Attila Bóta - Academia.edu (original) (raw)

Papers by Attila Bóta

The evolution of equilibrium poly(styrene sulfonate) and dodecyl trimethylammonium bromide supramolecular structure in dilute aqueous solution with increasing surfactant binding

Journal of Colloid and Interface Science, Dec 1, 2023

Colloids and Surfaces B: Biointerfaces, Aug 1, 2020

Size characterization of extracellular vesicles (EVs) and drug delivery liposomes is of great imp... more Size characterization of extracellular vesicles (EVs) and drug delivery liposomes is of great importance in their applications in diagnosis and therapy of diseases. There are many different size characterization techniques used in the field, which often report different size values. Besides technological biases, these differences originate from the fact that various methods measure different physical quantities to determine particle size. In this study, the size of synthetic liposomes with nominal diameters of 50nm and 100nm, and red blood cell-derived EVs (REVs) were measured with established optical methods, such as dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA), and with emerging non-optical methods such as microfluidic resistive pulse sensing (MRPS) and very small-angle neutron scattering (VSANS). The comparison of the hydrodynamic sizes obtained by DLS and NTA with the sizes corresponding to the excluded volume of the particles by MRPS enabled the estimation of the thickness of the hydration shell of the particles. The comparison of diameter values corresponding to the boundary of the phospholipid bilayer obtained from VSANS measurements with MRPS size values revealed the thickness of the polyethylene glycol-layer in case of synthetic liposomes, and the thickness of the protein corona in case of REVs.

$Research paper thumbnail of Development of powder diffraction apparatus for small-angle X-ray scattering measurements$

Journal of Applied Crystallography, Feb 23, 2013

Journal of Applied Crystallography covers a wide range of crystallographic topics from the viewpo... more Journal of Applied Crystallography covers a wide range of crystallographic topics from the viewpoints of both techniques and theory. The journal presents papers on the application of crystallographic techniques and on the related apparatus and computer software. For many years, the Journal of Applied Crystallography has been the main vehicle for the publication of small-angle scattering papers and powder diffraction techniques. The journal is the primary place where crystallographic computer program information is published. Crystallography Journals Online is available from journals.iucr.org

SAXS study on activated carbons

Structure and sorption dynamics of activated carbons from wooden precursors: Further possibilities to reveal anisotropic behaviors in the carbon skeleton

Nova Science Publishers, Inc. eBooks, 2013

The anisotropic structure of activated carbons prepared from the trunks of different woods (Norwe... more The anisotropic structure of activated carbons prepared from the trunks of different woods (Norwegian spruce, European beech, Pedunculate oak) was studied by small-angle X-ray scattering recorded by a two-dimensional detector. It was found that the type of the precursor has strong influence onto the structure of the end-product for low conversion rates. Higher (cca. 50 %) burn-off results in similar features of the micropore system. The decrease of the inherent anisotropy of the precursors during activation was also observed. Specific surface and pore size distribution were characterized by the well-established methods of static adsorption measurements (N2 adsorption, iodine number, methylene-blue adsorption). A novel, dynamic technique, such as frequency-response (FR) has also been applied taken advantage of its unique potentials. The obtained three-dimensional carbonized frames exhibit very low transport diffusional resistance due to the wide one-dimensional straight transport channels of micron size in tangential direction. The evolution of propane mass transport dynamics in the three series of the activated carbon preparations provides evidence for the complex diffusion processes in the pore system of the carbonized cell walls and for the significant differences in the mass transport dynamic occuring in micropores and the lowest range of mesopores depending on evolution of pore structure determined by the history of the activation.

Combination of multifunctional ursolic acid with kinase inhibitors for anti-cancer drug carrier vesicles

Materials Science and Engineering: C, Dec 1, 2021

A sterically stabilized unilamellar nanocarrier vesicle (SSV) system containing dipalmitoylphosph... more A sterically stabilized unilamellar nanocarrier vesicle (SSV) system containing dipalmitoylphosphatidylcholine, cholesterol, ursolic acid and PEGylated phospholipid has been developed by exploiting the structural advantages of ursolic acid: by spontaneously attaching to the lipid head groups, it induces curvature at the outer side of the bilayers, allowing the preparation of size-limited vesicles without extrusion. Ursolic acid (UA) also interacts with the PEG chains, supporting steric stabilization even when the amount of PEGylated phospholipid is reduced. Using fluorescence immunohistochemistry, vesicles containing ursolic acid (UA-SSVs) were found to accumulate in the tumor in 3 h on xenografted mouse, suggesting the potential use of these vesicles for passive tumor targeting. Further on, mono- and combination therapy with UA and six different kinase inhibitors (crizotinib, erlotinib, foretinib, gefitinib, refametinib, trametinib) was tested on seven cancer cell-lines. In most combinations synergism was observed, in the case of trametinib even at very low concentration (0.001 μM), which targets the MAPK pathway most often activated in human cancers. The coupled intercalation of UA and trametinib (2:1 molar ratio) into vesicles causes further structural advantageous molecular interactions, promoting the formation of small vesicles. The high drug:lipid molar ratio (~0.5) in the novel type of co-delivery vesicles enables their direct medical application, possibly also overcoming the multidrug resistance effect.

Colloids and Surfaces B: Biointerfaces, Mar 1, 2006

The vesicle system consisting of 80 mol% dipalmitoylphosphatidylethanolamine (DPPE) and 20 mol% d... more The vesicle system consisting of 80 mol% dipalmitoylphosphatidylethanolamine (DPPE) and 20 mol% dipalmitoylphosphatidylglycerol (DPPG) undergoes to structural changes caused by various concentrations of Salmonella minnesota R595 lipopolysaccharide (LPS). The phenomenon was investigated by methods applying small-and wide-angle X-ray scattering (SAXS and WAXS), calorimetry (DSC) and freeze-fracture. In the low LPS concentration regime (investigated at 0.02 LPS/DPPE-DPPG molar ratio) a phase separation was observed. Two kind of domains are formed which are rich and poor in DPPE and in these domains cubic and lamellar structures are present, respectively. Increasing the LPS concentration up to 0.1 LPS/DPPE-DPPG molar ratio the phase separation is more expressed and the temperature domains of the phase transitions are more different. Increasing the temperature chain melting of the lamellar phase occurs first and destruction of the cubic phase is observed later. At high LPS concentration (equimolar ratio of LPS/DPPE-DPPG), where this amphiphilic molecule cannot be considered any more a guest molecule, the cubic structure dominates the phase behaviour of the LPS molecules.

Journal of Applied Crystallography, Apr 21, 2007

The formation of copper hydroxide and copper oxide particles in the gaps among the stacks of mult... more The formation of copper hydroxide and copper oxide particles in the gaps among the stacks of multilamellar vesicles is described, illustrating a new pathway in the preparation of nanometre-scale particles. The in situ structural characterization of both the solid particles and the vesicles as a reaction medium was performed in the initial and final states of the process by using anomalous small-angle X-ray scattering (ASAXS) and freeze-fracture methods. The ASAXS method provides a description of the particle-size distribution of the copper nanoparticles, in spite of the fact that they are present in low concentration. This method allows the particle formation and growth to be monitored throughout the whole time range of the synthesis. conference papers J. Appl. Cryst. (2007). 40, s259-s263 Attila Bó ta et al. Vesicles as reactors of nanoparticles s263

Thermodynamic and structural study of DMPC–alkanol systems

Physical Chemistry Chemical Physics, 2021

A fluid-fluid immiscibility of the DMPC-C12OH system above threshold concentration with a consequ... more A fluid-fluid immiscibility of the DMPC-C12OH system above threshold concentration with a consequent formation of domains with different C12OH contents is suggested.

Evaluation of small-angle x-ray scattering data of a Raney-type Ni catalyst with computer simulation

Journal of Chemical Physics, Nov 15, 2004

A reverse Monte Carlo-type simulation method was developed for the evaluation of anomalous small-... more A reverse Monte Carlo-type simulation method was developed for the evaluation of anomalous small-angle x-ray scattering data of a Raney-type Ni catalyst. Based on other experimental data the catalytic Ni particles were modeled as small crystalline cylinders dispersed in the matrix. The average size of the Ni particles and their pair-correlation function were determined. Despite the unknown density of the catalyst, it is shown that each particle has about 2 neighbors in the first neighboring shell independent of the modeling density, and the position of the first peak of the pair-correlation function does not depend on the modeling density. A method was elaborated to get reasonable performance of the Reverse Monte Carlo-type simulation. The scattered intensity was calculated on the basis of probe scattering atoms put inside the cylinders. The effects of the omission of the real number of the atoms, the unknown density, the lack of normalization and the uncertainties in the cross sections were unified in two constants that were determined during the simulation. The method can be used for nanoparticles with other shape, where analytic form factors are complicated, and it may be powerful in the investigation of the usually neglected or simplified inter-particle structure of these systems.

Frequency-Response Evidence for Parallel Diffusion Processes in the Bimodal Micropore System of an Activated Carbon

Helvetica Chimica Acta, Aug 1, 2002

ABSTRACT

Journal of The Mechanical Behavior of Biomedical Materials, Feb 1, 2020

The release of neutrophil extracellular traps (NETs) containing DNA and histones is an essential ... more The release of neutrophil extracellular traps (NETs) containing DNA and histones is an essential mechanism in the neutrophil-mediated innate immunity. In thrombi the polyanionic DNA confers mechanical and lytic resistance to fibrin and heparins interfere with the effects of NET components. Heparins are polyanions used not only as therapeutic agents, but they are also released by mast cells at entry sites of pathogens. Platelets and microorganisms release a different type of polyanions (polyphosphates) of various size (in the range 60-1000 phosphate monomers). With the current study we aimed to evaluate if the stability of fibrin is influenced by the type of polyanion, its molecular size or relative electric charge. Fibrin structure was approached with scanning electron microscopy (SEM) and pressure-driven permeation. An oscillation rheometer was used to investigate viscoelastic properties. Kinetic turbidimetric assays for the generation and dissolution of composite fibrin clots containing unfractionated heparin (UFH), and its partially or fully desulfated derivatives, as well as low molecular-weight heparin (LMWH), pentasaccharide (S5), and polyphosphates composed of 45 (P45), 100 (P100) or 700 (P700) monomers at average. The smaller polyanions P45, P100, LMWH, and S5 accelerated, whereas P700 and UFH retarded clot formation. All polyanions altered the fibrin structure: SEM and clot permeation showed thicker fibers with smaller (LMWH, S5, P700) or larger (UFH, P100) pores. All polyanions stabilized the clots mechanically, but the smaller P45, P100 and LMWH decreased the deformability of fibrin, whereas the large UFH and P700 increased the maximal bearable deformation of clots. Despite the size-dependent structural changes, all heparins caused a 10-15% prolongation of lysis-times with plasmin, and UFH-effects depended on sulfation patterns. The 20-35% prolongation of lysis-times caused by all polyphosphates was a kringle-dependent phenomenon, and was dampened in the presence of 6-aminohexanoate blocking the lysinebinding sites of plasmin. In summary, we found that polyanions of different chemical structure stabilize fibrin clots via size-dependent modulation of fibrin structure and kringle-dependent inhibition of plasminmediated fibrinolysis. Supplementary Material Biorelevant polyanions stabilize fibrin against mechanical and proteolytic decomposition: effects of polymer size and electric charge

Sorption dynamics of N2 and O2 in carbon monoliths from spruce, beech and oak affected by activation

Microporous and Mesoporous Materials, Apr 1, 2009

Three series of activated carbon monoliths have been prepared from logs of different trees (spruc... more Three series of activated carbon monoliths have been prepared from logs of different trees (spruce (Picea abies), beech (Fagus silvatica), oak (Quercus robur)) by pyrolization in nitrogen flow at 700°C and then by steam activation at 900°C for different duration of the conversion. The characterization of carbon skeleton in the samples was performed by small angle X-ray scattering (SAXS), atomic

Colloids and Surfaces A: Physicochemical and Engineering Aspects, Jun 1, 1998

Carbonaceous composite materials were produced from various pyrolyzed organic waste materials by ... more Carbonaceous composite materials were produced from various pyrolyzed organic waste materials by steam activation. Fractal dimensions derived from SAXS and adsorption measurements were used to explain the changes in the matrix and the surface microstructure, due to the activation. The comparison of the fractal dimensions from SAXS and nitrogen adsorption data can be successfully applied to understand the development of the porous structure. In these materials, of heterogeneous matrix, no correlation was found between the B.E.T. specific surface area and the fractal dimensions derived from various methods. The adsorption of different substrates is disturbed by the chemical heterogeneity of the surface. In these cases, the applicability of aqueous solutions in the description of the surface geometry might be questioned.

Biophysical Chemistry, Feb 1, 2007

The effect of the frequently used antibiotic sulfadiazine (SD) was studied on a bacteria membrane... more The effect of the frequently used antibiotic sulfadiazine (SD) was studied on a bacteria membrane mimetic model system by using differential scanning calorimetric (DSC), small-and wide-angle X-ray scattering (SWAXS) and freeze-fracture methods. The membrane model system consisted of dipalmitoylphosphatidylethanolamine (DPPE, 0.8 molar ratio) and dipalmitoylphosphatidylglycerol (DPPG, 0.2 molar ratio). The SD molar ratio (relative to the lipids) was varied between 10 − 3 and 1. In the presence of SD, two transitions between the gel and liquid crystalline phases appear at 60.5°C and about at 65°C. In the temperature domain of the gel phase, the subcell of the chain packing is strongly temperature dependent indicating the increased dominance of the hydration forces during the first transition and the location of SD molecules in the neighbourhood of the polar lipid head groups. The second transition is accompanied by the changes in the nanometer-scale layer arrangements observed by SAXS and in the μm-scale morphology observed by freeze-fracture. Above the temperature of the second transition, the SD-induced metastable structures undergo further formations to produce a more homogeneous state favoured by the geometrical packing of the cylindricalshaped lipid molecules.

Colloids and Surfaces A: Physicochemical and Engineering Aspects, Nov 1, 1998

Transitional states in multilamellar fully hydrated dipalmitoylphosphatidylcholine (DPPC) liposom... more Transitional states in multilamellar fully hydrated dipalmitoylphosphatidylcholine (DPPC) liposomes were studied by using small and wide angle X-ray scattering. The incubation technique was applied to achieve conditions as close as possible to equilibrium. The structures formed in the wide temperature range (30-37°C) of the pretransition are very different depending on the starting temperatures, 28 and 38°C, respectively. The difference weakens with time but does not completely vanish even after one week of incubation. The parent phases, the gel (L b∞) and the rippled gel (P b∞) are present in the whole temperature range. The amounts of the phases do not change during the pretransition simultaneously. When the samples are cooled down from the narrower transitional temperature range, a previously existing L b∞ with destroyed layer structure is reformed. However, when heated from this stage up to above the transitional temperature into the phase P b∞ , a more disordered layer structure is formed. This complex thermal prehistory can be interpreted by a memory effect with respect to the one-dimensional lattice structure. The present work has revealed that the structures formed in the critical transition temperature domain produce extreme variety and this feature may have importance in the regulation of membrane transport properties.

British Journal of Radiology, Nov 1, 2020

Ionising radiation-induced alterations affecting intercellular communication in the bone marrow (... more Ionising radiation-induced alterations affecting intercellular communication in the bone marrow (BM) contribute to the development of haematological pathologies. Extracellular vesicles (EVs), which are membrane-coated particles released by cells, have important roles in intercellular signalling in the BM. Our objective was to investigate the effects of ionising radiation on the phenotype of BM-derived EVs of total-body irradiated mice. Methods: CBA mice were irradiated with 0.1 Gy or 3 Gy X-rays. BM was isolated from the femur and tibia 24 h after irradiation. EVs were isolated from the BM supernatant. The phenotype of BM cells and EVs was analysed by flow cytometry. Results: The mean size of BM-derived EVs was below 300 nm and was not altered by ionising radiation. Their phenotype was very heterogeneous with EVs carrying either CD29 or CD44 integrins representing the major fraction. High-dose ionising radiation induced a strong rearrangement in the pool of BM-derived EVs which were markedly different from BM cell pool changes. The proportion of CD29 and CD44 integrin-harbouring EVs significantly decreased and the relative proportion of EVs with haematopoietic stem cell or lymphoid progenitor markers increased. Low-dose irradiation had limited effect on EV secretion. Conclusions: Ionising radiation induced selective changes in the secretion of EVs by the different BM cell subpopulations. Advances in knowledge: The novelty of the paper consists of performing a detailed phenotyping of BM-derived EVs after in vivo irradiation of mice.

Distortion of the lamellar arrangement of phospholipids by deep rough mutant lipopolysaccharide from Salmonella minnesota

Journal of Thermal Analysis and Calorimetry, Nov 1, 2005

The concentration dependent effects of deep rough mutant lipopolysaccharide (LPS) from Salmonella... more The concentration dependent effects of deep rough mutant lipopolysaccharide (LPS) from Salmonella minnesota (R595) on two different phospholipid model membranes was investigated by differential scanning calorimetry and small-angle X-ray scattering (SAXS). At low concentrations of LPS the well ordered multilamellar arrangement of dipalmitoylphosphatidylcholine (DPPC) vesicles is strongly distorted resulting in a loss of positional correlation of the lipid lamellae and

European Polymer Journal, Sep 1, 2013

Introduction 202 Experimental Sample Preparation Birefringence Measurements Density Measurements ... more Introduction 202 Experimental Sample Preparation Birefringence Measurements Density Measurements Differential Scanning Calorimetry Measurements 207 Shrinkage Measurements 209 Results 209 Correlation of Orientation and Crystallinity of the Samples with Melt Deformation 209 Correlation of the Measured Properties of the Samples with Melt Temperature a) Shrinkage and birefringence b) Density 215 c) Differential scanning calorimetry Conclusions Acknowledgements References

SZABÓ Ákosa, MEZEY Pétera,b, FODOR Csabaa, DOMJÁN Attilac, KALI Gergelya,d, STUMPHAUSER Tímeaa, E... more SZABÓ Ákosa, MEZEY Pétera,b, FODOR Csabaa, DOMJÁN Attilac, KALI Gergelya,d, STUMPHAUSER Tímeaa, ERDŐDI Gábora,e, Ralf THOMANNf, NÉMETH Péterg, SZANKA Istvána, ILLÉS Gergelya,h, HARASZTI Mártona,i, PÁSZTOR Szabolcsa, BÓTA Attilaj, WACHA Andrásj, SÜVEGH Károlyk és IVÁN Bélaa,* aMTA TTK AKI Polimer Kémiai Kutatócsoport, Magyar tudósok körútja 2., H-1117 Budapest, Magyarország bjelenleg: BorsodChem Zrt., Pattantyús Ábrahám körút 12., H-2100 Gödöllő, Magyarország cMTA TTK SZKI NMR Kutatócsoport, Magyar tudósok körútja 2., H-1117 Budapest,Magyarország djelenleg: Universität des Saarlandes, Campus C 4.2, D-66123 Saarbrücken, Németország eThe Lubrizol Corporation, Brecksville Road 9911, OH-44141 Cleveland, Amerikai Egyesült Államok fAlbert-Ludvigs-Universität Freiburg, Freiburger Materialforschungszentrum, Stefan-Meier-Str. 21., D-79104 Freiburg, Németország gMTA TTK AKI Plazmakémiai Kutatócsoport, Magyar tudósok körútja 2., H-1117 Budapest, Magyarország hjelenleg: Egis Gyógyszergyár Zrt., ...