurable or fatal diseases. This method of treatment is leaned on implement a gene into patient's cells with the use of dedicated delivery systems (vectors). The main problem of gene therapy is to find the best vector which will be effective and will be not toxic for human cells. A good approach seems to be use of non-viral vectors like delivery system based on lipid-surfactant mixtures.
The aim of this study was to examine the possible application of selected amphoteric surfactants (zwitterionic alkyl derivatives of sulfobetaine) as complexing agents (with and without helper lipid) for nucleic acids (siRNA, low and high-molecular weight DNA). The studies of DNA conformation in selected DNA - zwitterionic surfactant lipoplexes were performed using the circular dichroism (CD) spectroscopy. CD spectra were recorded in the spectral range 350 - 200 nm by using J-815 spectrometer (Jasco). The results obtained indicate that the DNA maintains the B-form for wide range of surfactant concentrations in the solution. The structure and organization of lipoplexes was also independently analyzed by the Fourier transform infrared spectroscopy. The absorption spectra for lipoplexes were collected by using FTIR spectrometer BRUKER Tensor 27 in the temperature range 2-40°C. The phase transitions in examined systems were studied by using the differential scanning calorimetry (DSC). Ability of creating of stable complexes in DNA-surfactant systems studied was confirmed using electrophoresis on agarose gel. For all formed stable lipoplexes the complete reduction of electrophoretic mobility was observed. Finally the transfection efficiency of selected systems were also tested on HeLa cells. |
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Biophysical Journal, 108(2) S1, 545A, (2015) |
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26. |
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Spectroscopic and SAXS studies of human cystatin c mutants - early stages of amyloid formation process Human cystatin C (HCC) is a cysteine protease inhibitor. This protein in pathological conditions, forms dimers via a “domain swapping” mechanism. HCC is also associated with two types of amyloid deposition diseases - hereditary amyloid angiopathy (related to the Leu68Gln mutation) and wild-type cystatin C co-precipitation.
The aim of our studies was the characterisation of the self-assembling properties of native and mutated (at positions 57 or 68) forms of human cystatin C in solution. The structure, overall conformation and secondary structure changes in solution were studied by Fourier transformed infrared spectroscopy (FTIR), circular dichroism spectroscopy (CD), dynamic light scattering (DLS) and time resolved small angle scattering of synchrotron radiation (TR-SAXS). SAXS data for native and mutated HCC were subjected to analysis by using SVD and MCR-ALS methods as well as the low resolution structure determination. Besides the monomeric forms of human cystatin C, also dimers and higher oligomers were formed even after short (50-ms) exposure on synchrotron radiation. In addition we observed for first time, formation of domain swapped dimers of human cystatin C induced by irradiation. The spectroscopic studies confirmed conformational changes. Authors acknowledge also the partial support by HARMONIA3 grant (Project No. 2012/06/M/ST4/00036) from National Science Centre (Poland). |
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Biophysical Journal, 108(2) S1, 516A, (2015) |
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27. |
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The study of complexation process between cationic gemini surfactants and dna using structural and spectroscopic methods Dicationic (gemini) surfactants are intensively studied group of chemical compounds, because of the broad range of applications in medicine, chemical technology or pharmaceutical industry. In solution they can form with nucleic acids the complex structures (lipoplexes), which can be used as drug delivery systems in nonviral transfection. Lipoplexes in gene therapy offer efficient introduction of a therapeutic material to the living cells. Gemini surfactants also allow introduction of a transgene without inducing natural immunological response and release it inside the cell. In our study, we analyzed the process of complexation of cationic gemini surfactants (3.3'- [1,6- (2,n-dioxyalcane)] bis(1-dodecyloxyimidazolium dichlorides)) with DNA, using small angle X-ray scattering, circular dichroism spectroscopy and gel electrophoresis. Surfactants which have been used had of variable length of the spacer group. We observed the formation of stable complexes in these systems and the process of complex formation was reproducible, efficient and immediate.
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Biophysical Journal, 108(2) S1, 392A, (2015) |
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28. |
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Nanosystem based on phospholipids and surfactants as innovative delivery system for gene therapy Amphiphilic dicationic surfactants, known as gemini surfactants, are currently studied for gene delivery purposes. The biggest advantages of these systems are that they are non-immunogenic and generally have low toxicity. One of the most important advantages of these systems is improved transfection efficiency. The aim of this study was to determine the possibility to use amphoteric surfactants (zwitterionic derivatives of sulfobetaine with carbohydrate moiety) and sulfobetaine/gemini surfactant mixtures as complexing agents for nucleic acids, with potential applications for gene delivery to reduce the toxicity and improved transfection. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) were used to a7nalyze influence of surfactants on the phase behaviour of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) bilayers with the presence of different DNA forms (small DNA oligomers, cDNA, low and high-molecular mass DNA). The influence of different concentrations of sulfobetaine and sulfobetaine/gemini surfactant mixtures with the presence of DNA on creating stable complexes was investigated using circular dichroism (CD) spectroscopy and electrophoresis. A series of measurements of toxicity and transfection of these lipoplexes were performed in HeLa cells. These compounds appear to be excellent for creating complexes with DNA. Thanks to their construction this DNA carrier molecules might be able to deliver genes to the cells of almost any DNA mo7lecular size, unattainable when using viral gene delivery systems.
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Biophysical Journal, 108(2) S1, 245A, (2015) |
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29. |
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RNA and DNA diagnostics preface The aim of molecular diagnostics is preferentially to detect a developing disease before any symptoms appear. There has been a significant increase, fueled by technologies from the human genome project, in the availability of nucleic acid sequence information for all living organisms including bacteria and viruses. When combined with a different type of instrumentation applied, the resulting diagnostics is specific and sensitive. Nucleic acid-based medical diagnosis detects specific DNAs or RNAs from the infecting organism or virus and a specific gene or the expression of a gene associated with a disease. Nucleic acid approaches also stimulate a basic science by opening lines of inquiry that will lead to greater understanding of the molecules at the center of life. One can follow Richard Feynman’s famous statement “What I cannot create, I do not understand.”
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Book Series: RNA Technologies, Erdmann V.A., Jurga S., Barciszewski J. (Eds.), V-VII, Springer-Verlag Berlin, Heidelberger Platz 3, d-14197 Berlin, Germany, (2015) |
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30. |
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Tuning the photodynamic efficiency of TiO2 nanotubes against HeLa cancer cells by Fe-doping In this study Fe-doped TiO2 (0.35 to 3.50 wt% Fe) nanotubes (NTs) were prepared as the potential photosensitizer for near-visible light driven photodynamic therapy (PDT) against cervical cancer cells (HeLa). Characterization of the prepared nanotubes by X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the successful incorporation of Fe3+ as a dopant into the TiO2 matrix, which was mainly composed of an anatase phase, while elemental mapping using energy dispersive X-ray spectroscopy (EDX) showed homogenous distribution of the dopant ions in TiO2 for both low and high doping levels. UV-Vis studies showed that Fe doping in TiO2 increases the light absorption within the visible range, particularly in the case of 0.70 and 1.40 wt% Fe-TiO2 and provides additional energy levels within the band gap, which promotes the photo-excited charge transport towards the conduction band. Photo-cytotoxic activity of the prepared Fe-doped TiO2 NTs was investigated in vitro against cervical cancer cells (HeLa) and compared with human normal fibroblasts (GM07492). Fe-doped TiO2 NTs exhibited no or lower dark cytotoxicity than un-doped TiO2 NTs, which confirms their superior biocompatibility. Under the near-visible light irradiation (similar to 405 nm) Fe-doped TiO2 NTs showed higher photo-cytotoxic efficiency than un-doped TiO2 NTs, which was found to be dependent on the NTs concentration, but not on the incubation time of cells after near-visible light irradiation. The highest activity was observed for 0.70 and 1.40 wt% Fe-TiO2 NTs. Fluorescent labeling of treated HeLa cells showed distinct morphological changes, particularly in the perimitochondrial area suggesting a mitochondria-involved apoptosis of cells, but also the nuclei and cytoskeleton were subject to Fe-TiO2 NTs induced photo-damage. Apoptosis of PDT treated HeLa cells was also confirmed using ethidium homodimer (EthD-1).
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RSC Advances, 5(103), 85139-85152, (2015) |
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31. |
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Novel nanostructured hematite-spongin composite developed using an extreme biomimetic approach The marine sponge Hippospongia communis (Demospongiae: Porifera) is a representative of bath sponges, which possess characteristic mineral-free fibrous skeletons made of a structural protein - spongin. This fibrous skeleton is mechanically robust, resistant to acidic treatment, and thermally stable up to 160 degrees C. Due to these properties, we decided to use this biological material for the first time for the hydrothermal synthesis of hematite (alpha-Fe2O3) via catalyzed hydrolysis of FeCl3 to obtain a hematite-spongin composite. The material obtained was studied with Scanning Electron Microscopy (SEM), High-Resolution Transmission Electron Microscopy (HR-TEM), X-ray Photoemission Spectroscopy (XPS) and Raman spectroscopy. The alpha-Fe2O3-spongin-based composite was tested for its potential application as an anode material in a capacitor. The results indicate that components constructed using this novel composite material have a positive effect on the capacitance of energy storing devices.
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RSC Advances, 5(96), 79031-79040, (2015) |
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32. |
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Synthesis and NMR and mass spectrometric study of ammonioacetohydrazones of formylphenylboronic acids as novel ionic prospective sugar receptors Novel sugar-sensing, soluble in aqueous media, boronic acid derivatives designed for easy analysis through MALDI mass spectrometry have been synthesized in a high yield through a mild and efficient procedure. The synthesized compounds are based on formylphenylboronic acids, which can bind through the formyl group with acid hydrazides to form the respective hydrazones. As hydrazide substrates, Girard reagents T and P were chosen, which possess precharged ammonium and pyridinium moieties, respectively. Nuclear magnetic resonance spectroscopy (H-1, C-13, HSQC, HMBC, and NOESY) and mass spectrometry were employed to study their structure, conformational equilibrium and interaction with selected sugars and other diols. Our study shows that the ammonioacetohydrazones of formylphenylboronic acids are present in DMSO solution in the form of cis/trans amide conformers and the effectiveness of their interaction with sugars depends on the situation of the substituent in relation to the boronic acid group. Introducing an ionic group to the receptor molecule improves the sensitivity for conjugate detection when analyzed by MS with matrix-assisted laser desorption/ionization (MALDI) in the positive-ion mode.
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New Journal of Chemistry, 39(6), 4695-4707, (2015) |
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