TY - JOUR AU - Bauer, Andrea Rita AU - Kelemen, Lóránd AU - Nakano, M AU - Totsuka, A AU - Zrínyi, Miklós TI - Fabrication and electrorotation of a novel epoxy based micromotor working in a uniform DC electric field JF - SMART MATERIALS AND STRUCTURES J2 - SMART MATER STRUCT VL - 24 PY - 2015 IS - 10 SN - 0964-1726 DO - 10.1088/0964-1726/24/10/105010 UR - https://m2.mtmt.hu/api/publication/2947175 ID - 2947175 N1 - Department of Biophysics and Radiation Biology, Semmelweis University, Nagyvarad ter 4., Budapest, H-1089, Hungary Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62., Szeged, H-6726, Hungary Intelligent Fluid Control Systems Laboratory, Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan MTA-SE Molecular Biophysics Research Group, Department of Biophysics and Radiation Biology, Semmelweis University, Nagyvarad ter 4., Budapest, H-1089, Hungary Cited By :4 Export Date: 31 March 2021 CODEN: SMSTE LA - English DB - MTMT ER - TY - JOUR AU - Tél, A AU - Bauer, Andrea Rita AU - Varga, Zsófia AU - Zrínyi, Miklós TI - Heat conduction in poly(N-isopropylacrylamide) hydrogels JF - INTERNATIONAL JOURNAL OF THERMAL SCIENCES J2 - INT J THERM SCI VL - 85 PY - 2014 SP - 47 EP - 53 PG - 7 SN - 1290-0729 DO - 10.1016/j.ijthermalsci.2014.06.005 UR - https://m2.mtmt.hu/api/publication/2728527 ID - 2728527 AB - Biological tissues are combination of liquids and fibrous solids, therefore polymer hydrogels can be used as model heat transfer system for soft tissues. The 3D network structure of the polymer prevents the convection and the dominant mechanism becomes heat conduction. The main purpose of the present work is to study the effect of network structure on the thermal conduction behavior of soft gels. Cylindrical poly(N-isopropylacrylamide) gel which shows lower critical solution temperature below which the system is completely miscible, whereas above LCST phase separation accours (LCST, [1]). The LCST temperature of the p(NIPA) gel is denoted by Tph throughout this article and is equal to 35 °C. One dimensional heat transfer through the length of the gel cylinder has been experimentally and theoretically studied. The temperature at the bottom of the gel cylinder was suddenly raised above the phase transition temperature. That part of gel cylinder becomes opaque where the temperature exceeds Tph. This defines a visible front that moves forward in the opposite direction to temperature gradient. It was found that our novel technique can be successfully applied to determine heat conductivity and heat diffusivity of loosely cross-linked hydrogels. The kinetics of the moving turbid front was determined and analyzed on the basis of standard 1-d transient heat equation and Stefan's law [2]. It was found that the presence of network structure increases thermal diffusivity compared to pure water. It was also observed that latent heat influences thermal diffusivity. © 2014 Elsevier Masson SAS. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Csákiné Tombácz, Etelka AU - Szekeres, M AU - Jedlovszky-Hajdú, Angéla AU - Tóth, Ildikó AU - Bauer, Andrea Rita AU - Nesztor, Dániel AU - Nyergesné Illés, Erzsébet AU - Zupkó, István AU - Vékás, L TI - Colloidal stability of carboxylated iron oxide nanomagnets for biomedical use JF - PERIODICA POLYTECHNICA-CHEMICAL ENGINEERING J2 - PERIOD POLYTECH CHEM ENG VL - 58 PY - 2014 IS - Suppl. SP - 3 EP - 10 PG - 8 SN - 0324-5853 DO - 10.3311/PPch.7285 UR - https://m2.mtmt.hu/api/publication/2552130 ID - 2552130 N1 - Department of Physical Chemistry and Materials Science, University of Szeged, Hungary Department of Physical Chemistry and Materials Science, University of Szeged, Hungary Laboratory of Nanochemistry, Semmelweis University, Budapest, Hungary Department of Pharmacodynamics and Biopharmacy, University of Szeged, Hungary Center of Fundamental and Advanced Technical Research, RA-TD, Timisoara, Romania Cited By :11 Export Date: 11 August 2020 Department of Physical Chemistry and Materials Science, University of Szeged, Hungary Department of Physical Chemistry and Materials Science, University of Szeged, Hungary Laboratory of Nanochemistry, Semmelweis University, Budapest, Hungary Department of Pharmacodynamics and Biopharmacy, University of Szeged, Hungary Center of Fundamental and Advanced Technical Research, RA-TD, Timisoara, Romania Cited By :12 Export Date: 21 March 2021 Department of Physical Chemistry and Materials Science, University of Szeged, Hungary Department of Physical Chemistry and Materials Science, University of Szeged, Hungary Laboratory of Nanochemistry, Semmelweis University, Budapest, Hungary Department of Pharmacodynamics and Biopharmacy, University of Szeged, Hungary Center of Fundamental and Advanced Technical Research, RA-TD, Timisoara, Romania Cited By :15 Export Date: 16 September 2021 Funding Agency and Grant Number: OTKA foundationOrszagos Tudomanyos Kutatasi Alapprogramok (OTKA) [NK 84014]; [TAMOP-4.2.2.A-11/1/KONV-2012-0047] Funding text: This work was supported by OTKA (NK 84014) foundation and by TAMOP-4.2.2.A-11/1/KONV-2012-0047 project. Supplement: S LA - English DB - MTMT ER - TY - JOUR AU - Tóth, Ildikó AU - Nyergesné Illés, Erzsébet AU - Bauer, Andrea Rita AU - Nesztor, Dániel AU - Szekeres, Márta AU - Zupkó, István AU - Csákiné Tombácz, Etelka TI - Designed polyelectrolyte shell on magnetite nanocore for dilution-resistant biocompatible magnetic fluids JF - LANGMUIR J2 - LANGMUIR VL - 28 PY - 2012 IS - 48 SP - 16638 EP - 16646 PG - 9 SN - 0743-7463 DO - 10.1021/la302660p UR - https://m2.mtmt.hu/api/publication/2118897 ID - 2118897 N1 - Department of Physical Chemistry and Materials Science, University of Szeged, Aradi Vt. 1, H-6720 Szeged, Hungary Department of Pharmacodynamics and Biopharmacy, University of Szeged, Eötvös u. 1, H-6720 Szeged, Hungary Cited By :44 Export Date: 13 January 2023 CODEN: LANGD Correspondence Address: Szekeres, M.; Department of Physical Chemistry and Materials Science, Aradi Vt. 1, H-6720 Szeged, Hungary; email: szekeres@chem.u-szeged.hu Chemicals/CAS: Acrylic Resins; Biocompatible Materials; Colloids; Magnetite Nanoparticles; Maleates; Salts; maleic acid-methacrylic acid copolymer, 87622-09-1 AB - Magnetite nanoparticles (MNPs) coated with poly(acrylic acid-co- maleic acid) polyelectrolyte (PAM) have been prepared with the aim of improving colloidal stability of core-shell nanoparticles for biomedical applications and enhancing the durability of the coating shells. FTIR-ATR measurements reveal two types of interaction of PAM with MNPs: hydrogen bonding and inner-sphere metal-carboxylate complex formation. The mechanism of the latter is ligand exchange between uncharged -OH groups of the surface and -COO- anionic moieties of the polyelectrolyte as revealed by adsorption and electrokinetic experiments. The aqueous dispersion of PAM@MNP particles (magnetic fluids - MFs) tolerate physiological salt concentration at composition corresponding to the plateau of the high-affinity adsorption isotherm. The plateau is reached at small amount of added PAM and at low concentration of non-adsorbed PAM, making PAM highly efficient for coating MNPs. The adsorbed PAM layer is not desorbed during dilution. The performance of the PAM shell is superior to that of polyacrylic acid (PAA), often used in biocompatible MFs. This is explained by the different adsorption mechanisms, namely metal-carboxylate cannot form in the case of PAA. Molecular- level understanding of the protective shell formation on MNPs presented here improves fundamentally the colloidal techniques used in core-shell nanoparticle production for nanotechnology applications. LA - English DB - MTMT ER - TY - JOUR AU - Jedlovszky-Hajdú, Angéla AU - Szekeres, Márta AU - Tóth, Ildikó AU - Bauer, Andrea Rita AU - Mihály, Judith AU - Zupkó, István AU - Csákiné Tombácz, Etelka TI - Enhanced stability of polyacrylate-coated magnetite nanoparticles in biorelevant media JF - COLLOIDS AND SURFACES B: BIOINTERFACES J2 - COLLOID SURFACE B VL - 94 PY - 2012 SP - 242 EP - 249 PG - 8 SN - 0927-7765 DO - 10.1016/j.colsurfb.2012.01.042 UR - https://m2.mtmt.hu/api/publication/1936082 ID - 1936082 AB - Magnetite nanoparticles (MNPs) were prepared by alkaline hydrolysis of Fe(II) and Fe(III) chlorides. Adsorption of polyacrylic acid (PAA) on MNPs was measured at pH=6.5+/-0.3 and I=0.01M (NaCl) to find the optimal PAA amount for MNP stabilization under physiological conditions. We detected an H-bond formation between magnetite surface groups and PAA by ATR-FTIR measurements, but bonds of metal ion-carboxylate complexes, generally cited in literature, were not identified at the given pH and ionic strength. The dependence of the electrokinetic potential and the aggregation state on the amount of added PAA at various pHs was measured by electrophoretic mobility and dynamic light-scattering methods. The electrokinetic potential of the naked MNPs was low at near physiological pH, but PAA adsorption overcharged the particles. Highly negatively charged, well-stabilized carboxylated MNPs formed via adsorption of PAA in an amount of approximately ten times of that necessary to compensate the original positive charge of the magnetite. Coagulation kinetics experiments revealed gradual enhancement of salt tolerance at physiological pH from approximately 0.001M at no added PAA up to approximately 0.5M at 1.12mmol/g PAA. The PAA-coated MNPs exert no substantial effect on the proliferation of malignant (HeLa) or non-cancerous fibroblast cells (MRC-5) as determined by means of MTT assays. LA - English DB - MTMT ER -