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Vilfan M, Lampret B, Gregorin Ž, Cmok L, Vilfan A, Klepp J, Kohlbrecher J, Hribar Boštjančič P, Lisjak D, Mertelj A. Spontaneous Chiral Symmetry Breaking and Lane Formation in Ferromagnetic Ferrofluids. Small 2023; 19:e2304387. [PMID: 37643398 DOI: 10.1002/smll.202304387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/04/2023] [Indexed: 08/31/2023]
Abstract
Ferromagnetic ferrofluids are synthetic materials consisting of magnetic nanoplatelets dispersed in an isotropic fluid. Their main characteristics are the formation of stable magnetic domains and the presence of macroscopic magnetization even in the absence of a magnetic field. Here, the authors report on the experimental observation of spontaneous stripe formation in a ferromagnetic ferrofluid in the presence of an oscillating external magnetic field. The striped structure is identified as elongated magnetic domains, which exhibit reorientation upon reversal of the magnetic field. The stripes are oriented perpendicular to the magnetic field and are separated by alternating flow lanes. The velocity profile is measured using a space-time correlation technique that follows the motion of the thermally excited fluctuations in the sample. The highest velocities are found in the depleted regions between individual domains and reach values up to several µm s-1 . The fluid in adjacent lanes moves in the opposite directions despite the applied magnetic field being uniform. The formation of bidirectional flow lanes can be explained by alternating rotation of magnetic nanoparticles in neighboring stripes, which indicates spontaneous breaking of the chiral symmetry in the sample.
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Affiliation(s)
- Mojca Vilfan
- J. Stefan Institute, Ljubljana, 1000, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, 1000, Slovenia
| | | | | | - Luka Cmok
- J. Stefan Institute, Ljubljana, 1000, Slovenia
| | - Andrej Vilfan
- J. Stefan Institute, Ljubljana, 1000, Slovenia
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077, Göttingen, Germany
| | - Jürgen Klepp
- Faculty of Physics, University of Vienna, Vienna, 1090, Austria
| | - Joachim Kohlbrecher
- Laboratory for Neutron Scattering and Imaging, PSI, Villigen, 5303, Switzerland
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Čampelj S, Pobrežnik M, Landovsky T, Kovač J, Martin-Samos L, Hamplova V, Lisjak D. The Influence of Catechols on the Magnetization of Iron Oxide Nanoparticles. Nanomaterials (Basel) 2023; 13:1822. [PMID: 37368252 DOI: 10.3390/nano13121822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/02/2023] [Accepted: 06/06/2023] [Indexed: 06/28/2023]
Abstract
In this study, MNPs were functionalized with pyrocatechol (CAT), pyrogallol (GAL), caffeic acid (CAF), and nitrodopamine (NDA) at pH 8 and pH 11. The functionalization of the MNPs was successful, except in the case of NDA at pH 11. The thermogravimetric analyses indicated that the surface concentration of the catechols was between 1.5 and 3.6 molecules/nm2. The saturation magnetizations (Ms) of the functionalized MNPs were higher than the starting material. XPS analyses showed only the presence of Fe(III) ions on the surface, thus refuting the idea of the Fe being reduced and magnetite being formed on the surfaces of the MNPs. Density functional theory (DFT) calculations were performed for two modes of adsorption of CAT onto two model surfaces: plain and adsorption via condensation. The total magnetization of both adsorption modes remained the same, indicating that the adsorption of the catechols does not affect the Ms. The analyses of the size and the size distribution showed an increase in the average size of the MNPs during the functionalization process. This increase in the average size of the MNPs and the reduction in the fraction of the smallest (i.e., <10 nm) MNPs explained the increase in the Ms values.
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Affiliation(s)
| | - Matic Pobrežnik
- CNR-IOM, Democritos National Simulation Center, Istituto Officina dei Materiali, c/o SISSA, Via Bonomea 265, 34136 Trieste, Italy
| | - Tomas Landovsky
- FZU-Institute of Physics of the Czech Academy of Science, Na Slovance 1999/2, 18200 Prague, Czech Republic
| | - Janez Kovač
- "Jožef Stefan" Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Layla Martin-Samos
- CNR-IOM, Democritos National Simulation Center, Istituto Officina dei Materiali, c/o SISSA, Via Bonomea 265, 34136 Trieste, Italy
| | - Vera Hamplova
- FZU-Institute of Physics of the Czech Academy of Science, Na Slovance 1999/2, 18200 Prague, Czech Republic
| | - Darja Lisjak
- "Jožef Stefan" Institute, Jamova 39, 1000 Ljubljana, Slovenia
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Djaniš JP, Periša J, Boštjančič PH, Mihajlovski K, Lazić V, Dramićanin M, Lisjak D. Barium hexaferrite nanoplatelets with polyphenol coatings for versatile applications as a stable, magnetic, and antimicrobial colloid. Colloids Surf B Biointerfaces 2023; 224:113198. [PMID: 36773411 DOI: 10.1016/j.colsurfb.2023.113198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/24/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023]
Abstract
Colloidal stabilization of magnetic nanoparticles is one of the most important steps in the preparation of magnetic nanoparticles for potential biomedical applications. A special kind of magnetic nanoparticle are barium hexaferrite nanoplatelets (BSHF NPLs) with a hexagonal shape and a permanent magnetic moment. One strategy for the stabilization of BHF in aqueous media is to use coatings. In our research, we used an eco-friendly tannic acid, as a coating on BSHF NPLs. As-prepared BSHF NPLs coated with tannic acid were examined with transmission electron microscopy, infrared and UV-Vis spectroscopy, electro-kinetic measurements, and their room-temperature magnetic properties were measured. Stable colloids were tested in two biological complex media and antimicrobial properties of the material were examined. To enhance the antimicrobial properties of our material, we used tannic acid as a platform for the in-situ production of silver on BSHF NPLs. New hybrid material with silver also possesses magnetic properties and excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus.
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Affiliation(s)
- Jelena Papan Djaniš
- Department for the Synthesis of Materials, Jožef Stefan Institute, 1000 Ljubljana, Slovenia; Centre of Excellence for Photoconversion, Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 11351 Belgrade, Serbia.
| | - Jovana Periša
- Centre of Excellence for Photoconversion, Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 11351 Belgrade, Serbia
| | | | - Katarina Mihajlovski
- Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, Belgrade, Serbia
| | - Vesna Lazić
- Centre of Excellence for Photoconversion, Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 11351 Belgrade, Serbia
| | - Miroslav Dramićanin
- Centre of Excellence for Photoconversion, Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 11351 Belgrade, Serbia
| | - Darja Lisjak
- Department for the Synthesis of Materials, Jožef Stefan Institute, 1000 Ljubljana, Slovenia
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Lisjak D, Arčon I, Poberžnik M, Herrero-Saboya G, Tufani A, Mavrič A, Valant M, Boštjančič PH, Mertelj A, Makovec D, Martin-Samos L. Saturation magnetisation as an indicator of the disintegration of barium hexaferrite nanoplatelets during the surface functionalisation. Sci Rep 2023; 13:1092. [PMID: 36658162 PMCID: PMC9852462 DOI: 10.1038/s41598-023-28431-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 01/18/2023] [Indexed: 01/20/2023] Open
Abstract
Barium hexaferrite nanoplatelets (BHF NPLs) are permanent nanomagnets with the magnetic easy axis aligned perpendicular to their basal plane. By combining this specific property with optimised surface chemistry, novel functional materials were developed, e.g., ferromagnetic ferrofluids and porous nanomagnets. We compared the interaction of chemically different phosphonic acids, hydrophobic and hydrophilic with 1-4 phosphonic groups, with BHF NPLs. A decrease in the saturation magnetisation after functionalising the BHF NPLs was correlated with the mass fraction of the nonmagnetic coating, whereas the saturation magnetisation of the NPLs coated with a tetraphosphonic acid at 80 °C was significantly lower than expected. We showed that such a substantial decrease in the saturation magnetisation originates from the disintegration of BHF NPLs, which was observed with atomic-resolution scanning transmission electron microscopy and confirmed by a computational study based on state-of-the-art first-principles calculations. Fe K-edge XANES (X-ray absorption near-edge structure) and EXAFS (Extended X-ray absorption fine structure) combined with Fourier-transformed infrared (FTIR) spectroscopy confirmed the formation of an Fe-phosphonate complex on the partly decomposed NPLs. Comparing our results with other functionalised magnetic nanoparticles confirmed that saturation magnetisation can be exploited to identify the disintegration of magnetic nanoparticles when insoluble disintegration products are formed.
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Affiliation(s)
- Darja Lisjak
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Iztok Arčon
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia ,grid.438882.d0000 0001 0212 6916University of Nova Gorica, 5000 Nova Gorica, Slovenia
| | - Matic Poberžnik
- grid.472635.10000 0004 6476 9521CNR-IOM, Democritos National Simulation Center, Istituto Officina dei Materiali, c/o SiSSA, 34136 Trieste, Italy
| | - Gabriela Herrero-Saboya
- grid.472635.10000 0004 6476 9521CNR-IOM, Democritos National Simulation Center, Istituto Officina dei Materiali, c/o SiSSA, 34136 Trieste, Italy
| | - Ali Tufani
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Andraž Mavrič
- grid.438882.d0000 0001 0212 6916University of Nova Gorica, 5000 Nova Gorica, Slovenia
| | - Matjaz Valant
- grid.438882.d0000 0001 0212 6916University of Nova Gorica, 5000 Nova Gorica, Slovenia
| | - Patricija Hribar Boštjančič
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia ,grid.445211.7Jožef Stefan International Postgraduate School, 1000 Ljubljana, Slovenia
| | - Alenka Mertelj
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Darko Makovec
- grid.11375.310000 0001 0706 0012Jožef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Layla Martin-Samos
- grid.472635.10000 0004 6476 9521CNR-IOM, Democritos National Simulation Center, Istituto Officina dei Materiali, c/o SiSSA, 34136 Trieste, Italy
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Gregorin Ž, Sebastián N, Osterman N, Hribar Boštjančič P, Lisjak D, Mertelj A. Dynamics of domain formation in a ferromagnetic fluid. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Budinski V, Pevec S, Čampelj S, Mertelj A, Lisjak D, Donlagic D. Miniature magneto-optic angular position sensor. Opt Lett 2022; 47:4696-4699. [PMID: 36107066 DOI: 10.1364/ol.470646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
This Letter describes a miniature Fabry-Perot, contactless, magneto-optic sensor for angular position measurement. The sensor utilizes a magneto-optic fluid comprising barium hexaferrite nanoplatelets that become birefringent in the presence of an external magnetic field and a compact fiber-optic sensor system for tracking the liquid's optical axis direction. An efficient temperature compensation system is provided which allows the use of otherwise highly temperature-sensitive magneto-optic liquids. An unambiguous measurement range of 90° and a resolution of better than 0.05° are demonstrated experimentally.
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Küster M, Ludwig F, Eremin A, Boštjančič PH, Lisjak D, Sebastián N, Mertelj A, Nádasi H. Magnetic dynamics in suspensions of ferrimagnetic platelets. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Černič T, Koren M, Majaron B, Ponikvar-Svet M, Lisjak D. Optimisation of Amphiphilic-Polymer Coatings for Improved Chemical Stability of NaYF4-based Upconverting Nanoparticles. Acta Chim Slov 2022; 69:448-457. [PMID: 35861088 DOI: 10.17344/acsi.2021.7336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/21/2022] [Accepted: 03/25/2022] [Indexed: 11/19/2022] Open
Abstract
NaYF4 nanoparticles codoped with Yb3+ and Tm3+ exhibit upconversion fluorescence in near-infrared and visible spectral range. Consequently, such upconverting nanoparticles (UCNPs) can be used as contrast agents in medical diagnostics and bioassays. However, they are not chemically stable in aqueous dispersions, especially in phosphate solutions. Protective amphiphilic-polymer coatings based on poly(maleic anhydride-alt-octadec-1-ene) (PMAO) and bis(hexamethylene)triamine (BHMT) were optimised to improve the chemical stability of UCNPs under simulated physiological conditions. Morphologies of the bare and coated UCNPs was inspected with transmission electron microscopy. All samples showed intense UC fluorescence at ~800 nm, typical for Tm3+. The colloidal stability of aqueous dispersions of bare and coated UCNPs was assessed by dynamic light scattering and measurements of zeta potential. The dissolution of UCNP in phosphate-buffered saline at 37 °C, was assessed potentiometrically by measuring the concentration of the dissolved fluoride. Protection against the dissolution of UCNPs was achieved by PMAO and PMAO crosslinked with BHMT.
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Hribar Boštjančič P, Gregorin Ž, Sebastián N, Osterman N, Lisjak D, Mertelj A. Isotropic to nematic transition in alcohol ferrofluids of barium hexaferrite nanoplatelets. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Lisjak D, Vozlič M, Kostiv U, Horák D, Majaron B, Kralj S, Zajc I, Žiberna L, Ponikvar-Svet M. NaYF 4-based upconverting nanoparticles with optimized phosphonate coatings for chemical stability and viability of human endothelial cells. Methods Appl Fluoresc 2021; 10. [PMID: 34883469 DOI: 10.1088/2050-6120/ac41ba] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 12/09/2021] [Indexed: 01/13/2023]
Abstract
The increasing interest in upconverting nanoparticles (UCNPs) in biodiagnostics and therapy fuels the development of biocompatible UCNPs platforms. UCNPs are typically nanocrystallites of rare-earth fluorides codoped with Yb3+and Er3+or Tm3+. The most studied UCNPs are based on NaYF4but are not chemically stable in water. They dissolve significantly in the presence of phosphates. To prevent any adverse effects on the UCNPs induced by cellular phosphates, the surfaces of UCNPs must be made chemically inert and stable by suitable coatings. We studied the effect of various phosphonate coatings on chemical stability andin vitrocytotoxicity of the Yb3+,Er3+-codoped NaYF4UCNPs in human endothelial cells obtained from cellular line Ea.hy926. Cell viability of endothelial cells was determined using the resazurin-based assay after the short-term (15 min), and long-term (24 h and 48 h) incubations with UCNPs dispersed in cell-culture medium. The coatings were obtained from tertaphosphonic acid (EDTMP), sodium alendronate and poly(ethylene glycol)-neridronate. Regardless of the coating conditions, 1 - 2 nm-thick amorphous surface layers were observed on the UCNPs with transmission electron microscopy. The upconversion fluorescence was measured in the dispersions of all UCNPs. Surafce quenching in aqueous suspensions of the UCNPs was reduced by the coatings. The dissolution degree of the UCNPs was determined from the concentration of dissolved fluoride measured with ion-selective electrode after the ageing of UCNPs in water, physiological buffer (i.e., phosphate-buffered saline-PBS) and cell-culture medium. The phosphonate coatings prepared at 80 °C significantly suppressed the dissolution of UCNPs in PBS while only minor dissolution of bare and coated UCNPs was measured in water and cell-culture medium. The viability of human endothelial cells was significantly reduced when incubated with UCNPs, but it increased with the improved chemical stability of UCNPs by the phosphonate coatings with negligible cytotoxicity when coated with EDTMP at 80 °C.
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Affiliation(s)
- Darja Lisjak
- Jožef Stefan Institute, Department for Materials Synthesis, Jamova 39, 1000 Ljubljana, Slovenia
| | - Maša Vozlič
- Jožef Stefan Institute, Department for Materials Synthesis, Jamova 39, 1000 Ljubljana, Slovenia.,University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Uliana Kostiv
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
| | - Daniel Horák
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
| | - Boris Majaron
- Jožef Stefan Institute, Department of Complex Matter, Jamova 39, 1000 Ljubljana, Slovenia.,University of Ljubljana, Faculty for Mathematics and Physics, Jadranska 13, 1000 Ljubljana, Slovenia
| | - Slavko Kralj
- Jožef Stefan Institute, Department for Materials Synthesis, Jamova 39, 1000 Ljubljana, Slovenia
| | - Irena Zajc
- University of Ljubljana, Faculty of Medicine, Institute of Pharmacology and Experimental Toxicology, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Lovro Žiberna
- University of Ljubljana, Faculty of Medicine, Institute of Pharmacology and Experimental Toxicology, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Maja Ponikvar-Svet
- Jožef Stefan Institute, Department of Inroganic Chemistry and Technology, Jamova 39, 1000 Ljubljana, Slovenia
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Papan J, Boštjančič PH, Mertelj A, Lisjak D. Preparation of Barium-Hexaferrite/Gold Janus Nanoplatelets Using the Pickering Emulsion Method. Nanomaterials (Basel) 2021; 11:2797. [PMID: 34835561 PMCID: PMC8621987 DOI: 10.3390/nano11112797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 11/17/2022]
Abstract
Janus particles, which have two surfaces exhibiting different properties, are promising candidates for various applications. For example, magneto-optic Janus particles could be used for in-vivo cancer imaging, drug delivery, and photothermal therapy. The preparation of such materials on a relatively large scale is challenging, especially if the Janus structure consists of a hard magnetic material like barium hexaferrite nanoplatelets. The focus of this study was to adopt the known Pickering emulsion, i.e., Granick's method, for the preparation of barium-hexaferrite/gold Janus nanoplatelets. The wax-in-water Pickering emulsions were stabilized with a combination of cetyltrimethyl ammonium bromide and barium hexaferrite nanoplatelets at 80 °C. Colloidosomes of solidified wax covered with the barium hexaferrite nanoplatelets formed after cooling the Pickering emulsions to room temperature. The formation and microstructure of the colloidosomes were thoroughly studied by optical and scanning electron microscopy. The process was optimized by various processing parameters, such as the composition of the emulsion system and the speed and time of emulsification. The colloidosomes with the highest surface coverage were used to prepare the Janus nanoplatelets by decorating the exposed surfaces of the barium hexaferrite nanoplatelets with gold nanospheres using mercaptan chemistry. Transmission electron microscopy was used to inspect the barium-hexaferrite/gold Janus nanoplatelets that were prepared for the first time.
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Affiliation(s)
- Jelena Papan
- Department of Complex Matter, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (P.H.B.); (A.M.); (D.L.)
- Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia
| | - Patricija Hribar Boštjančič
- Department of Complex Matter, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (P.H.B.); (A.M.); (D.L.)
- Jožef Stefan International Postgraduate School, Jamova Cesta 39, 1000 Ljubljana, Slovenia
| | - Alenka Mertelj
- Department of Complex Matter, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (P.H.B.); (A.M.); (D.L.)
| | - Darja Lisjak
- Department of Complex Matter, Jožef Stefan Institute, Jamova Cesta 39, 1000 Ljubljana, Slovenia; (P.H.B.); (A.M.); (D.L.)
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Vozlič M, Černič T, Gyergyek S, Majaron B, Ponikvar-Svet M, Kostiv U, Horák D, Lisjak D. Formation of phosphonate coatings for improved chemical stability of upconverting nanoparticles under physiological conditions. Dalton Trans 2021; 50:6588-6597. [PMID: 33899872 DOI: 10.1039/d1dt00304f] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Upconverting nanoparticles (UCNPs) are being extensively investigated for applications in bioimaging because of their ability to emit ultraviolet, visible, and near-infrared light. NaYF4 is one of the most suitable host matrices for producing high-intensity upconversion fluorescence; however, UCNPs based on NaYF4 are not chemically stable in aqueous media. To prevent dissolution, their surfaces should be modified. We studied the formation of protective phosphonate coatings made of ethylenediamine(tetramethylenephosphonic acid), alendronic acid, and poly(ethylene glycol)-neridronate on cubic NaYF4 nanoparticles and hexagonal Yb3+,Er3+-doped upconverting NaYF4 nanoparticles (β-UCNPs). The effects of synthesis temperature and ultrasonic agitation on the quality of the coatings were studied. The formation of the coatings was investigated by transmission electron microscopy, zeta-potential measurements, and infrared spectroscopy. The quality of the phosphonate coatings was examined with respect to preventing the dissolution of the NPs in phosphate-buffered saline (PBS). The dissolution tests were carried out under physiological conditions (37 °C and pH 7.4) for 3 days and were followed by measurements of the dissolved fluoride with an ion-selective electrode. We found that the protection of the phosphonate coatings can be significantly increased by synthesizing them at 80 °C. At the same time, the coatings obtained at this temperature suppressed the surface quenching of the upconversion fluorescence in β-UCNPs.
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Affiliation(s)
- Maša Vozlič
- JoŽef Stefan Institute, Department for Materials Synthesis, Jamova 39, 1000 Ljubljana, Slovenia and Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, 1000 Ljubljana, Slovenia.
| | - Tina Černič
- JoŽef Stefan Institute, Department for Materials Synthesis, Jamova 39, 1000 Ljubljana, Slovenia and JoŽef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia
| | - Sašo Gyergyek
- JoŽef Stefan Institute, Department for Materials Synthesis, Jamova 39, 1000 Ljubljana, Slovenia
| | - Boris Majaron
- JoŽef Stefan Institute, Department of Complex Matter, Jamova 39, 1000 Ljubljana, Slovenia and Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
| | - Maja Ponikvar-Svet
- JoŽef Stefan Institute, Department of Inorganic Chemistry and Technology, Jamova 39, 1000 Ljubljana, Slovenia
| | - Uliana Kostiv
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
| | - Daniel Horák
- Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
| | - Darja Lisjak
- JoŽef Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia
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Rosenberg M, Gregorin Ž, Boštjančič PH, Sebastián N, Lisjak D, Kantorovich SS, Mertelj A, Sánchez PA. The influence of polydispersity on the structural properties of the isotropic phase of magnetic nanoplatelets. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.113293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Goršak T, Drab M, Križaj D, Jeran M, Genova J, Kralj S, Lisjak D, Kralj-Iglič V, Iglič A, Makovec D. Magneto-mechanical actuation of barium-hexaferrite nanoplatelets for the disruption of phospholipid membranes. J Colloid Interface Sci 2020; 579:508-519. [PMID: 32623117 DOI: 10.1016/j.jcis.2020.06.079] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/01/2020] [Accepted: 06/18/2020] [Indexed: 01/09/2023]
Abstract
HYPOTHESIS The magneto-mechanical actuation (MMA) of magnetic nanoparticles with a low-frequency alternating magnetic field (AMF) can be used to destroy cancer cells. So far, MMA was tested on different cells using different nanoparticles and different field characteristics, which makes comparisons and any generalizations about the results of MMA difficult. In this paper we propose the use of giant unilamellar vesicles (GUVs) as a simple model system to study the effect of MMA on a closed lipid bilayer membrane, i.e., a basic building block of any cell. EXPERIMENTS The GUVs were exposed to barium-hexaferrite nanoplatelets (NPLs, ~50 nm wide and 3 nm thick) with unique magnetic properties dominated by a permanent magnetic moment that is perpendicular to the platelet, at different concentrations (1-50 µg/mL) and pH values (4.2-7.4) of the aqueous suspension. The GUVs were observed with an optical microscope while being exposed to a uniaxial AMF (3-100 Hz, 2.2-10.6 mT). FINDINGS When the NPLs were electrostatically attached to the GUV membranes, the MMA induced cyclic fluctuations of the GUVs' shape corresponding to the AMF frequency at the low NPL concentration (1 µm/mL), whereas the GUVs were bursting at the higher concentration (10 µg/mL). Theoretical considerations suggested that the bursting of the GUVs is a consequence of the local action of an assembly of several NPLs, rather than a collective effect of all the absorbed NPLs.
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Affiliation(s)
- Tanja Goršak
- Department for Materials Synthesis, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Mitja Drab
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia
| | - Dejan Križaj
- Laboratory of Bioelectromagnetics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia
| | - Marko Jeran
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia; Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, SI-1000 Ljubljana, Slovenia
| | - Julia Genova
- Institute of Solid State Physics, Bulgarian Academy of Sciences, Tzarigradsko 72, 784 Sofia, Bulgaria
| | - Slavko Kralj
- Department for Materials Synthesis, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Darja Lisjak
- Department for Materials Synthesis, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Veronika Kralj-Iglič
- Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, SI-1000 Ljubljana, Slovenia
| | - Aleš Iglič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia
| | - Darko Makovec
- Department for Materials Synthesis, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
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15
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Lisjak D, Hribar Boštjančič P, Mertelj A, Mavrič A, Valant M, Kovač J, Hudelja H, Kocjan A, Makovec D. Formation of Fe(III)-phosphonate Coatings on Barium Hexaferrite Nanoplatelets for Porous Nanomagnets. ACS Omega 2020; 5:14086-14095. [PMID: 32566875 PMCID: PMC7301540 DOI: 10.1021/acsomega.0c01597] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
Amorphous coatings formed with mono-, di-, and tetra-phosphonic acids on barium hexaferrite (BHF) nanoplatelets using various synthesis conditions. The coatings, synthesized in water with di- or tetra-phosphonic acids, were thicker than that could be expected from the ligand size and the surface coverage, as determined by thermogravimetric analysis. Here, we propose a mechanism for coating formation based on direct evidence of the surface dissolution/precipitation of the BHF nanoplatelets. The partial dissolution of the nanoplatelets was observed with atomic-resolution scanning transmission electron microscopy, and the released Fe(III) ions were detected with energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy in amorphous coating. The strong chemical interaction between the surface Fe(III) ions with phosphonic ligands induces the dissolution of BHF nanoplatelets and the consequent precipitation of the Fe(III)-phosphonates that assemble into a porous coating. The so-obtained porous nanomagnets are highly responsive to a very weak magnetic field (in the order of Earth's magnetic field) at room temperature, which is a major advantage over the classic mesoporous nanomaterials and metal-organo-phosphonic frameworks with only a weak magnetic response at a few kelvins. The combination of porosity with the intrinsic magneto-crystalline anisotropy of BHF can be exploited, for example, as sorbents for heavy metals from contaminated water.
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Affiliation(s)
- Darja Lisjak
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
| | - Patricija Hribar Boštjančič
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
- Jožef
Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia
| | - Alenka Mertelj
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
| | - Andraž Mavrič
- University
of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia
- Institute
of Fundamental and Frontier Sciences, University
of Electronic Science and Technology of China, Chengdu 610054, China
| | - Matjaz Valant
- University
of Nova Gorica, Vipavska 13, 5000 Nova Gorica, Slovenia
- Institute
of Fundamental and Frontier Sciences, University
of Electronic Science and Technology of China, Chengdu 610054, China
| | - Janez Kovač
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
| | - Hermina Hudelja
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
- Jožef
Stefan International Postgraduate School, Jamova 39, 1000 Ljubljana, Slovenia
| | - Andraž Kocjan
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
| | - Darko Makovec
- Jožef
Stefan Institute, Jamova
39, 1000 Ljubljana, Slovenia
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16
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Gyergyek S, Lisjak D, Beković M, Grilc M, Likozar B, Nečemer M, Makovec D. Magnetic Heating of Nanoparticles Applied in the Synthesis of a Magnetically Recyclable Hydrogenation Nanocatalyst. Nanomaterials (Basel) 2020; 10:nano10061142. [PMID: 32532039 PMCID: PMC7353275 DOI: 10.3390/nano10061142] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/25/2020] [Accepted: 06/03/2020] [Indexed: 11/16/2022]
Abstract
Utilization of magnetic nanoparticle-mediated conversion of electromagnetic energy into heat is gaining attention in catalysis as a source of heat needed for a substrate's chemical reaction (electrification of chemical conversions). We demonstrate that rapid and selective heating of magnetic nanoparticles opens a way to the rapid synthesis of a nanocatalyst. Magnetic heating caused rapid reduction of Ru3+ cations in the vicinity of the support material and enabled preparation of a Ru nanoparticle-bearing nanocatalyst. Comparative synthesis conducted under conventional heating revealed significantly faster Ru3+ reduction under magnetic heating. The faster kinetic was ascribed to the higher surface temperature of the support material caused by rapid magnetic heating. The nanocatalyst was rigorously tested in the hydrotreatment of furfural. The activity, selectivity and stability for furfural hydrogenation to furfuryl alcohol, a valuable biobased monomer, remained high even after four magnetic recycles.
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Affiliation(s)
- Sašo Gyergyek
- Department for Materials Synthesis, Jožef Stefan Institute, Jamova 60, 1000 Ljubljana, Slovenia; (D.L.); (D.M.)
- Correspondence:
| | - Darja Lisjak
- Department for Materials Synthesis, Jožef Stefan Institute, Jamova 60, 1000 Ljubljana, Slovenia; (D.L.); (D.M.)
| | - Miloš Beković
- Institute of Electrical Power Engineering, Faculty of Electrical Engineering and Computer Science, University of Maribor, Koroška 46, 2000 Maribor, Slovenia;
| | - Miha Grilc
- Department of Catalysis and Chemical Engineering, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; (M.G.); (B.L.)
| | - Blaž Likozar
- Department of Catalysis and Chemical Engineering, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; (M.G.); (B.L.)
| | - Marijan Nečemer
- Department for Low and Medium Energy Physics, Jožef Stefan Institute, Jamova 60, 1000 Ljubljana, Slovenia;
| | - Darko Makovec
- Department for Materials Synthesis, Jožef Stefan Institute, Jamova 60, 1000 Ljubljana, Slovenia; (D.L.); (D.M.)
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17
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Miklavcic D, Novickij V, Kranjc M, Polajzer T, Haberl Meglic S, Batista Napotnik T, Romih R, Lisjak D. Contactless electroporation induced by high intensity pulsed electromagnetic fields via distributed nanoelectrodes. Bioelectrochemistry 2020; 132:107440. [DOI: 10.1016/j.bioelechem.2019.107440] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/03/2019] [Accepted: 12/05/2019] [Indexed: 12/19/2022]
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18
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Abstract
During hydrothermal synthesis the magnetoplumbite strontium-ferrite nanoplatelets form via the growth of primary discoid nanoplatelets with a new, incredibly complex hexagonal structure.
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Affiliation(s)
- D. Makovec
- Department for Materials Synthesis
- Jožef Stefan Institute
- SI-1000 Ljubljana
- Slovenia
| | - G. Dražić
- Department for Materials Chemistry
- National Institute of Chemistry
- SI-1000 Ljubljana
- Slovenia
| | - S. Gyergyek
- Department for Materials Synthesis
- Jožef Stefan Institute
- SI-1000 Ljubljana
- Slovenia
| | - D. Lisjak
- Department for Materials Synthesis
- Jožef Stefan Institute
- SI-1000 Ljubljana
- Slovenia
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19
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Brence J, Cmok L, Sebastián N, Mertelj A, Lisjak D, Drevensek-Olenik I. Optical second harmonic generation in a ferromagnetic liquid crystal. Soft Matter 2019; 15:8758-8765. [PMID: 31588945 DOI: 10.1039/c9sm01591d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A comparative experimental investigation of the dependence of second harmonic generation (SHG) on an applied external voltage between a standard nematic liquid crystalline material and an analogue ferromagnetic nematic liquid crystalline material was performed by using a fundamental optical beam at an 800 nm wavelength. For the ferromagnetic material, the dependence of SHG on an applied magnetic field was also examined. Three different polarization combinations of the fundamental and the second harmonic radiation were analysed. The SHG signal observed in the former material is attributed to a combination of electric field-induced SHG (EFISHG) and flexoelectric deformation-induced SHG, while the SHG signal observed in the latter material is attributed solely to flexoelectric deformation-induced SHG. The obtained dependences of the SHG signal on the associated optical retardation show that, in the most favourable polarization combination, the two contributions generate about the same effective nonlinear optical susceptibility.
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Affiliation(s)
- Jure Brence
- University of Ljubljana, Faculty of Mathematics and Physics, Jadranska 19, SI-1000, Ljubljana, Slovenia
| | - Luka Cmok
- JoŽef Stefan Institute, Department of Complex Matter, Jamova 39, SI-1000 Ljubljana, Slovenia.
| | - Nerea Sebastián
- JoŽef Stefan Institute, Department of Complex Matter, Jamova 39, SI-1000 Ljubljana, Slovenia.
| | - Alenka Mertelj
- JoŽef Stefan Institute, Department of Complex Matter, Jamova 39, SI-1000 Ljubljana, Slovenia.
| | - Darja Lisjak
- JoŽef Stefan Institute, Department for Materials Synthesis, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Irena Drevensek-Olenik
- University of Ljubljana, Faculty of Mathematics and Physics, Jadranska 19, SI-1000, Ljubljana, Slovenia and JoŽef Stefan Institute, Department of Complex Matter, Jamova 39, SI-1000 Ljubljana, Slovenia.
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20
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Naruta T, Akita T, Uchida Y, Lisjak D, Mertelj A, Nishiyama N. Magnetically controllable random laser in ferromagnetic nematic liquid crystals. Opt Express 2019; 27:24426-24433. [PMID: 31510331 DOI: 10.1364/oe.27.024426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 06/13/2019] [Indexed: 06/10/2023]
Abstract
This paper first reports random laser action in dye-doped ferromagnetic nematic liquid crystals, which act as a randomly distributed cavity. The random laser intensity of the ferromagnetic nematic liquid crystals can be controlled by a weak magnetic field (∼1 mT). Moreover, the magnetic switching of random laser is attributed to the direction and polarization dependent emission of light in the ferromagnetic nematic liquid crystals in an external magnetic field.
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21
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Mertelj A, Lampret B, Lisjak D, Klepp J, Kohlbrecher J, Čopič M. Evolution of nematic and ferromagnetic ordering in suspensions of magnetic nanoplatelets. Soft Matter 2019; 15:5412-5420. [PMID: 31241639 DOI: 10.1039/c9sm00949c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Suspensions of magnetic nanoplatelets in isotropic solvents are very interesting examples of ferrofluids. It has been shown that above a certain concentration ΦNI such suspensions form a ferromagnetic nematic phase, which makes this system a unique example of a dipolar fluid. The formation of a nematic phase is driven by anisotropic electrostatic and long-range dipolar magnetic interactions. Here, we present studies of the evolution of short range positional and orientational magnetic order in suspensions with volume fractions below and above ΦNI, using small angle neutron scattering (SANS). The results show that in the absence of an external magnetic field, short range positional and orientational order already exist at relatively low volume fractions. Polarized SANS revealed that the contribution of ferromagnetic ordering to the formation of the nematic phase is significant. The ferromagnetic correlations can be qualitatively explained by a simple model, which takes into account anisotropic screened electrostatic and dipolar magnetic interactions.
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Affiliation(s)
| | - Borut Lampret
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia and Faculty of Mathematics and Physics, University of Ljubljana, Slovenia
| | - Darja Lisjak
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Jürgen Klepp
- Faculty of Physics, University of Vienna, A-1090 Vienna, Austria
| | - Joachim Kohlbrecher
- Laboratory for Neutron Scattering and Imaging, PSI, CH-5232 Villigen PSI, Switzerland
| | - Martin Čopič
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia
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22
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Goršak T, Makovec D, Javornik U, Belec B, Kralj S, Lisjak D. A functionalization strategy for the dispersion of permanently magnetic barium-hexaferrite nanoplatelets in complex biological media. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.04.051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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23
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Hu J, Gorsak T, Martín Rodríguez E, Calle D, Muñoz‐Ortiz T, Jaque D, Fernández N, Cussó L, Rivero F, Aguilar Torres R, García Solé J, Mertelj A, Makovec D, Desco M, Lisjak D, Alfonso F, Sanz‐Rodríguez F, Ortgies DH. Front Cover: Magnetic Nanoplatelets for High Contrast Cardiovascular Imaging by Magnetically Modulated Optical Coherence Tomography (ChemPhotoChem 7/2019). CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jie Hu
- Xiamen Institute of Rare-earth Materials, Haixi InstitutesChinese Academy of Sciences 258 Duishanxiheng Road, Jimei District Xiamen 361024, Fujian China
| | - Tanja Gorsak
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
- Jožef Stefan International Postgraduate School Ljubljana 1000 Slovenia
| | - Emma Martín Rodríguez
- Fluorescence Imaging Group, Departamento de Física AplicadaUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
| | - Daniel Calle
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
| | - Tamara Muñoz‐Ortiz
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
| | - Daniel Jaque
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
| | - Nuria Fernández
- Fluorescence Imaging Group, Departamento de Fisiología Facultad de Medicina, Avda. Arzobispo Morcillo 2Universidad Autónoma de Madrid 28029 Madrid Spain
| | - Lorena Cussó
- Departamento de Bioingeniería e Ingeniería AeroespacialUniversidad Carlos III de Madrid 28911 Madrid Spain
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) Madrid 28029 Spain
| | - Fernando Rivero
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - Río Aguilar Torres
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - José García Solé
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
| | - Alenka Mertelj
- Jožef Stefan Institute, Department for Complex Matter Ljubljana 1000 Slovenia
| | - Darko Makovec
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
| | - Manuel Desco
- Departamento de Bioingeniería e Ingeniería AeroespacialUniversidad Carlos III de Madrid 28911 Madrid Spain
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) Madrid 28029 Spain
| | - Darja Lisjak
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
| | - Fernando Alfonso
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - Francisco Sanz‐Rodríguez
- Fluorescence Imaging Group, Departamento de BiologíaUniversidad Autónoma de Madrid Madrid 28049 Spain
| | - Dirk H. Ortgies
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
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Hu J, Gorsak T, Martín Rodríguez E, Calle D, Muñoz‐Ortiz T, Jaque D, Fernández N, Cussó L, Rivero F, Aguilar Torres R, García Solé J, Mertelj A, Makovec D, Desco M, Lisjak D, Alfonso F, Sanz‐Rodríguez F, Ortgies DH. Magnetic Nanoplatelets for High Contrast Cardiovascular Imaging by Magnetically Modulated Optical Coherence Tomography. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Jie Hu
- Xiamen Institute of Rare-earth Materials, Haixi InstitutesChinese Academy of Sciences 258 Duishanxiheng Road, Jimei District Xiamen 361024, Fujian China
| | - Tanja Gorsak
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
- Jožef Stefan International Postgraduate School Ljubljana 1000 Slovenia
| | - Emma Martín Rodríguez
- Fluorescence Imaging Group, Departamento de Física AplicadaUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
| | - Daniel Calle
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
| | - Tamara Muñoz‐Ortiz
- Fluorescence Imaging Group, Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
| | - Daniel Jaque
- Fluorescence Imaging Group, Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
| | - Nuria Fernández
- Fluorescence Imaging Group, Departamento de Fisiología, Facultad de Medicina, Avda. Arzobispo Morcillo 2Universidad Autónoma de Madrid 28029 Madrid Spain
| | - Lorena Cussó
- Departamento de Bioingeniería e Ingeniería AeroespacialUniversidad Carlos III de Madrid 28911 Madrid Spain
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) Madrid 28029 Spain
| | - Fernando Rivero
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - Río Aguilar Torres
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - José García Solé
- Fluorescence Imaging Group, Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
| | - Alenka Mertelj
- Jožef Stefan Institute, Department for Complex Matter Ljubljana 1000 Slovenia
| | - Darko Makovec
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
| | - Manuel Desco
- Departamento de Bioingeniería e Ingeniería AeroespacialUniversidad Carlos III de Madrid 28911 Madrid Spain
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) Madrid 28029 Spain
| | - Darja Lisjak
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
| | - Fernando Alfonso
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - Francisco Sanz‐Rodríguez
- Fluorescence Imaging Group, Departamento de BiologíaUniversidad Autónoma de Madrid Madrid 28049 Spain
| | - Dirk H. Ortgies
- Fluorescence Imaging Group, Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
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25
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Hu J, Gorsak T, Martín Rodríguez E, Calle D, Muñoz‐Ortiz T, Jaque D, Fernández N, Cussó L, Rivero F, Aguilar Torres R, García Solé J, Mertelj A, Makovec D, Desco M, Lisjak D, Alfonso F, Sanz‐Rodríguez F, Ortgies DH. Magnetic Nanoplatelets for High Contrast Cardiovascular Imaging by Magnetically Modulated Optical Coherence Tomography. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jie Hu
- Xiamen Institute of Rare-earth Materials, Haixi InstitutesChinese Academy of Sciences 258 Duishanxiheng Road, Jimei District Xiamen 361024, Fujian China
| | - Tanja Gorsak
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
- Jožef Stefan International Postgraduate School Ljubljana 1000 Slovenia
| | - Emma Martín Rodríguez
- Fluorescence Imaging Group, Departamento de Física AplicadaUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
| | - Daniel Calle
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
| | - Tamara Muñoz‐Ortiz
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
| | - Daniel Jaque
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
| | - Nuria Fernández
- Fluorescence Imaging Group, Departamento de Fisiología Facultad de Medicina, Avda. Arzobispo Morcillo 2Universidad Autónoma de Madrid 28029 Madrid Spain
| | - Lorena Cussó
- Departamento de Bioingeniería e Ingeniería AeroespacialUniversidad Carlos III de Madrid 28911 Madrid Spain
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) Madrid 28029 Spain
| | - Fernando Rivero
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - Río Aguilar Torres
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - José García Solé
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
| | - Alenka Mertelj
- Jožef Stefan Institute, Department for Complex Matter Ljubljana 1000 Slovenia
| | - Darko Makovec
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
| | - Manuel Desco
- Departamento de Bioingeniería e Ingeniería AeroespacialUniversidad Carlos III de Madrid 28911 Madrid Spain
- Instituto de Investigación Sanitaria Gregorio Marañón Madrid 28007 Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Madrid 28029 Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM) Madrid 28029 Spain
| | - Darja Lisjak
- Jožef Stefan InstituteDepartment for Materials Synthesis Ljubljana 1000 Slovenia
| | - Fernando Alfonso
- Cardiology Department, Hospital Universitario de la Princesa, IIS-IPUniversidad Autónoma de Madrid Madrid 28006 Spain
| | - Francisco Sanz‐Rodríguez
- Fluorescence Imaging Group, Departamento de BiologíaUniversidad Autónoma de Madrid Madrid 28049 Spain
| | - Dirk H. Ortgies
- Fluorescence Imaging Group Departamento de Física de MaterialesUniversidad Autónoma de Madrid C/ Francisco Tomás y Valiente 7 Madrid 28049 Spain
- Nanobiology GroupInstituto Ramón y Cajal de Investigación Sanitaria IRYCIS Ctra. Colmenar km. 9.100 Madrid 28034 Spain
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26
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Gao S, Fleisch M, Rupp RA, Cmok L, Medle-Rupnik P, Mertelj A, Lisjak D, Zhang X, Drevenšek-Olenik I. Magnetically tunable optical diffraction gratings based on a ferromagnetic liquid crystal. Opt Express 2019; 27:8900-8911. [PMID: 31052701 DOI: 10.1364/oe.27.008900] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/13/2019] [Indexed: 06/09/2023]
Abstract
Transmission optical diffraction gratings composed of periodic slices of a ferromagnetic liquid crystal and a conventional photoresist polymer are demonstrated. Dependence of diffraction efficiencies of various diffraction orders on an in-plane external magnetic field is investigated. It is shown that diffraction properties can be effectively tuned by magnetic fields as low as a few mT. The tuning mechanism is explained in the framework of a simple empirical model and also by numerical simulations based on the rigorous coupled wave analysis (RCWA). The obtained results provide a proof of principle of operation of magnetically tunable liquid crystalline diffractive optical elements applicable in contactless schemes for control of optical signals.
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27
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Oliveira H, Bednarkiewicz A, Falk A, Fröhlich E, Lisjak D, Prina‐Mello A, Resch S, Schimpel C, Vrček IV, Wysokińska E, Gorris HH. Critical Considerations on the Clinical Translation of Upconversion Nanoparticles (UCNPs): Recommendations from the European Upconversion Network (COST Action CM1403). Adv Healthc Mater 2019; 8:e1801233. [PMID: 30536962 DOI: 10.1002/adhm.201801233] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/20/2018] [Indexed: 11/07/2022]
Abstract
The unique photoluminescent properties of upconversion nanoparticles (UCNPs) have attracted worldwide research interest and inspired many bioanalytical applications. The anti-Stokes emission with long luminescence lifetimes, narrow and multiple absorption and emission bands, and excellent photostability enable background-free and multiplexed detection in deep tissues. So far, however, in vitro and in vivo applications of UCNPs are restricted to the laboratory use due to safety concerns. Possible harmful effects may originate from the chemical composition but also from the small size of UCNPs. Potential end users must rely on well-founded safety data. Thus, a risk to benefit assessment of the envisioned combined therapeutic and diagnostic ("theranostic") applications is fundamentally important to bridge the translational gap between laboratory and clinics. The COST Action CM1403 "The European Upconversion Network-From the Design of Photon-Upconverting Nanomaterials to Biomedical Applications" integrates research on UCNPs ranging from fundamental materials synthesis and research, detection instrumentation, biofunctionalization, and bioassay development to toxicity testing. Such an interdisciplinary approach is necessary for a better and safer theranostic use of UCNPs. Here, the status of nanotoxicity research on UCNPs is compared to other nanomaterials, and routes for the translation of UCNPs into clinical applications are delineated.
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Affiliation(s)
- Helena Oliveira
- Department of BiologyCESAM‐Centre for Environmental and Marine StudiesCICECO‐Aveiro Institute of MaterialsUniversity of Aveiro 3810‐193 Aveiro Portugal
| | - Artur Bednarkiewicz
- Institute of Low Temperature and Structure ResearchPolish Academy of Sciences ul.Okolna 2 50422 Wroclaw Poland
- PORT Sp. z o.o. Stablowicka 147 Str. 54‐066 Wroclaw Poland
| | - Andreas Falk
- BioNanoNet Forschungsgesellschaft mbH Steyrergasse 17 8010 Graz Austria
| | - Eleonore Fröhlich
- Center for Medical ResearchMedical University of Graz Stiftingtalstrasse 24 8010 Graz Austria
| | - Darja Lisjak
- Department for Materials SynthesisJožef Stefan Institute Jamova 39 1000 Ljubljana Slovenia
| | - Adriele Prina‐Mello
- LBCAM and Nanomedicine LaboratoryTrinity Translational Medicine InstituteTrinity College Dublin Dublin 8 Republic of Ireland
| | - Susanne Resch
- BioNanoNet Forschungsgesellschaft mbH Steyrergasse 17 8010 Graz Austria
| | - Christa Schimpel
- BioNanoNet Forschungsgesellschaft mbH Steyrergasse 17 8010 Graz Austria
| | - Ivana Vinković Vrček
- Institute for Medical Research and Occupational Health Ksaverska cesta 2 10000 Zagreb Croatia
| | - Edyta Wysokińska
- Hirszfeld Institute of Immunology and Experimental TherapyPolish Academy of Sciences Wrocław Poland
| | - Hans H. Gorris
- Institute of Analytical ChemistryChemo‐ and BiosensorsUniversity of Regensburg 93040 Regensburg Germany
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28
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Sebastian N, Lisjak D, Čopič M, Buchnev O, Mertelj A. Comparison of dynamic behavior of ferroelectric and ferromagnetic nematic suspensions. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2017.11.157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Sebastián N, Osterman N, Lisjak D, Čopič M, Mertelj A. Director reorientation dynamics of ferromagnetic nematic liquid crystals. Soft Matter 2018; 14:7180-7189. [PMID: 30141811 DOI: 10.1039/c8sm01377b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Successful realization of ferromagnetic nematic liquid crystals has opened up the possibility to experimentally study a completely new set of fundamental physical phenomena. In this contribution we present a detailed investigation of some aspects of the static response and the complex dynamics of ferromagnetic liquid crystals under the application of an external magnetic field. Experimental results are then compared with a macroscopic model. Dynamics of the director were measured by optical methods and analyzed in terms of a theoretical macroscopic model. A dissipative cross-coupling coefficient describing the dynamic coupling between the two system order parameters, the magnetization and the nematic director, is needed to explain the results. In this contribution we examine the dependency of this coefficient on material parameters and the saturation magnetization and the liquid crystal host. Despite the complexity of the system, the theoretical description allows for a proper interpretation of the results and is connected to several microscopic aspects of the colloidal suspension.
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Affiliation(s)
- Nerea Sebastián
- J. Stefan Institute, P.O.B 3000, SI-1000 Ljubljana, Slovenia.
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30
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Makovec D, Belec B, Goršak T, Lisjak D, Komelj M, DraŽić G, Gyergyek S. Discrete evolution of the crystal structure during the growth of Ba-hexaferrite nanoplatelets. Nanoscale 2018; 10:14480-14491. [PMID: 30022216 DOI: 10.1039/c8nr03815e] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An understanding of the adaptation of the crystal structure of materials confined at the nanoscale, the influences of their specific structures on the evolution of their morphologies and, finally, their functional properties is essential not only for expanding fundamental knowledge, but also for facilitating the designs of novel nanostructures for diverse technological and medical applications. Here we describe how the distinct structure of barium-hexaferrite nanoplatelets evolves in a stepwise manner in parallel with the development of their size and morphology during hydrothermal synthesis. The nanoplatelets are formed by reactions between Ba- and Fe-hydroxides in an aqueous suspension at temperatures below 80 °C. Scanning-transmission electron microscopy showed that the structure of the as-synthesized, discoid nanoplatelets (∼2.3 nm thick, ∼10 nm wide) terminates at the basal surfaces with Ba-containing planes. However, after subsequent washing of the nanoplatelets with water the top two atomic layers dissolve from the surfaces. The final structure can be represented by a SRS* sequence of the barium-hexaferrite SRS*R* unit cell, where S and R represent a hexagonal (BaFe6O11)2- and a cubic (Fe6O8)2+ structural block, respectively. Due to the stable SRS* structure, the thickness of the primary nanoplatelets remains unchanged up to approximately 150 °C, when some of the primary nanoplatelets start to grow exaggeratedly and their thicknesses increase discretely with the addition of the RS segments to their structure. The SRS* structure of the primary nanoplatelets is too thin for the complete development of magnetic ordering. However, the addition of just one RS segment (SRS*R*S structure) gives the nanoplatelets hard magnetic properties.
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Affiliation(s)
- D Makovec
- Department for Materials Synthesis, JoŽef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
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31
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Potisk T, Mertelj A, Sebastián N, Osterman N, Lisjak D, Brand HR, Pleiner H, Svenšek D. Magneto-optic dynamics in a ferromagnetic nematic liquid crystal. Phys Rev E 2018; 97:012701. [PMID: 29448417 DOI: 10.1103/physreve.97.012701] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Indexed: 06/08/2023]
Abstract
We investigate dynamic magneto-optic effects in a ferromagnetic nematic liquid crystal experimentally and theoretically. Experimentally we measure the magnetization and the phase difference of the transmitted light when an external magnetic field is applied. As a model we study the coupled dynamics of the magnetization, M, and the director field, n, associated with the liquid crystalline orientational order. We demonstrate that the experimentally studied macroscopic dynamic behavior reveals the importance of a dynamic cross-coupling between M and n. The experimental data are used to extract the value of the dissipative cross-coupling coefficient. We also make concrete predictions about how reversible cross-coupling terms between the magnetization and the director could be detected experimentally by measurements of the transmitted light intensity as well as by analyzing the azimuthal angle of the magnetization and the director out of the plane spanned by the anchoring axis and the external magnetic field. We derive the eigenmodes of the coupled system and study their relaxation rates. We show that in the usual experimental setup used for measuring the relaxation rates of the splay-bend or twist-bend eigenmodes of a nematic liquid crystal one expects for a ferromagnetic nematic liquid crystal a mixture of at least two eigenmodes.
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Affiliation(s)
- Tilen Potisk
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
- Department of Physics, University of Bayreuth, 95440 Bayreuth, Germany
| | | | | | - Natan Osterman
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Darja Lisjak
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Helmut R Brand
- Department of Physics, University of Bayreuth, 95440 Bayreuth, Germany
| | - Harald Pleiner
- Max Planck Institute for Polymer Research, 55021 Mainz, Germany
| | - Daniel Svenšek
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
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32
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Medle Rupnik P, Lisjak D, Čopič M, Čopar S, Mertelj A. Field-controlled structures in ferromagnetic cholesteric liquid crystals. Sci Adv 2017; 3:e1701336. [PMID: 28989965 PMCID: PMC5630240 DOI: 10.1126/sciadv.1701336] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 09/13/2017] [Indexed: 05/21/2023]
Abstract
One of the advantages of anisotropic soft materials is that their structures and, consequently, their properties can be controlled by moderate external fields. Whereas the control of materials with uniform orientational order is straightforward, manipulation of systems with complex orientational order is challenging. We show that a variety of structures of an interesting liquid material, which combine chiral orientational order with ferromagnetic one, can be controlled by a combination of small magnetic and electric fields. In the suspensions of magnetic nanoplatelets in chiral nematic liquid crystals, the platelet's magnetic moments orient along the orientation of the liquid crystal and, consequently, the material exhibits linear response to small magnetic fields. In the absence of external fields, orientations of the liquid crystal and magnetization have wound structure, which can be either homogeneously helical, disordered, or ordered in complex patterns, depending on the boundary condition at the surfaces and the history of the sample. We demonstrate that by using different combinations of small magnetic and electric fields, it is possible to control reversibly the formation of the structures in a layer of the material. In such a way, different periodic structures can be explored and some of them may be suitable for photonic applications. The material is also a convenient model system to study chiral magnetic structures, because it is a unique liquid analog of a solid helimagnet.
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Affiliation(s)
| | | | - Martin Čopič
- Jožef Stefan Institute, Ljubljana, Slovenia
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
| | - Simon Čopar
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
| | - Alenka Mertelj
- Jožef Stefan Institute, Ljubljana, Slovenia
- Corresponding author.
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33
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Potisk T, Svenšek D, Brand HR, Pleiner H, Lisjak D, Osterman N, Mertelj A. Dynamic Magneto-optic Coupling in a Ferromagnetic Nematic Liquid Crystal. Phys Rev Lett 2017; 119:097802. [PMID: 28949588 DOI: 10.1103/physrevlett.119.097802] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Indexed: 06/07/2023]
Abstract
Hydrodynamics of complex fluids with multiple order parameters is governed by a set of dynamic equations with many material constants, of which only some are easily measurable. We present a unique example of a dynamic magneto-optic coupling in a ferromagnetic nematic liquid, in which long-range orientational order of liquid crystalline molecules is accompanied by long-range magnetic order of magnetic nanoplatelets. We investigate the dynamics of the magneto-optic response experimentally and theoretically and find out that it is significantly affected by the dissipative dynamic cross-coupling between the nematic and magnetic order parameters. The cross-coupling coefficient determined by fitting the experimental results with a macroscopic theory is of the same order of magnitude as the dissipative coefficient (rotational viscosity) that governs the reorientation of pure liquid crystals.
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Affiliation(s)
- Tilen Potisk
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
- Theoretische Physik III, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Daniel Svenšek
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Helmut R Brand
- Theoretische Physik III, Universität Bayreuth, 95440 Bayreuth, Germany
| | - Harald Pleiner
- Max Planck Institute for Polymer Research, 55021 Mainz, Germany
| | - Darja Lisjak
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Natan Osterman
- Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia
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34
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Mur M, Sofi JA, Kvasić I, Mertelj A, Lisjak D, Niranjan V, Muševič I, Dhara S. Magnetic-field tuning of whispering gallery mode lasing from ferromagnetic nematic liquid crystal microdroplets. Opt Express 2017; 25:1073-1083. [PMID: 28157988 DOI: 10.1364/oe.25.001073] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We report magnetic field tuning of the structure and Whispering Gallery Mode lasing from ferromagnetic nematic liquid crystal micro-droplets. Microlasers were prepared by dispersing a nematic liquid crystal, containing magnetic nanoparticles and fluorescent dye, in a glycerol-lecithin matrix. The droplets exhibit radial director structure, which shows elastic distortion at a very low external magnetic field. The fluorescent dye doped ferromagnetic nematic droplets show Whispering Gallery Mode lasing, which is tunable by the external magnetic field. The tuning of the WGM lasing modes is linear in magnetic field with a wavelength-shift of the order of 1 nm/100 mT. Depending on the lasing geometry, the WGMs are red- or blue-shifted.
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35
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Plohl O, Kraft M, Kovač J, Belec B, Ponikvar-Svet M, Würth C, Lisjak D, Resch-Genger U. Optically Detected Degradation of NaYF 4:Yb,Tm-Based Upconversion Nanoparticles in Phosphate Buffered Saline Solution. Langmuir 2017; 33:553-560. [PMID: 27992232 DOI: 10.1021/acs.langmuir.6b03907] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
In a proof-of-concept study, we assessed different analytical and spectroscopic parameters for stability screening of differently sized β-NaYF4:20 mol % Yb3+, 2 mol % Tm3+ upconversion nanoparticles (UCNPs) exemplarily in the bioanalytically relevant buffer phosphate buffered saline (PBS; pH 7.4) at 37 and 50 °C. This included the potentiometric determination of the amount of released fluoride ions, surface analysis with X-ray photoelectron spectroscopy (XPS), and steady-state and time-resolved fluorescence measurements. Based on these results, the luminescence lifetime of the 800 nm upconversion emission was identified as an optimum parameter for stability screening of UCNPs and changes in particle surface chemistry.
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Affiliation(s)
- Olivija Plohl
- Jožef Stefan Institute , Jamova 39, SI-1000 Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Marco Kraft
- Division 1.10 Biophotonics, Federal Institute of Materials Research and Testing (BAM) , 12489 Berlin, Germany
| | - Janez Kovač
- Jožef Stefan Institute , Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Blaž Belec
- Jožef Stefan Institute , Jamova 39, SI-1000 Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, Jamova 39, SI-1000 Ljubljana, Slovenia
| | | | - Christian Würth
- Division 1.10 Biophotonics, Federal Institute of Materials Research and Testing (BAM) , 12489 Berlin, Germany
| | - Darja Lisjak
- Jožef Stefan Institute , Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Ute Resch-Genger
- Division 1.10 Biophotonics, Federal Institute of Materials Research and Testing (BAM) , 12489 Berlin, Germany
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36
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Plohl O, Kralj S, Majaron B, Fröhlich E, Ponikvar-Svet M, Makovec D, Lisjak D. Amphiphilic coatings for the protection of upconverting nanoparticles against dissolution in aqueous media. Dalton Trans 2017; 46:6975-6984. [DOI: 10.1039/c7dt00529f] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Dissolution of upconverting nanoparticles (β-NaYF4:Yb3+,Tm3+) in PBS was efficiently suppressed by a polymer coating, PMAO cross-linked with BHMT.
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Affiliation(s)
- Olivija Plohl
- Jožef Stefan Institute
- Department for Materials Synthesis
- 1000 Ljubljana
- Slovenia
- Jožef Stefan International Postgraduate School
| | - Slavko Kralj
- Jožef Stefan Institute
- Department for Materials Synthesis
- 1000 Ljubljana
- Slovenia
| | - Boris Majaron
- Jožef Stefan Institute
- Department for Complex Matter
- 1000 Ljubljana
- Slovenia
- Medical University of Graz
| | - Eleonore Fröhlich
- University of Ljubljana
- Faculty of Mathematics and Phyisics
- 1000 Ljubljana
- Slovenia
| | - Maja Ponikvar-Svet
- Jožef Stefan Institute
- Department of Inorganic Chemistry and Technology
- 1000 Ljubljana
- Slovenia
| | - Darko Makovec
- Jožef Stefan Institute
- Department for Materials Synthesis
- 1000 Ljubljana
- Slovenia
| | - Darja Lisjak
- Jožef Stefan Institute
- Department for Materials Synthesis
- 1000 Ljubljana
- Slovenia
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37
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Lisjak D, Plohl O, Vidmar J, Majaron B, Ponikvar-Svet M. Dissolution Mechanism of Upconverting AYF4:Yb,Tm (A = Na or K) Nanoparticles in Aqueous Media. Langmuir 2016; 32:8222-9. [PMID: 27459496 DOI: 10.1021/acs.langmuir.6b02675] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The dissolution of upconverting AYF4:Yb,Tm (A = Na or K) nanoparticles (UCNPs) in aqueous media was systematically studied. UCNPs with a cubic structure and sizes of between 10 and 33 nm were synthesized solvothermally in ethylene glycol at 200 °C. The UCNPs of both compositions showed an upconversion fluorescence emission characteristic of Tm(3+). The effects of the A cation, the particle size, the temperature, the pH, and the composition of the aqueous medium on the dissolution of the UCNPs were evaluated. The degree of dissolution was determined from the fraction of dissolved fluoride (F(-)) using potentiometry. Unexpectedly, the composition of aqueous media had the most significant effect on the dissolution of the UCNPs. The highest degree of dissolution and rate were measured for the phosphate-buffered saline (PBS), which can be explained by the formation of stable lanthanide compounds with phosphates. The degree of dissolution was much lower in water and in the phthalate buffer, which was attributed to the release of F(-) as a result of the hydrolysis of the UCNPs' surfaces.
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Affiliation(s)
- Darja Lisjak
- Department for Materials Synthesis, Jožef Stefan Institute , Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Olivija Plohl
- Department for Materials Synthesis, Jožef Stefan Institute , Jamova 39, SI-1000 Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Janja Vidmar
- Jožef Stefan International Postgraduate School, Jamova 39, SI-1000 Ljubljana, Slovenia
- Department of Environmental Sciences, Jožef Stefan Institute , Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Boris Majaron
- Department of Complex Matter, Jožef Stefan Institute , Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Maja Ponikvar-Svet
- Department of Inorganic Chemistry and Technology, Jožef Stefan Institute , Jamova 39, SI-1000 Ljubljana, Slovenia
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38
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Shuai M, Klittnick A, Shen Y, Smith GP, Tuchband MR, Zhu C, Petschek RG, Mertelj A, Lisjak D, Čopič M, Maclennan JE, Glaser MA, Clark NA. Spontaneous liquid crystal and ferromagnetic ordering of colloidal magnetic nanoplates. Nat Commun 2016; 7:10394. [PMID: 26817823 PMCID: PMC4738347 DOI: 10.1038/ncomms10394] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 12/08/2015] [Indexed: 11/18/2022] Open
Abstract
Ferrofluids are familiar as colloidal suspensions of ferromagnetic nanoparticles in aqueous or organic solvents. The dispersed particles are randomly oriented but their moments become aligned if a magnetic field is applied, producing a variety of exotic and useful magnetomechanical effects. A longstanding interest and challenge has been to make such suspensions macroscopically ferromagnetic, that is having uniform magnetic alignment in the absence of a field. Here we report a fluid suspension of magnetic nanoplates that spontaneously aligns into an equilibrium nematic liquid crystal phase that is also macroscopically ferromagnetic. Its zero-field magnetization produces distinctive magnetic self-interaction effects, including liquid crystal textures of fluid block domains arranged in closed flux loops, and makes this phase highly sensitive, with it dramatically changing shape even in the Earth's magnetic field. Ferromagnetism has been known as a material property of solids since the time of the ancient Greeks. Here, Shuai et al. report that magnetic nanoplates suspended in a simple solvent can spontaneously align to form a ferromagnetic liquid, capable of both producing and sensing magnetic fields.
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Affiliation(s)
- M Shuai
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - A Klittnick
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - Y Shen
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - G P Smith
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - M R Tuchband
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - C Zhu
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - R G Petschek
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - A Mertelj
- Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - D Lisjak
- Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - M Čopič
- Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia.,Faculty of Mathematics and Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - J E Maclennan
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - M A Glaser
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
| | - N A Clark
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309, USA
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Plohl O, Majaron B, Ponikvar-Svet M, Makovec D, Lisjak D. Influence of the Synthesis Parameters on the Properties of NaYF4:Yb3+,Tm3+ Nanoparticles. Acta Chim Slov 2015; 62:789-95. [PMID: 26680706 DOI: 10.17344/acsi.2015.1508] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Fluorescent nanoparticles, especially fluorides, have received a great deal of interest due to their optical properties, making them suitable for applications in bio-imaging. For this reason they need to exhibit a superior chemical stability in aqueous media. We have studied the influence of the synthesis parameters on the chemical stability of NaYF(4) nanoparticles co-doped with Yb(3+) and Tm(3+). These nanoparticles have different crystal structures, and were synthesized hydrothermally or with thermal decomposition. The samples were characterized with X-ray diffraction and transmission electron microscopy. The up-conversion fluorescence of nanoparticles dispersed in water was measured at 400-900 nm. The partial dissolution of the fluorine in water was detected with an ion-selective electrode for all the samples. The dissolution of the other constituent ions was analysed with an optical emission spectrometer using inductively coupled plasma. The nanoparticles with a hexagonal crystal structure and sizes of around 20 nm that were synthesized with thermal decomposition showed a superior chemical stability in water together with a superior up-conversion fluorescence yield.
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Ferk G, Krajnc P, Hamler A, Mertelj A, Cebollada F, Drofenik M, Lisjak D. Monolithic Magneto-Optical Nanocomposites of Barium Hexaferrite Platelets in PMMA. Sci Rep 2015; 5:11395. [PMID: 26066069 PMCID: PMC4464329 DOI: 10.1038/srep11395] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/20/2015] [Indexed: 12/01/2022] Open
Abstract
The incorporation of magnetic barium hexaferrite nanoparticles in a transparent polymer matrix of poly(methyl methacrylate) (PMMA) is reported for the first time. The barium hexaferrite nanoplatelets doped with Sc3+, i.e., BaSc0.5Fe11.5O12 (BaHF), having diameters in the range 20 to 130 nm and thicknesses of approximately 5 nm, are synthesized hydrothermally and stabilized in 1-butanol with dodecylbenzenesulfonic acid. This method enables the preparation of monolithic nanocomposites by admixing the BaHF suspension into a liquid monomer, followed by in-situ, bulk free-radical polymerization. The PMMA retains its transparency for loadings of BaHF nanoparticles up to 0.27 wt.%, meaning that magnetically and optically anisotropic, monolithic nanocomposites can be synthesized when the polymerization is carried out in a magnetic field. The excellent dispersion of the magnetic nanoparticles, coupled with a reasonable control over the magnetic properties achieved in this investigation, is encouraging for the magneto-optical applications of these materials.
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Affiliation(s)
- Gregor Ferk
- University of Maribor, Faculty of Chemistry and Chemical Engineering, 2000 Maribor, Slovenia
| | - Peter Krajnc
- University of Maribor, Faculty of Chemistry and Chemical Engineering, 2000 Maribor, Slovenia
| | - Anton Hamler
- University of Maribor, Faculty of Electrical Engineering and Computer Science, 2000 Maribor, Slovenia
| | - Alenka Mertelj
- Jožef Stefan Institute, Department for Complex Matter, 1000 Ljubljana, Slovenia
| | - Federico Cebollada
- Universidad Politécnica de Madrid, POEMMA-CEMDATIC, ETSI de Telecomunicación, 28040 Madrid, Spain
| | - Miha Drofenik
- 1] University of Maribor, Faculty of Chemistry and Chemical Engineering, 2000 Maribor, Slovenia [2] Jožef Stefan Institute, Department for Materials Synthesis, 1000 Ljubljana, Slovenia
| | - Darja Lisjak
- Jožef Stefan Institute, Department for Materials Synthesis, 1000 Ljubljana, Slovenia
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Abstract
The partial dissolution of selected nanoparticles (NaYF4, LaF3 and GdF3) co-doped with Yb3+ and Tm3+ was detected and compared with respect to their size, chemical composition and structure.
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Affiliation(s)
- D. Lisjak
- Jožef Stefan Institute
- SI-1000 Ljubljana
- Slovenia
| | - O. Plohl
- Jožef Stefan Institute
- SI-1000 Ljubljana
- Slovenia
- Jožef Stefan International Postgraduate School
- SI-1000 Ljubljana
| | | | - B. Majaron
- Jožef Stefan Institute
- SI-1000 Ljubljana
- Slovenia
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Mertelj A, Osterman N, Lisjak D, Copič M. Magneto-optic and converse magnetoelectric effects in a ferromagnetic liquid crystal. Soft Matter 2014; 10:9065-9072. [PMID: 25244107 DOI: 10.1039/c4sm01625d] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We have studied the response of ferromagnetic liquid crystals to external magnetic and electric fields, and compared it to the usual response of nematic liquid crystals (NLCs). We have observed effects, which are not present in a pure NLC and are a consequence of the coupling between the nematic director and the magnetization. The electro-optic effect, which is in the ferromagnetic phase the same as in the pure NLC, is accompanied by a converse magnetoelectric effect. The magneto-optic effect differs completely from the one observed in the pure NLC, where it is a quadratic effect and it only appears when a magnetic field larger than a critical field is applied perpendicular to the director. In the ferromagnetic NLC in addition to the response to the perpendicular field, there is also a qualitatively different response to the parallel field. Contrary to the pure NLC no critical field needs to be exceeded for the system to respond to a perpendicular field, but a critical field needs to be exceeded to observe a response to the field parallel to the director and antiparallel to the magnetization. The critical field is in this case two orders of magnitude smaller than the critical field of the magnetic Frederiks transition in the pure NLC. The experimental observations are well described by a simple macroscopic theory.
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Affiliation(s)
- Alenka Mertelj
- J. Stefan Institute, P.O.B. 3000, SI-1001 Ljubljana, Slovenia.
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Lisjak D, Jenuš P, Mertelj A. Influence of the morphology of ferrite nanoparticles on the directed assembly into magnetically anisotropic hierarchical structures. Langmuir 2014; 30:6588-6595. [PMID: 24841592 DOI: 10.1021/la5012633] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The effect of the morphology of ferrite nanoparticles on their assembly in a magnetic field was studied. Thin BaFe12O19 nanoplatelets were compared with isotropic, spherical or octahedral, CoFe2O4 nanoparticles, all of which were synthesized hydrothermally. The nanoplatelets and nanoparticles assembled into a variety of hierarchical structures from stable suspensions during the "drop deposition" and drying in a magnetic field. The alignment of the nanoparticles in the magnetic field was observed in situ with an optical microscope. The morphologies of the nanoparticles and the subsequent assemblies were observed with transmission and scanning electron microscopes, respectively. The magnetic properties of the nanoparticles and the assemblies were measured with a vibrating-sample magnetometer. The BaFe12O19 nanoplatelets aligned in the plane of the substrate and formed several-micrometers-thick, ordered films with a magnetic alignment of approximately 90%. The CoFe2O4 nanoparticles assembled into thick, dense columns with a height of several hundreds of micrometers and showed a magnetic alignment of up to 60%. The differences in the morphologies and the magnetic alignments between the BaFe12O19 and CoFe2O4 hierarchical structures could be explained in terms of the differences in the shape and magnetocrystalline structure of the specific nanoparticles.
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Affiliation(s)
- Darja Lisjak
- Department for Materials Synthesis, Jožef Stefan Institute , Ljubljana, Slovenia
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Mertelj A, Lisjak D, Drofenik M, Čopič M. Ferromagnetism in suspensions of magnetic platelets in liquid crystal. Nature 2013; 504:237-41. [DOI: 10.1038/nature12863] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 11/08/2013] [Indexed: 11/09/2022]
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Emin S, Fanetti M, Abdi FF, Lisjak D, Valant M, van de Krol R, Dam B. Photoelectrochemical properties of cadmium chalcogenide-sensitized textured porous zinc oxide plate electrodes. ACS Appl Mater Interfaces 2013; 5:1113-1121. [PMID: 23323515 DOI: 10.1021/am3027986] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report the photoelectrochemical (PEC) performance of textured porous ZnO and CdX-coated ZnO films (X = S, Se). Porous ZnO films were grown with a platelike morphology on F-doped SnO(2) (FTO) substrates. The growth of ZnO films involves a two-step procedure. In the first step, we electrochemically grew simonkolleite (Zn(5)(OH)(8)Cl(2)·H(2)O) plate films. Annealing of the simonkolleite at 450 °C results in textured porous ZnO films. The as-obtained porous ZnO electrodes were then used in PEC studies. To increase the light-harvesting efficiency, we sensitized these ZnO electrodes with CdS and CdSe quantum dots, using the so-called "successive ion layer adsorption and reaction (SILAR) method". As expected, the photocurrent density systematically increases when going from ZnO to ZnO/CdS to ZnO/CdSe. The highest photocurrent, ∼3.1 mA/cm(2) at 1.2 V vs RHE, was obtained in the CdSe-sensitized ZnO electrodes, because of their enhanced absorption in the visible range. Additionally, quantum efficiency values as high as 90% were achieved with the textured porous ZnO films. These results demonstrate that both CdS and CdSe-sensitized textured porous ZnO electrodes could be potentially useful materials in light-harvesting applications.
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Affiliation(s)
- Saim Emin
- Materials Research Laboratory, University of Nova Gorica, SI-5000 Nova Gorica, Slovenia.
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Affiliation(s)
- Darja Lisjak
- Department for Materials Synthesis, Jožef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Simona Ovtar
- Department for Materials Synthesis, Jožef Stefan Institute, 1000 Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000 Ljubljana, Slovenia
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Abstract
We have studied the preparation of oriented BaFe(12)O(19) films produced using electrophoretic deposition (EPD). Highly anisotropic, platelike BaFe(12)O(19) particles were synthesized under hydrothermal conditions, and from these particles, stable suspensions were prepared in 1-butanol by the addition of dodecylbenzene sulfonic acid as a surfactant. The interplay of the interaction forces between the suspended particles and the forces acting on the particles during the EPD directed the particles' assembly in the plane of the substrate. The most significant effect on the orientation of the films was the diameter-to-thickness ratio of the particles, which was experimentally confirmed with X-ray analyses, electron microscopy, and magnetic measurements. The abnormal grain growth that accompanied the sintering at 1150 °C further improved the overall orientation of the films, which showed highly anisotropic magnetic behavior with a remanent-to-saturation magnetization ratio exceeding 0.8.
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Affiliation(s)
- Darja Lisjak
- Department for Materials Synthesis, Jožef Stefan Institute, Ljubljana, Slovenia.
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Ovtar S, Lisjak D, Drofenik M. Barium hexaferrite suspensions for electrophoretic deposition. J Colloid Interface Sci 2009; 337:456-63. [DOI: 10.1016/j.jcis.2009.05.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 05/15/2009] [Accepted: 05/18/2009] [Indexed: 11/27/2022]
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Primc D, Makovec D, Lisjak D, Drofenik M. Hydrothermal synthesis of ultrafine barium hexaferrite nanoparticles and the preparation of their stable suspensions. Nanotechnology 2009; 20:315605. [PMID: 19597254 DOI: 10.1088/0957-4484/20/31/315605] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The hydrothermal treatment of an appropriate suspension of Ba and Fe hydroxides in the presence of a large excess of OH(-) results in the formation of Ba hexaferrite at temperatures as low as 150 degrees C. This low formation temperature enables the synthesis of uniform, ultrafine Ba hexaferrite nanoparticles. These nanoparticles have a disc-like shape, approximately 10 nm wide, but only approximately 3 nm thick. When the temperature of the hydrothermal treatment is increased, large platelet Ba hexaferrite crystals appear as a consequence of secondary re-crystallization (Ostwald ripening). In this work, this undesired process of secondary re-crystallization has been evaluated. We show that the secondary re-crystallization can be totally suppressed with the use of an oleic acid surfactant. The addition of oleic acid enabled the synthesis of uniform, ultrafine nanoparticles at temperatures up to 240 degrees C. The nanoparticles were hydrophobic and could be suspended in nonpolar liquids to form relatively concentrated ferrofluids. Such stable suspensions of hexaferrite nanoparticles will be technologically important, especially as precursors for the preparation of new nanostructured materials, for example nanocomposites or nanostructured ceramic films.
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Affiliation(s)
- D Primc
- Jozef Stefan Institute, Department for Material Synthesis, Ljubljana, Slovenia.
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