TY - JOUR T1 - A biocompatible hybrid material with simultaneous calcium and strontium release capability for bone tissue repair JF - Materials Science and Engineering: C Y1 - 2016 A1 - Almeida, J. Carlos A1 - András Wacha A1 - Gomes, Pedro S. A1 - Alves, Luís C. A1 - Fernandes, M. Helena Vaz A1 - Salvado, Isabel M. Miranda A1 - Fernandes, M. Helena R. KW - Biocompatible KW - Hybrid materials KW - peer-reviewed KW - Strontium AB -

The increasing interest in the effect of strontium in bone tissue repair has promoted the development of bioactive materials with strontium release capability. According to literature, hybrid materials based on the system PDMS–{}SiO2 have been considered a plausible alternative as they present a mechanical behavior similar to the one of the human bone. The main purpose of this study was to obtain a biocompatible hybrid material with simultaneous calcium and strontium release capability. A hybrid material, in the system PDMS–{}SiO2–{}CaO–{}SrO, was prepared with the incorporation of 0.05 mol of titanium per mol of SiO2. Calcium and strontium were added using the respective acetates as sources, following a sol–{}gel technique previously developed by the present authors. The obtained samples were characterized by FT-IR, solid-state NMR, and SAXS, and surface roughness was analyzed by 3D optical profilometry. In vitro studies were performed by immersion of the samples in Kokubo's SBF for different periods of time, in order to determine the bioactive potential of these hybrids. Surfaces of the immersed samples were observed by SEM, EDS and PIXE, showing the formation of calcium phosphate precipitates. Supernatants were analyzed by ICP, revealing the capability of the material to simultaneously fix phosphorus ions and to release calcium and strontium, in a concentration range within the values reported as suitable for the induction of the bone tissue repair. The material demonstrated to be cytocompatible when tested with MG63 osteoblastic cells, exhibiting an inductive effect on cell proliferation and alkaline phosphatase activity.

VL - 62 ER - TY - THES T1 - Nanostructure Research by Small-Angle X-Ray Scattering: From Instrument Design to New Insights in Materials Sciences T2 - Physics Y1 - 2016 A1 - András Wacha AB -

My thesis work presents the versatility of the small-angle X-ray scattering (SAXS) method in the structural research of nanomaterials. It contains the details of the design and construction of a new, highly effective laboratory SAXS instrument. The uniqueness of this apparatus—{}even by international standards—{}lies in the extremely broad small- and wide-angle range, and its high signal-to-noise ratio. This is ensured by the special optimization method developed for the beam shaping system. The performance of the instrument is further enhanced by the custom-made instrument control software and data analysis framework, the flexibility and accuracy of which is outstanding even among synchrotron SAXS beamlines. Due to these special methods, material systems which are too weak scatterers for traditional laboratory cameras became measurable on this apparatus. I have validated the instrument by accurately determining the size distribution of spherical SiO2 nanoparticles. Other new scientific results obtained using this instrument are presented on case studies of size and shape determination of protein solutions, and in situ characterization of a self-assembling gold-cysteine photoluminescent nanocomplex. Additionally, results on the anisotropy in wood-derived activated carbons are also presented, showcasing the possibilities of SAXS on complex hierarchical systems, as well as the algorithms developed for the instrument and SAXS data interpretation in general.

JF - Physics PB - Budapest University of Technology and Economics CY - Budapest VL - PhD UR - https://repozitorium.omikk.bme.hu/bitstream/handle/10890/1524/ertekezes.pdf?sequence=2&isAllowed=y ER - TY - JOUR T1 - Amfifil polimer kotérhálók: egy újszerű nanoszerkezetű anyagcsoport JF - Magyar Kémiai Folyóirat - Kémiai Közlemények Y1 - 2015 A1 - Szabó, Ákos A1 - Mezey, Péter A1 - Fodor, Csaba A1 - Domján, Attila A1 - Kali, Gergely A1 - Stumphauser, Tímea A1 - Erdődi, Gábor A1 - Thomann, Ralf A1 - Németh, Péter A1 - Szanka, István A1 - Illés, Gergely A1 - Haraszti, Márton A1 - Pásztor, Szabolcs A1 - Bóta, Attila A1 - András Wacha A1 - Süvegh, Károly A1 - Iván, Béla KW - no-peer-review VL - 121 ER - TY - JOUR T1 - Effects of ursolic acid on the structural and morphological behaviours of dipalmitoyl lecithin vesicles JF - Biochimica et Biophysica Acta (BBA) - Biomembranes Y1 - 2015 A1 - Lőrincz, András A1 - Mihály, Judith A1 - Németh, Csaba A1 - András Wacha A1 - Bóta, Attila KW - DPPC KW - Freeze-fractured transmission electron-microscopy (FF-TEM) KW - Kratky camera KW - Non-bilayer lipid structure KW - peer-reviewed KW - Small- and wide-angle X-ray scattering (SWAXS) KW - Ursolic acid AB -

Effects of ursolic acid on the structural and morphological characteristics of dipalmitoyl lecithin(DPPC)-water system was studied by using differential scanning calorimetry (DSC), small- and wide-angle X-ray scattering (SWAXS), freeze-fracture method combined with transmission electron-microscopy (FF-TEM) and infrared spectroscopy (FT-IR). The surface of the uncorrelated lipid system is rippled or grained and a huge number of small, presumably unilamellar vesicles are present if the UA/DPPC molar ratio is 0.1 mol/mol or higher. Besides the destroyed layer packing of regular multilamellar vesicles, non-bilayer (e.g. cubic or hexagonal) local structures are evidenced by SAXS and FF-TEM methods. The ability of UA to induce non-bilayer structures in hydrated DPPC system originates from the actual geometry form of associated lipid and UA molecules as concluded from the FT-IR measurements and theoretical calculations. Beside numerous beneficial e.g. chemopreventive and chemotherapeutic effect of ursolic acid against cancer, their impact to modify the lipid bilayers can be utilized in liposomal formulations.

VL - 1848 ER - TY - JOUR T1 - Inherently fluorescent and porous zirconia colloids: preparation, characterization and drug adsorption studies JF - J. Mater. Chem. B Y1 - 2015 A1 - Naszályi Nagy, Lívia A1 - Mihály, Judith A1 - Polyák, András A1 - Debreczeni, Balázs A1 - Császár, Barbara A1 - Szigyártó, Imola Csilla A1 - András Wacha A1 - Czégény, Zsuzsanna A1 - Jakab, Emma A1 - Klébert, Szilvia A1 - Drotár, Eszter A1 - Dabasi, G A1 - Bóta, Attila A1 - Balogh, Lajos A1 - Kiss, Éva KW - peer-reviewed AB - Porous, fluorescent zirconia particles of nearly 380 nm diameter were prepared without template molecules or labeling dyes. The porous structure is the result of aggregation-induced particle formation. The inherent fluorescence is assigned to coordinatively unsaturated Zr4+ ions at the sol–{}gel derived ZrO2 surface. After physico-chemical characterization of the native zirconia particles carboxyl and/or amine bearing drug molecules (D,L-\ensuremath{\alpha}-difluoromethylornithine –{} DFMO, ursolic acid –{} UA and doxorubicin –{} DOX) were adsorbed onto their surface, and the products were analyzed with Fourier-transform infrared spectroscopy (FTIR), thermogravimetry (TG), small-angle X-ray scattering (SAXS), fluorimetry and zeta potential vs. pH measurements. We have found that DOX complexes coordinatively unsaturated Zr4+ ions without dislocating them, while carboxyl-bearing drugs interact with basic surface Zr–{}OH sites eliminating some of the carbonate species. The adsorption of UA at the zirconia surface shifts considerably the isoelectric point of the surface and thus provides kinetic stability to the particles at physiological pH. An in vivo biodistribution study in two healthy dogs performed by SPECT/CT detection after 99mTc labeling of the nanocarriers has shown the possibility of drug delivery application. VL - 3 ER - TY - JOUR T1 - Nanoszerkezetek meghatározásának új hazai lehetőségei a CREDO kisszögű röntgenszórásos nagyberendezéssel JF - Magyar Kémikusok Lapja Y1 - 2015 A1 - Bóta, Attila A1 - Varga, Zoltán A1 - András Wacha KW - CREDO VL - 70 SN - 0025-0163, 1588-1199 IS - 10 ER - TY - JOUR T1 - Optimized Pinhole Geometry for Small-Angle Scattering JF - Journal of Applied Crystallography Y1 - 2015 A1 - András Wacha KW - CREDO AB -

In order to make the most from the low photon flux in laboratory small-angle X-ray scattering instruments, the experimental geometry has to be chosen carefully, with special stress on the beam-shaping system. The optimum collimation scheme should enable accurate measurements over the desired range of the scattering variable, while yielding the highest flux and the lowest possible instrumental background. In order to identify the best setting, a phase-space optimization of the collimating scheme is carried out in the present work, including constraints on the beam size at the sample position and on the detector surface. The resulting formulae are implemented in a Python script with a graphical user interface, to aid the planning, construction and daily operation of pinhole small-angle scattering cameras.

VL - 48 IS - 6 ER - TY - JOUR T1 - PDMS-SiO2 hybrid materials – A new insight into the role of Ti and Zr as additives JF - Polymer Y1 - 2015 A1 - Almeida, J. Carlos A1 - András Wacha A1 - Bóta, A. A1 - Almásy, L. A1 - Vaz Fernandes, M. Helena A1 - Margaça, Fernanda M. A. A1 - Miranda Salvado, Isabel M. KW - CREDO KW - Hybrid materials KW - Sol–gel KW - Structure AB - The last two decades have seen a remarkable growth in the design of new hybrid materials applied to different areas, from photonics to biomaterials, together with new coating materials with self-cleaning features. Among the various systems studied, the PDMS-SiO2 system remains as a good basis for further developments by adding other compounds such as transition metals. In this work, a detailed study of the influence of titanium or zirconium in the chemical structure and final microstructure of such hybrids was made. It was concluded that, due to the lower reactivity of the titanium alkoxide during the sol–gel preparation process, titanium is preferably located on the surface of secondary particles of silica, unlike the zirconium, which being more reactive, positions on the surface of the primary particles. This difference leads to xerogels with dissimilar characteristics and morphologies. VL - 72 SN - 0032-3861 UR - http://www.sciencedirect.com/science/article/pii/S0032386115300732 JO - Polymer ER - TY - JOUR T1 - Physicochemical characterization of artificial nanoerythrosomes derived from erythrocyte ghost membranes JF - Colloids and Surfaces B: Biointerfaces Y1 - 2015 A1 - Deák, Róbert A1 - Mihály, Judith A1 - Szigyártó, Imola Cs. A1 - András Wacha A1 - Lelkes, Gábor A1 - Bóta, Attila KW - CREDO KW - Erythrocyte KW - Freeze fracture TEM KW - Infrared spectroscopy KW - Nanoerythrosomes KW - Protein to lipid ratio KW - Small angle X-ray scattering (SAXS) KW - Vesicles AB - Colloidal stabile nanoerythrosomes with 200 nm average diameter were formed from hemoglobin-free erythrocyte ghost membrane via sonication and membrane extrusion. The incorporation of extra lipid (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC), added to the sonicated ghosts, caused significant changes in the thermotropic character of the original membranes. As a result of the increased DPPC ratio the chain melting of the hydrated DPPC system and the characteristic small angle X-ray scattering (SAXS) of the lipid bilayers appeared. Significant morphological changes were followed by transmission electron microscopy combined with freeze fracture method (FF-TEM). After the ultrasonic treatment the large entities of erythrocyte ghosts transformed into nearly spherical nanoerythrosomes with diameters between 100 and 300 nm and at the same time a great number of 10–30 nm large membrane proteins or protein clusters were dispersed in the aqueous medium. The infrared spectroscopy (FT-IR) pointed out, that the sonication did not cause changes in the secondary structures of the membrane proteins under our preparation conditions. About fivefold of extra lipid – compared to the lipid content of the original membrane – caused homogeneous dispersion of nanoerythrosomes however the shape of the vesicles was not uniform. After the addition of about tenfold of DPPC, monoform and monodisperse nanoerythrosomes became typical. The outer surfaces of these roughly spherical objects were frequently polygonal, consisting of a net of pentagons and hexagons. VL - 135 SN - 0927-7765 UR - http://www.sciencedirect.com/science/article/pii/S0927776515301004 JO - Colloids and Surfaces B: Biointerfaces ER - TY - JOUR T1 - The supramolecular chemistry of gold and l-cysteine: Formation of photoluminescent, orange-emitting assemblies with multilayer structure JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects Y1 - 2015 A1 - Söptei, Balázs A1 - Mihály, Judith A1 - Szigyártó, Imola Cs. A1 - András Wacha A1 - Németh, Csaba A1 - Bertóti, Imre A1 - May, Zoltán A1 - Baranyai, Péter A1 - Sajó, István E. A1 - Bóta, Attila KW - CREDO VL - 470 UR - http://linkinghub.elsevier.com/retrieve/pii/S092777571500076X ER - TY - JOUR T1 - Synthesis of Poly}(methyl methacrylate)-poly(poly(ethylene glycol) methacrylate)-polyisobutylene ABCBA Pentablock Copolymers} by Combining Quasiliving Carbocationic} and Atom Transfer Radical Polymerizations} and Characterization Thereof} JF - Journal of Macromolecular Science, Part A Y1 - 2015 A1 - Szabó, Ákos A1 - András Wacha A1 - Thomann, Ralf A1 - Szarka, Györgyi A1 - Bóta, Attila A1 - Iván, Béla KW - Kratky camera KW - peer-reviewed VL - 52 ER - TY - JOUR T1 - Szervetlen gyógyszerhordozó nanorészecskék el\H oáll{ítása és jellemzése JF - Magyar Kémiai Folyóirat - Kémiai Közlemények Y1 - 2015 A1 - Nagyné Naszályi, Lívia A1 - Pálmai, Marcell A1 - Peth\H o, Adrienn A1 - Császár, Barbara A1 - Polyák, András A1 - Szigyártó, Imola Csilla A1 - Mihály, Judith A1 - András Wacha A1 - L\H orincz, András KW - no-peer-review VL - 121 ER - TY - JOUR T1 - CREDO: a new general-purpose laboratory instrument for small-angle X-ray scattering JF - Journal of Applied CrystallographyJournal of Applied Crystallography Y1 - 2014 A1 - András Wacha A1 - Varga, Zoltán A1 - Bóta, Attila VL - 47 SN - 1600-5767 UR - http://scripts.iucr.org/cgi-bin/paper?S1600576714019918 IS - 5 JO - CREDO ER - TY - JOUR T1 - Effect of metal oxide on surface area and pore size of water-dispersible colloids from three German silt loam topsoils JF - Geoderma Y1 - 2014 A1 - Jiang, Canlan A1 - Séquaris, Jean-Marie A1 - András Wacha A1 - Bóta, Attila A1 - Vereecken, Harry A1 - Klumpp, Erwin KW - CREDO VL - 235-236 UR - http://linkinghub.elsevier.com/retrieve/pii/S0016706114002882 ER - TY - JOUR T1 - Intercalation of Bovine Serum Albumin Coated Gold Clusters Between Phospholipid Bilayers: Temperature-Dependent Behavior of Lipid-AuQC@BSA Assemblies with Red Emission and Superlattice Structure JF - The Journal of Physical Chemistry B Y1 - 2014 A1 - Söptei, Balázs A1 - Mihály, Judith A1 - Visy, Júlia A1 - András Wacha A1 - Bóta, Attila AB -

A method has been developed to encapsulate bovine serum albumin (BSA)-coated gold quantum clusters (AuQC@BSA) in a multilamellar system of dipalmitoylphosphatidylcholine (DPPC). Results have shown that intercalation of AuQC@BSA particles into lipid bilayers occurs in the presence of CaCl2. Intense red photoluminescence emission was observed after encapsulation of the clusters. A well-defined structure was found with periodic distances drastically larger than that in the pure DPPC/water system. Although Ca2+ ions can change the dipole characteristics of the lipid bilayer surface, leading to unbinding between the bilayers of multilamellar DPPC/water system, the repulsion is shielded in the presence of AuQC@BSA particles. A coherent superlattice structure evolves due to mixed Ca2+-DPPC and Ca2+-AuQC@BSA interactions. Studies at different temperatures have suggested a correlation between the luminescence properties of the clusters and phase transition of the lipid layers. The temperature-dependent behavior assumes the connection between the coating and the lipid bilayer surface. Temperature-dependent features of lipid intercalated Au clusters provide new opportunities in their application.

VL - 118 SN - 1520-6106 UR - http://dx.doi.org/10.1021/jp4124138 IS - 14 JO - Intercalation of Bovine Serum Albumin Coated Gold Clusters Between Phospholipid BilayersJ. Phys. Chem. B ER - TY - JOUR T1 - Osmotic shrinkage of sterically stabilized liposomes as revealed by time-resolved small-angle X-ray scattering JF - Journal of Applied Crystallography Y1 - 2014 A1 - Varga, Zoltán A1 - András Wacha A1 - Bóta, Attila VL - 47 SN - 1600-5767 UR - http://scripts.iucr.org/cgi-bin/paper?S1600576713030513 IS - 1 ER - TY - JOUR T1 - Small-angle X-ray scattering experiments and computer simulations to characterise anisotropy of activated carbons prepared from wood JF - CarbonCarbon Y1 - 2011 A1 - András Wacha A1 - Varga, Zoltán A1 - Vainio, Ulla A1 - Hoell, Armin A1 - Bóta, Attila VL - 49 SN - 00086223 UR - http://linkinghub.elsevier.com/retrieve/pii/S0008622311003988 IS - 12 ER -