1
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Mehak, Thummer RP, Pandey LM. Surface modified iron-oxide based engineered nanomaterials for hyperthermia therapy of cancer cells. Biotechnol Genet Eng Rev 2023:1-47. [PMID: 36710396 DOI: 10.1080/02648725.2023.2169370] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 01/12/2023] [Indexed: 01/31/2023]
Abstract
Magnetic hyperthermia is emerging as a promising alternative to the currently available cancer treatment modalities. Superparamagnetic iron-oxide nanoparticles (SPIONs) are extensively studied functional nanomaterials for biomedical applications, owing to their tunable physio-chemical properties and magnetic properties. Out of various ferrite classes, spinel and inverse-spinel ferrites are widely used but are affected by particle size distribution, particle shape, particle-particle interaction, geometry, and crystallinity. Notably, their heating ability makes them suitable candidates for heat-mediated cancer cell ablation or hyperthermia therapy. Exposing SPIONs to an externally applied magnetic field of appropriate frequency and intensity causes them to release heat to ablate cancer cells. Majorly, three heating mechanisms are exhibited by magnetic nanomaterials: Nèel relaxation, Brownian relaxation, and hysteresis losses. In SPIONs, Nèel and Brownian relaxations dominate, whereas hysteric losses are negligible. These nanomaterials possess high magnetization values capable of generating heat to ablate cancer cells. Furthermore, surface functionalization of these materials imparts the ability to selectively target cancer cells and deliver cargo to the affected area sparing the normal body cells. The surface of nanoparticles can be functionalized with various physical, chemical, and biological coatings. Moreover, hyperthermia can be applied in combination with other cancer treatment modalities in order to enhance the efficiency of treatment.
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Affiliation(s)
- Mehak
- Bio-interface & Environmental Engineering Lab Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam, India
| | - Rajkumar P Thummer
- Laboratory for Stem Cell Engineering and Regenerative Medicine Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam, India
| | - Lalit M Pandey
- Bio-interface & Environmental Engineering Lab Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam, India
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2
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McKeever C, Aziz M. Effect of Multilayered Structure on the Static and Dynamic Properties of Magnetic Nanospheres. ACS APPLIED MATERIALS & INTERFACES 2022; 14:35177-35183. [PMID: 35879264 PMCID: PMC9354015 DOI: 10.1021/acsami.2c05715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The development of flexible and lightweight electromagnetic interference (EMI)-shielding materials and microwave absorbers requires precise control and optimization of core-shell constituents within composite materials. Here, a theoretical model is proposed to predict the static and dynamic properties of multilayered core-shell particles comprised of exchange-coupled layers, as in the case of a spherical iron core coupled to an oxide shell across a spacer layer. The theory of exchange resonance in homogeneous spheres is shown to be a limiting special case of this more general theory. Nucleation of magnetization reversal occurs through either quasi-uniform or curling magnetization processes in core-shell particles, where a purely homogeneous magnetization configuration is forbidden by the multilayered morphology. The energy is minimized through mixing of modes for specific interface conditions, leading to many inhomogeneous solutions, which grow as 2n with increasing layers, where n represents the number of magnetic layers. The analytical predictions are confirmed using numerical simulations.
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Affiliation(s)
- Conor McKeever
- Department
of Physics and Astronomy, University of
Exeter, Exeter EX4 4QL, United Kingdom
- MaxLLG,
Exeter Science Park, Exeter EX5 2FN, United Kingdom
| | - Mustafa Aziz
- Department
of Engineering, University of Exeter, Exeter EX4 4QF, United Kingdom
- MaxLLG,
Exeter Science Park, Exeter EX5 2FN, United Kingdom
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3
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Das B, Batley JT, Krycka KL, Borchers JA, Quarterman P, Korostynski C, Nguyen M, Kamboj I, Aydil ES, Leighton C. Chemically Induced Magnetic Dead Shells in Superparamagnetic Ni Nanoparticles Deduced from Polarized Small-Angle Neutron Scattering. ACS APPLIED MATERIALS & INTERFACES 2022; 14:33491-33504. [PMID: 35848081 DOI: 10.1021/acsami.2c05558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Advances in the synthesis and characterization of colloidal magnetic nanoparticles (NPs) have yielded great gains in the understanding of their complex magnetic behavior, with implications for numerous applications. Recent work using Ni NPs as a model soft ferromagnetic system, for example, achieved quantitative understanding of the superparamagnetic blocking temperature-particle diameter relationship. This hinged, however, on the critical assumption of a ferromagnetic NP volume lower than the chemical volume due to a non-ferromagnetic dead shell indirectly deduced from magnetometry. Here, we determine both the chemical and magnetic average internal structures of Ni NP ensembles via unpolarized, half-polarized, and fully polarized small-angle neutron scattering (SANS) measurements and analyses coupled with X-ray diffraction and magnetometry. The postulated nanometric magnetic dead shell is not only detected but conclusively identified as a non-ferromagnetic Ni phosphide derived from the trioctylphosphine commonly used in hot-injection colloidal NP syntheses. The phosphide shell thickness is tunable via synthesis temperature, falling to as little as 0.5 nm at 170 °C. Temperature- and magnetic field-dependent polarized SANS measurements additionally reveal essentially bulk-like ferromagnetism in the Ni core and negligible interparticle magnetic interactions, quantitatively supporting prior modeling of superparamagnetism. These findings advance the understanding of synthesis-structure-property relationships in metallic magnetic NPs, point to a simple potential route to ligand-free stabilization, and highlight the power of the currently available suite of polarized SANS measurement and analysis capabilities for magnetic NP science and technology.
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Affiliation(s)
- Bhaskar Das
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Joseph T Batley
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Kathryn L Krycka
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Julie A Borchers
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Patrick Quarterman
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Caroline Korostynski
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - My Nguyen
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Ishita Kamboj
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Eray S Aydil
- Department of Chemical and Biomolecular Engineering, New York University Tandon School of Engineering, Brooklyn, New York 11201, United States
| | - Chris Leighton
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States
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4
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Malyeyev A, Titov I, Dewhurst C, Suzuki K, Honecker D, Michels A. Uniaxial polarization analysis of bulk ferromagnets: theory and first experimental results. J Appl Crystallogr 2022; 55:569-585. [PMID: 35719309 PMCID: PMC9172034 DOI: 10.1107/s1600576722003508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/28/2022] [Indexed: 11/10/2022] Open
Abstract
On the basis of Brown's static equations of micromagnetics, the uniaxial polarization of the scattered neutron beam of a bulk magnetic material is computed. The approach considers a Hamiltonian that takes into account the isotropic exchange interaction, the antisymmetric Dzyaloshinskii–Moriya interaction, magnetic anisotropy, the dipole–dipole interaction and the effect of an applied magnetic field. In the high-field limit, the solutions for the magnetization Fourier components are used to obtain closed-form results for the spin-polarized small-angle neutron scattering (SANS) cross sections and the ensuing polarization. The theoretical expressions are compared with experimental data on a soft magnetic nanocrystalline alloy. The micromagnetic SANS theory provides a general framework for polarized real-space neutron methods, and it may open up a new avenue for magnetic neutron data analysis on magnetic microstructures.
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5
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Socoliuc V, Avdeev MV, Kuncser V, Turcu R, Tombácz E, Vékás L. Ferrofluids and bio-ferrofluids: looking back and stepping forward. NANOSCALE 2022; 14:4786-4886. [PMID: 35297919 DOI: 10.1039/d1nr05841j] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Ferrofluids investigated along for about five decades are ultrastable colloidal suspensions of magnetic nanoparticles, which manifest simultaneously fluid and magnetic properties. Their magnetically controllable and tunable feature proved to be from the beginning an extremely fertile ground for a wide range of engineering applications. More recently, biocompatible ferrofluids attracted huge interest and produced a considerable increase of the applicative potential in nanomedicine, biotechnology and environmental protection. This paper offers a brief overview of the most relevant early results and a comprehensive description of recent achievements in ferrofluid synthesis, advanced characterization, as well as the governing equations of ferrohydrodynamics, the most important interfacial phenomena and the flow properties. Finally, it provides an overview of recent advances in tunable and adaptive multifunctional materials derived from ferrofluids and a detailed presentation of the recent progress of applications in the field of sensors and actuators, ferrofluid-driven assembly and manipulation, droplet technology, including droplet generation and control, mechanical actuation, liquid computing and robotics.
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Affiliation(s)
- V Socoliuc
- Romanian Academy - Timisoara Branch, Center for Fundamental and Advanced Technical Research, Laboratory of Magnetic Fluids, Mihai Viteazu Ave. 24, 300223 Timisoara, Romania.
| | - M V Avdeev
- Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie Str. 6, 141980 Dubna, Moscow Reg., Russia.
| | - V Kuncser
- National Institute of Materials Physics, Bucharest-Magurele, 077125, Romania
| | - Rodica Turcu
- National Institute for Research and Development of Isotopic and Molecular Technologies (INCDTIM), Donat Str. 67-103, 400293 Cluj-Napoca, Romania
| | - Etelka Tombácz
- University of Szeged, Faculty of Engineering, Department of Food Engineering, Moszkvai krt. 5-7, H-6725 Szeged, Hungary.
- University of Pannonia - Soós Ernő Water Technology Research and Development Center, H-8800 Zrínyi M. str. 18, Nagykanizsa, Hungary
| | - L Vékás
- Romanian Academy - Timisoara Branch, Center for Fundamental and Advanced Technical Research, Laboratory of Magnetic Fluids, Mihai Viteazu Ave. 24, 300223 Timisoara, Romania.
- Politehnica University of Timisoara, Research Center for Complex Fluids Systems Engineering, Mihai Viteazul Ave. 1, 300222 Timisoara, Romania
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6
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Honecker D, Bersweiler M, Erokhin S, Berkov D, Chesnel K, Venero DA, Qdemat A, Disch S, Jochum JK, Michels A, Bender P. Using small-angle scattering to guide functional magnetic nanoparticle design. NANOSCALE ADVANCES 2022; 4:1026-1059. [PMID: 36131777 PMCID: PMC9417585 DOI: 10.1039/d1na00482d] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 01/15/2022] [Indexed: 05/14/2023]
Abstract
Magnetic nanoparticles offer unique potential for various technological, biomedical, or environmental applications thanks to the size-, shape- and material-dependent tunability of their magnetic properties. To optimize particles for a specific application, it is crucial to interrelate their performance with their structural and magnetic properties. This review presents the advantages of small-angle X-ray and neutron scattering techniques for achieving a detailed multiscale characterization of magnetic nanoparticles and their ensembles in a mesoscopic size range from 1 to a few hundred nanometers with nanometer resolution. Both X-rays and neutrons allow the ensemble-averaged determination of structural properties, such as particle morphology or particle arrangement in multilayers and 3D assemblies. Additionally, the magnetic scattering contributions enable retrieving the internal magnetization profile of the nanoparticles as well as the inter-particle moment correlations caused by interactions within dense assemblies. Most measurements are used to determine the time-averaged ensemble properties, in addition advanced small-angle scattering techniques exist that allow accessing particle and spin dynamics on various timescales. In this review, we focus on conventional small-angle X-ray and neutron scattering (SAXS and SANS), X-ray and neutron reflectometry, gracing-incidence SAXS and SANS, X-ray resonant magnetic scattering, and neutron spin-echo spectroscopy techniques. For each technique, we provide a general overview, present the latest scientific results, and discuss its strengths as well as sample requirements. Finally, we give our perspectives on how future small-angle scattering experiments, especially in combination with micromagnetic simulations, could help to optimize the performance of magnetic nanoparticles for specific applications.
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Affiliation(s)
- Dirk Honecker
- ISIS Neutron and Muon Facility, Rutherford Appleton Laboratory Didcot OX11 0QX UK
| | - Mathias Bersweiler
- Department of Physics and Materials Science, University of Luxembourg 162A Avenue de La Faïencerie L-1511 Luxembourg Grand Duchy of Luxembourg
| | - Sergey Erokhin
- General Numerics Research Lab Moritz-von-Rohr-Straße 1A D-07745 Jena Germany
| | - Dmitry Berkov
- General Numerics Research Lab Moritz-von-Rohr-Straße 1A D-07745 Jena Germany
| | - Karine Chesnel
- Brigham Young University, Department of Physics and Astronomy Provo Utah 84602 USA
| | - Diego Alba Venero
- ISIS Neutron and Muon Facility, Rutherford Appleton Laboratory Didcot OX11 0QX UK
| | - Asma Qdemat
- Universität zu Köln, Department für Chemie Luxemburger Straße 116 D-50939 Köln Germany
| | - Sabrina Disch
- Universität zu Köln, Department für Chemie Luxemburger Straße 116 D-50939 Köln Germany
| | - Johanna K Jochum
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München Lichtenbergstraße 1 85748 Garching Germany
| | - Andreas Michels
- Department of Physics and Materials Science, University of Luxembourg 162A Avenue de La Faïencerie L-1511 Luxembourg Grand Duchy of Luxembourg
| | - Philipp Bender
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München Lichtenbergstraße 1 85748 Garching Germany
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7
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Oberdick SD, Borchers JA, Krycka KL. Magnetic correlations of iron oxide nanoparticles as probed by polarized SANS in stretched magnetic nanoparticle-elastomer composites. APPLIED PHYSICS LETTERS 2022; 120:10.1063/5.0081922. [PMID: 36620127 PMCID: PMC9813909 DOI: 10.1063/5.0081922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/17/2022] [Indexed: 06/17/2023]
Abstract
We have investigated the magnetic correlations among 7 nm iron oxide nanoparticles embedded in stretched silicone elastomers using polarized Small Angle Neutron Scattering (SANS). The magnetic nanoparticle (MNP)-elastomer composite can be stretched during experiments, and macroscopic deformations cause rearrangement of the iron oxide particles on the nanoscale. Polarized neutrons can be used to nondestructively probe the arrangement of magnetic nanoparticles before and after stretching, so that the relationship between applied stress and nanoscale magnetization can be interrogated. We find that stretching the MNP-elastomer composite past a certain threshold dramatically changes the structural and magnetic morphology of the system. The unstretched sample is modeled well by ~40 nm clusters of ~7 nm particles arranged in a hard sphere packing with a "volume fraction" parameter of 0.3. After the sample is stretched 3× its original size, however, the scattering data can be modeled by smaller, 16 nm clusters with a higher volume fraction of 0.4. We suggest that the effect can be understood by considering a stretching transformation on FCC-like crystallites of iron oxide nanoparticles embedded in an elastomeric medium.
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Affiliation(s)
- S. D. Oberdick
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
- National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - J. A. Borchers
- National Institute of Standards and Technology, NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
| | - K. L. Krycka
- National Institute of Standards and Technology, NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
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8
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Köhler T, Feoktystov A, Petracic O, Kentzinger E, Bhatnagar-Schöffmann T, Feygenson M, Nandakumaran N, Landers J, Wende H, Cervellino A, Rücker U, Kovács A, Dunin-Borkowski RE, Brückel T. Mechanism of magnetization reduction in iron oxide nanoparticles. NANOSCALE 2021; 13:6965-6976. [PMID: 33885498 DOI: 10.1039/d0nr08615k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Iron oxide nanoparticles are presently considered as main work horses for various applications including targeted drug delivery and magnetic hyperthermia. Several questions remain unsolved regarding the effect of size onto their overall magnetic behavior. One aspect is the reduction of magnetization compared to bulk samples. A detailed understanding of the underlying mechanisms of this reduction could improve the particle performance in applications. Here we use a number of complementary experimental techniques including neutron scattering and synchrotron X-ray diffraction to arrive at a consistent conclusion. We confirm the observation from previous studies of a reduced saturation magnetization and argue that this reduction is mainly associated with the presence of antiphase boundaries, which are observed directly using high-resolution transmission electron microscopy and indirectly via an anisotropic peak broadening in X-ray diffraction patterns. Additionally small-angle neutron scattering with polarized neutrons revealed a small non-magnetic surface layer, that is, however, not sufficient to explain the observed loss in magnetization alone.
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Affiliation(s)
- Tobias Köhler
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS at Heinz Maier-Leibnitz Zentrum MLZ, 85748 Garching, Germany.
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9
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Lak A, Disch S, Bender P. Embracing Defects and Disorder in Magnetic Nanoparticles. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002682. [PMID: 33854879 PMCID: PMC8025001 DOI: 10.1002/advs.202002682] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/30/2020] [Indexed: 05/22/2023]
Abstract
Iron oxide nanoparticles have tremendous scientific and technological potential in a broad range of technologies, from energy applications to biomedicine. To improve their performance, single-crystalline and defect-free nanoparticles have thus far been aspired. However, in several recent studies, defect-rich nanoparticles outperform their defect-free counterparts in magnetic hyperthermia and magnetic particle imaging (MPI). Here, an overview on the state-of-the-art of design and characterization of defects and resulting spin disorder in magnetic nanoparticles is presented with a focus on iron oxide nanoparticles. The beneficial impact of defects and disorder on intracellular magnetic hyperthermia performance of magnetic nanoparticles for drug delivery and cancer therapy is emphasized. Defect-engineering in iron oxide nanoparticles emerges to become an alternative approach to tailor their magnetic properties for biomedicine, as it is already common practice in established systems such as semiconductors and emerging fields including perovskite solar cells. Finally, perspectives and thoughts are given on how to deliberately induce defects in iron oxide nanoparticles and their potential implications for magnetic tracers to monitor cell therapy and immunotherapy by MPI.
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Affiliation(s)
- Aidin Lak
- Department of Physics and Center for NanoScienceLMU MunichAmalienstr. 54Munich80799Germany
| | - Sabrina Disch
- Department für ChemieUniversität zu KölnGreinstraße 4‐6Köln50939Germany
| | - Philipp Bender
- Department of Physics and Materials ScienceUniversity of Luxembourg162A avenue de la FaÏencerieLuxembourgL‐1511Grand Duchy of Luxembourg
- Present address:
Heinz Maier‐Leibnitz Zentrum (MLZ)Technische Universität MünchenD‐85748GarchingGermany
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10
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Karpavičius A, Coene A, Bender P, Leliaert J. Advanced analysis of magnetic nanoflower measurements to leverage their use in biomedicine. NANOSCALE ADVANCES 2021; 3:1633-1645. [PMID: 36132562 PMCID: PMC9417518 DOI: 10.1039/d0na00966k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/04/2021] [Indexed: 05/08/2023]
Abstract
Magnetic nanoparticles are an important asset in many biomedical applications ranging from the local heating of tumours to targeted drug delivery towards diseased sites. Recently, magnetic nanoflowers showed a remarkable heating performance in hyperthermia experiments thanks to their complex structure leading to a broad range of magnetic dynamics. To grasp their full potential and to better understand the origin of this unexpected heating performance, we propose the use of Kaczmarz' algorithm in interpreting magnetic characterisation measurements. It has the advantage that no a priori assumptions need to be made on the particle size distribution, contrasting current magnetic interpretation methods that often assume a lognormal size distribution. Both approaches are compared on DC magnetometry, magnetorelaxometry and AC susceptibility characterisation measurements of the nanoflowers. We report that the lognormal distribution parameters vary significantly between data sets, whereas Kaczmarz' approach achieves a consistent and accurate characterisation for all measurement sets. Additionally, we introduce a methodology to use Kaczmarz' approach on distinct measurement data sets simultaneously. It has the advantage that the strengths of the individual characterisation techniques are combined and their weaknesses reduced, further improving characterisation accuracy. Our findings are important for biomedical applications as Kaczmarz' algorithm allows to pinpoint multiple, smaller peaks in the nanostructure's size distribution compared to the monomodal lognormal distribution. The smaller peaks permit to fine-tune biomedical applications with respect to these peaks to e.g. boost heating or to reduce blurring effects in images. Furthermore, the Kaczmarz algorithm allows for a standardised data analysis for a broad range of magnetic nanoparticle samples. Thus, our approach can improve the safety and efficiency of biomedical applications of magnetic nanoparticles, paving the way towards their clinical use.
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Affiliation(s)
| | - Annelies Coene
- Department of Electromechanical, Systems and Metal Engineering, Ghent University Zwijnaarde Belgium
- Cancer Research Institute Ghent Ghent Belgium
| | - Philipp Bender
- Department of Physics and Materials Science, University of Luxembourg Luxembourg Grand Duchy of Luxembourg
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11
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Ghoshani M, Sánchez EH, Lee SS, Singh G, Yaacoub N, Peddis D, Mozaffari M, Binns C, De Toro JA, Normile PS. On the detection of surface spin freezing in iron oxide nanoparticles and its long-term evolution under ambient oxidation. NANOTECHNOLOGY 2021; 32:065704. [PMID: 33108770 DOI: 10.1088/1361-6528/abc50a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Exchange bias (EB) effects linked to surface spin freezing (SSF) are commonly found in iron oxide nanoparticles, while signatures of SSF in low-field temperature-dependent magnetization curves have been much less frequently reported. Here, we present magnetic properties of dense assemblies of similar-sized (∼8 nm diameter) particles synthesized by a magnetite (sample S1) and a maghemite (sample S2) method, and the influence of long-term (4 year) sample aging under ambient conditions on these properties. The size of the EB field of the different sample (fresh or aged) states is found to correlate with (a) whether a low-temperature hump feature signaling the SSF transition is detected in out-of-phase ac susceptibility or zero-field-cooled (ZFC) dc magnetization recorded at low field and with (b) the prominence of irreversibility between FC and ZFC curves recorded at high field. Sample S1 displays a lower magnetization than S2, and it is in S1 where the largest SSF effects are found. These effects are significantly weakened by aging but remain larger than the SSF effects in S2, where the influence of aging is considerably smaller. A non-saturating component due to spin disorder in S1 also weakens with aging, accompanied by, we infer, an increase in the superspin and the radius of the ordered nanoparticle cores. X-ray diffraction and Mössbauer spectroscopy provide indication of maghemite-like stoichiometry in both aged samples as well as thicker disordered particle shells in aged-S1 relative to aged-S2 (crystallographically-disordered and spin-disordered according to diffraction and Mössbauer, respectively). The pronounced diminution in SSF effects with aging in S1 is attributed to a (long-term) transition, caused by ambient oxidation, from magnetite-like to maghemite-like stoichiometry, and a concomitant softening of the spin-disordered shell anisotropy. We assess the impact of this anisotropy on the nature of the blocking of the nanoparticle superspins.
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Affiliation(s)
- M Ghoshani
- Department of Physics, Faculty of Science, University of Isfahan, Isfahan 81746-73441, Iran
- Instituto Regional de Investigación Científica Aplicada (IRICA) and Departamento de Física Aplicada, Universidad de Castilla-La Mancha, E-13071 Ciudad Real, Spain
| | - E H Sánchez
- Instituto Regional de Investigación Científica Aplicada (IRICA) and Departamento de Física Aplicada, Universidad de Castilla-La Mancha, E-13071 Ciudad Real, Spain
| | - S S Lee
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669, Singapore
| | - G Singh
- School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney, NSW 2008, Australia
| | - N Yaacoub
- Institut des Molécules et Materiaux du Mans, CNRS UMR-6283, Université du Maine, F-72085 Le Mans, France
| | - D Peddis
- Istituto di Struttura della Materia, CNR, I-00015 Monterotondo Scalo (RM), Italy
- Dipartimento di Chimica e Chimica Industriale (DCCI), Università of Genova, Via Dopdecanes, I-16134, Genova, Italy
| | - M Mozaffari
- Department of Physics, Faculty of Science, University of Isfahan, Isfahan 81746-73441, Iran
| | - C Binns
- Instituto Regional de Investigación Científica Aplicada (IRICA) and Departamento de Física Aplicada, Universidad de Castilla-La Mancha, E-13071 Ciudad Real, Spain
| | - J A De Toro
- Instituto Regional de Investigación Científica Aplicada (IRICA) and Departamento de Física Aplicada, Universidad de Castilla-La Mancha, E-13071 Ciudad Real, Spain
| | - P S Normile
- Instituto Regional de Investigación Científica Aplicada (IRICA) and Departamento de Física Aplicada, Universidad de Castilla-La Mancha, E-13071 Ciudad Real, Spain
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12
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Hildebrand S, Löwa N, Paysen H, Fratila RM, Reverte-Salisa L, Trakoolwilaiwan T, Niu Z, Kasparis G, Preuss SF, Kosch O, M de la Fuente J, Thanh NTK, Wiekhorst F, Pfeifer A. Quantification of Lipoprotein Uptake in Vivo Using Magnetic Particle Imaging and Spectroscopy. ACS NANO 2021; 15:434-446. [PMID: 33306343 DOI: 10.1021/acsnano.0c03229] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Lipids are a major source of energy for most tissues, and lipid uptake and storage is therefore crucial for energy homeostasis. So far, quantification of lipid uptake in vivo has primarily relied on radioactive isotope labeling, exposing human subjects or experimental animals to ionizing radiation. Here, we describe the quantification of in vivo uptake of chylomicrons, the primary carriers of dietary lipids, in metabolically active tissues using magnetic particle imaging (MPI) and magnetic particle spectroscopy (MPS). We show that loading artificial chylomicrons (ACM) with iron oxide nanoparticles (IONPs) enables rapid and highly sensitive post hoc detection of lipid uptake in situ using MPS. Importantly, by utilizing highly magnetic Zn-doped iron oxide nanoparticles (ZnMNPs), we generated ACM with MPI tracer properties superseding the current gold-standard, Resovist, enabling quantification of lipid uptake from whole-animal scans. We focused on brown adipose tissue (BAT), which dissipates heat and can consume a large part of nutrient lipids, as a model for tightly regulated and inducible lipid uptake. High BAT activity in humans correlates with leanness and improved cardiometabolic health. However, the lack of nonradioactive imaging techniques is an important hurdle for the development of BAT-centered therapies for metabolic diseases such as obesity and type 2 diabetes. Comparison of MPI measurements with iron quantification by inductively coupled plasma mass spectrometry revealed that MPI rivals the performance of this highly sensitive technique. Our results represent radioactivity-free quantification of lipid uptake in metabolically active tissues such as BAT.
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Affiliation(s)
- Staffan Hildebrand
- Institut für Pharmakologie und Toxikologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Norbert Löwa
- 8.23 Metrology for Magnetic Nanoparticles, Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
| | - Hendrik Paysen
- 8.23 Metrology for Magnetic Nanoparticles, Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
| | - Raluca M Fratila
- INMA - Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 28029 Madrid, Spain
| | - Laia Reverte-Salisa
- Institut für Pharmakologie und Toxikologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Thithawat Trakoolwilaiwan
- Biophysics Group, Department of Physics and Astronomy, University College London, London WC1E 6BT, U.K
- UCL Healthcare Biomagnetics Laboratories, 21 Albemarle Street, London W1S 4BS, U.K
| | - Zheming Niu
- Institut für Pharmakologie und Toxikologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Georgios Kasparis
- Biophysics Group, Department of Physics and Astronomy, University College London, London WC1E 6BT, U.K
- UCL Healthcare Biomagnetics Laboratories, 21 Albemarle Street, London W1S 4BS, U.K
| | - Stephanie Franziska Preuss
- Institut für Pharmakologie und Toxikologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Olaf Kosch
- 8.23 Metrology for Magnetic Nanoparticles, Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
| | - Jesus M de la Fuente
- INMA - Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 28029 Madrid, Spain
| | - Nguyen Thi Kim Thanh
- Biophysics Group, Department of Physics and Astronomy, University College London, London WC1E 6BT, U.K
- UCL Healthcare Biomagnetics Laboratories, 21 Albemarle Street, London W1S 4BS, U.K
| | - Frank Wiekhorst
- 8.23 Metrology for Magnetic Nanoparticles, Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, 10587 Berlin, Germany
| | - Alexander Pfeifer
- Institut für Pharmakologie und Toxikologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
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13
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Bender P, Leliaert J, Bersweiler M, Honecker D, Michels A. Unraveling Nanostructured Spin Textures in Bulk Magnets. SMALL SCIENCE 2021. [DOI: 10.1002/smsc.202000003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Philipp Bender
- Department of Physics and Materials Science University of Luxembourg 162A Avenue de la Faïencerie L-1511 Luxembourg Grand Duchy of Luxembourg
| | - Jonathan Leliaert
- Department of Solid State Sciences Ghent University Krijgslaan 281/S1 9000 Ghent Belgium
| | - Mathias Bersweiler
- Department of Physics and Materials Science University of Luxembourg 162A Avenue de la Faïencerie L-1511 Luxembourg Grand Duchy of Luxembourg
| | - Dirk Honecker
- Department of Physics and Materials Science University of Luxembourg 162A Avenue de la Faïencerie L-1511 Luxembourg Grand Duchy of Luxembourg
| | - Andreas Michels
- Department of Physics and Materials Science University of Luxembourg 162A Avenue de la Faïencerie L-1511 Luxembourg Grand Duchy of Luxembourg
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14
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Theis-Bröhl K, Saini A, Wolff M, Dura JA, Maranville BB, Borchers JA. Self-Assembly of Magnetic Nanoparticles in Ferrofluids on Different Templates Investigated by Neutron Reflectometry. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1231. [PMID: 32599954 PMCID: PMC7353075 DOI: 10.3390/nano10061231] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 01/24/2023]
Abstract
In this article we review the process by which magnetite nanoparticles self-assemble onto solid surfaces. The focus is on neutron reflectometry studies providing information on the density and magnetization depth profiles of buried interfaces. Specific attention is given to the near-interface "wetting" layer and to examples of magnetite nanoparticles on a hydrophilic silicon crystal, one coated with (3-Aminopropyl)triethoxysilane, and finally, one with a magnetic film with out-of-plane magnetization.
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Affiliation(s)
- Katharina Theis-Bröhl
- University of Applied Sciences Bremerhaven, An der Karlstadt 8, 27568 Bremerhaven, Germany
| | - Apurve Saini
- Department for Physics and Astronomy, Uppsala University, Lägerhyddsvägen 1, 752 37 Uppsala, Sweden; (A.S.); (M.W.)
| | - Max Wolff
- Department for Physics and Astronomy, Uppsala University, Lägerhyddsvägen 1, 752 37 Uppsala, Sweden; (A.S.); (M.W.)
| | - Joseph A. Dura
- NIST Center for Neutron Research, 100 Bureau Drive, Gaithersburg, MD 20899-6102, USA; (J.A.D.); (B.B.M.); (J.A.B.)
| | - Brian B. Maranville
- NIST Center for Neutron Research, 100 Bureau Drive, Gaithersburg, MD 20899-6102, USA; (J.A.D.); (B.B.M.); (J.A.B.)
| | - Julie A. Borchers
- NIST Center for Neutron Research, 100 Bureau Drive, Gaithersburg, MD 20899-6102, USA; (J.A.D.); (B.B.M.); (J.A.B.)
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15
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Sandler SE, Fellows B, Mefford OT. Best Practices for Characterization of Magnetic Nanoparticles for Biomedical Applications. Anal Chem 2019; 91:14159-14169. [DOI: 10.1021/acs.analchem.9b03518] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Sarah E. Sandler
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Benjamin Fellows
- Department of Bioengineering, University of California at Berkeley, Berkeley, California 94720, United States
| | - O. Thompson Mefford
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
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16
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Mikolasek M, Ridier K, Bessas D, Cerantola V, Félix G, Chaboussant G, Piedrahita-Bello M, Angulo-Cervera E, Godard L, Nicolazzi W, Salmon L, Molnár G, Bousseksou A. Phase Stability of Spin-Crossover Nanoparticles Investigated by Synchrotron Mössbauer Spectroscopy and Small-Angle Neutron Scattering. J Phys Chem Lett 2019; 10:1511-1515. [PMID: 30883126 DOI: 10.1021/acs.jpclett.9b00335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Spin-crossover nanomaterials have been actively studied in the past decade for their potential technological applications in sensing, actuating, and information processing devices. Unfortunately, an increasing number of the metallic centers become inactive at reduced sizes, presumably due to surface effects, limiting their switching ability and thus the scope of applications. Here we report on the investigation of "frozen" metallic centers in nanoparticles (2-80 nm size) of the spin-crossover compound Fe(pyrazine)[Ni(CN)4]. Magnetic measurements reveal both high-spin and low-spin residual fractions at atmospheric pressure. A pressure-induced transition of the high-spin residue is observed at around 1.5 GPa by synchrotron Mössbauer spectroscopy. We show that it is equivalent to a downshift of the transition temperature by ca. 400 K due to the size reduction. Unexpectedly, small-angle neutron scattering experiments demonstrate that these high-spin residual centers are not confined to the surface, which contradicts general theoretical considerations.
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Affiliation(s)
- Mirko Mikolasek
- ESRF-The European Synchrotron , CS40220, 38043 Grenoble Cedex 9, France
| | - Karl Ridier
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Dimitrios Bessas
- ESRF-The European Synchrotron , CS40220, 38043 Grenoble Cedex 9, France
| | - Valerio Cerantola
- ESRF-The European Synchrotron , CS40220, 38043 Grenoble Cedex 9, France
| | - Gautier Félix
- Institut Charles Gerhardt Montpellier, UMR 5253, Ingénierie Moléculaire et Nano-Objets , Université de Montpellier, ENSCM, CNRS , Place E. Bataillon , 34095 Montpellier Cedex 5, France
| | | | - Mario Piedrahita-Bello
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Elias Angulo-Cervera
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Léa Godard
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - William Nicolazzi
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Lionel Salmon
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Gábor Molnár
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
| | - Azzedine Bousseksou
- Laboratoire de Chimie de Coordination , CNRS UPR-8241 and Université de Toulouse, UPS, INP , Toulouse 31013 , France
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17
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Yang MD, Ho CH, Ruta S, Chantrell R, Krycka K, Hovorka O, Chen FR, Lai PS, Lai CH. Magnetic Interaction of Multifunctional Core-Shell Nanoparticles for Highly Effective Theranostics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802444. [PMID: 30311278 PMCID: PMC11284570 DOI: 10.1002/adma.201802444] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 09/04/2018] [Indexed: 05/20/2023]
Abstract
The controlled size and surface treatment of magnetic nanoparticles (NPs) make one-stage combination feasible for enhanced magnetic resonance imaging (MRI) contrast and effective hyperthermia. However, superparamagnetic behavior, essential for avoiding the aggregation of magnetic NPs, substantially limits their performance. Here, a superparamagnetic core-shell structure is developed, which promotes the formation of vortex-like intraparticle magnetization structures in the remanent state, leading to reduced dipolar interactions between two neighboring NPs, while during an MRI scan, the presence of a DC magnetic field induces the formation of NP chains, introducing increased local inhomogeneous dipole fields that enhance relaxivity. The core-shell NPs also reveal an augmented anisotropy, due to exchange coupling to the high anisotropy core, which enhances the specific absorption rate. This in vivo tumor study reveals that the tumor cells can be clearly diagnosed during an MRI scan and the tumor size is substantially reduced through hyperthermia therapy by using the same FePt@iron oxide nanoparticles, realizing the concept of theranostics.
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Affiliation(s)
- Ming-Da Yang
- Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan, 30013, Republic of China
| | - Chien-Hsin Ho
- Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan, 30013, Republic of China
| | - Sergiu Ruta
- Department of Physics, The University of York, York, YO10 5DD, UK
| | - Roy Chantrell
- Department of Physics, The University of York, York, YO10 5DD, UK
| | - Kathryn Krycka
- The Centre for High Resolution Neutron Scattering, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Ondrej Hovorka
- Engineering and the Environment, University of Southampton, Southampton, SO16 7QF, UK
| | - Fu-Rong Chen
- Department of Engineering and System Science, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan, 30013, Republic of China
| | - Ping-Shan Lai
- Department of Chemistry, National Chung Hsing University, No. 145 Xingda Rd., South Dist., Taichung City, 402, Taiwan
| | - Chih-Huang Lai
- Department of Materials Science and Engineering, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan, 30013, Republic of China
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18
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Bender P, Fock J, Hansen MF, Bogart LK, Southern P, Ludwig F, Wiekhorst F, Szczerba W, Zeng LJ, Heinke D, Gehrke N, Díaz MTF, González-Alonso D, Espeso JI, Fernández JR, Johansson C. Influence of clustering on the magnetic properties and hyperthermia performance of iron oxide nanoparticles. NANOTECHNOLOGY 2018; 29:425705. [PMID: 30052525 DOI: 10.1088/1361-6528/aad67d] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Clustering of magnetic nanoparticles can drastically change their collective magnetic properties, which in turn may influence their performance in technological or biomedical applications. Here, we investigate a commercial colloidal dispersion (FeraSpinTMR), which contains dense clusters of iron oxide cores (mean size around 9 nm according to neutron diffraction) with varying cluster size (about 18-56 nm according to small angle x-ray diffraction), and its individual size fractions (FeraSpinTMXS, S, M, L, XL, XXL). The magnetic properties of the colloids were characterized by isothermal magnetization, as well as frequency-dependent optomagnetic and AC susceptibility measurements. From these measurements we derive the underlying moment and relaxation frequency distributions, respectively. Analysis of the distributions shows that the clustering of the initially superparamagnetic cores leads to remanent magnetic moments within the large clusters. At frequencies below 105 rad s-1, the relaxation of the clusters is dominated by Brownian (rotation) relaxation. At higher frequencies, where Brownian relaxation is inhibited due to viscous friction, the clusters still show an appreciable magnetic relaxation due to internal moment relaxation within the clusters. As a result of the internal moment relaxation, the colloids with the large clusters (FS-L, XL, XXL) excel in magnetic hyperthermia experiments.
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Affiliation(s)
- P Bender
- Universidad de Cantabria, E-39005 Santander, Spain
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19
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Oberdick SD, Abdelgawad A, Moya C, Mesbahi-Vasey S, Kepaptsoglou D, Lazarov VK, Evans RFL, Meilak D, Skoropata E, van Lierop J, Hunt-Isaak I, Pan H, Ijiri Y, Krycka KL, Borchers JA, Majetich SA. Spin canting across core/shell Fe 3O 4/Mn xFe 3-xO 4 nanoparticles. Sci Rep 2018; 8:3425. [PMID: 29467424 PMCID: PMC5821856 DOI: 10.1038/s41598-018-21626-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/07/2018] [Indexed: 11/21/2022] Open
Abstract
Magnetic nanoparticles (MNPs) have become increasingly important in biomedical applications like magnetic imaging and hyperthermia based cancer treatment. Understanding their magnetic spin configurations is important for optimizing these applications. The measured magnetization of MNPs can be significantly lower than bulk counterparts, often due to canted spins. This has previously been presumed to be a surface effect, where reduced exchange allows spins closest to the nanoparticle surface to deviate locally from collinear structures. We demonstrate that intraparticle effects can induce spin canting throughout a MNP via the Dzyaloshinskii-Moriya interaction (DMI). We study ~7.4 nm diameter, core/shell Fe3O4/MnxFe3−xO4 MNPs with a 0.5 nm Mn-ferrite shell. Mössbauer spectroscopy, x-ray absorption spectroscopy and x-ray magnetic circular dichroism are used to determine chemical structure of core and shell. Polarized small angle neutron scattering shows parallel and perpendicular magnetic correlations, suggesting multiparticle coherent spin canting in an applied field. Atomistic simulations reveal the underlying mechanism of the observed spin canting. These show that strong DMI can lead to magnetic frustration within the shell and cause canting of the net particle moment. These results illuminate how core/shell nanoparticle systems can be engineered for spin canting across the whole of the particle, rather than solely at the surface.
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Affiliation(s)
- Samuel D Oberdick
- Physics Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.,Applied Physics Division, Physical Measurement Laboratory, NIST, Boulder, CO, 80305, USA
| | - Ahmed Abdelgawad
- Physics Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.,Materials Science and Engineering Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Carlos Moya
- Physics Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | | | - Demie Kepaptsoglou
- SuperSTEM, Sci-Tech Daresbury Campus, Daresbury, WA4 4AD, UK.,Department of Physics, University of York, Heslington, York, YO10 5DD, UK.,The York-JEOL Nanocentre, York Science Park, Heslington, York, YO10 5BR, UK
| | - Vlado K Lazarov
- Department of Physics, University of York, Heslington, York, YO10 5DD, UK
| | - Richard F L Evans
- Department of Physics, University of York, Heslington, York, YO10 5DD, UK
| | - Daniel Meilak
- Department of Physics, University of York, Heslington, York, YO10 5DD, UK
| | - Elizabeth Skoropata
- Physics and Astronomy Department, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Johan van Lierop
- Physics and Astronomy Department, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ian Hunt-Isaak
- Physics and Astronomy Department, Oberlin College, Oberlin, OH, 44074, USA
| | - Hillary Pan
- Physics and Astronomy Department, Oberlin College, Oberlin, OH, 44074, USA
| | - Yumi Ijiri
- Physics and Astronomy Department, Oberlin College, Oberlin, OH, 44074, USA
| | - Kathryn L Krycka
- NIST Center for Neutron Research, NIST, Gaithersburg, Maryland, 20899, USA
| | - Julie A Borchers
- NIST Center for Neutron Research, NIST, Gaithersburg, Maryland, 20899, USA
| | - Sara A Majetich
- Physics Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
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20
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Vivas LG, Yanes R, Michels A. Small-angle neutron scattering modeling of spin disorder in nanoparticles. Sci Rep 2017; 7:13060. [PMID: 29026160 PMCID: PMC5638870 DOI: 10.1038/s41598-017-13457-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 09/22/2017] [Indexed: 11/24/2022] Open
Abstract
Magnetic small-angle neutron scattering (SANS) is a powerful technique for investigating magnetic nanoparticle assemblies in nonmagnetic matrices. For such microstructures, the standard theory of magnetic SANS assumes uniformly magnetized nanoparticles (macrospin model). However, there exist many experimental and theoretical studies which suggest that this assumption is violated: deviations from ellipsoidal particle shape, crystalline defects, or the interplay between various magnetic interactions (exchange, magnetic anisotropy, magnetostatics, external field) may lead to nonuniform spin structures. Therefore, a theoretical framework of magnetic SANS of nanoparticles needs to be developed. Here, we report numerical micromagnetic simulations of the static spin structure and related unpolarized magnetic SANS of a single cobalt nanorod. While in the saturated state the magnetic SANS cross section is (as expected) determined by the particle form factor, significant deviations appear for nonsaturated states; specifically, at remanence, domain-wall and vortex states emerge which result in a magnetic SANS signal that is composed of all three magnetization Fourier components, giving rise to a complex angular anisotropy on a two-dimensional detector. The strength of the micromagnetic simulation methodology is the possibility to decompose the cross section into the individual Fourier components, which allows one to draw important conclusions regarding the fundamentals of magnetic SANS.
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Affiliation(s)
- Laura G Vivas
- Physics and Materials Science Research Unit, University of Luxembourg, 162A avenue de la Faiencerie, Luxembourg, L-1511, Luxembourg.
| | - Rocio Yanes
- Department of Applied Physics, University of Salamanca, Plaza de los Caidos, Salamanca, 37008, Spain
| | - Andreas Michels
- Physics and Materials Science Research Unit, University of Luxembourg, 162A avenue de la Faiencerie, Luxembourg, L-1511, Luxembourg
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21
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Abstract
This article reviews the physics and technology of producing large quantities of highly spin-polarized 3He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized 3He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements.
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Affiliation(s)
- T. R. Gentile
- National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
| | - P. J. Nacher
- Laboratoire Kastler Brossel, ENS-PSL Research University, CNRS, UPMC-Sorbonne Universités, Collège de France, Paris, France
| | - B. Saam
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, USA
| | - T. G. Walker
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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22
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Grutter AJ, Krycka KL, Tartakovskaya EV, Borchers JA, Reddy KSM, Ortega E, Ponce A, Stadler BJH. Complex Three-Dimensional Magnetic Ordering in Segmented Nanowire Arrays. ACS NANO 2017; 11:8311-8319. [PMID: 28700823 DOI: 10.1021/acsnano.7b03488] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A comprehensive three-dimensional picture of magnetic ordering in high-density arrays of segmented FeGa/Cu nanowires is experimentally realized through the application of polarized small-angle neutron scattering. The competing energetics of dipolar interactions, shape anisotropy, and Zeeman energy in concert stabilize a highly tunable spin structure that depends heavily on the applied field and sample geometry. Consequently, we observe ferromagnetic and antiferromagnetic interactions both among wires and between segments within individual wires. The resulting magnetic structure for our nanowire sample in a low field is a fan with magnetization perpendicular to the wire axis that aligns nearly antiparallel from one segment to the next along the wire axis. Additionally, while the low-field interwire coupling is ferromagnetic, application of a field tips the moments toward the nanowire axis, resulting in highly frustrated antiferromagnetic stripe patterns in the hexagonal nanowire lattice. Theoretical calculations confirm these observations, providing insight into the competing interactions and resulting stability windows for a variety of ordered magnetic structures. These results provide a roadmap for designing high-density magnetic nanowire arrays for spintronic device applications.
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Affiliation(s)
- Alexander J Grutter
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Kathryn L Krycka
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Elena V Tartakovskaya
- Institute of Magnetism, NASU of Ukraine , 03142 Kiev, Ukraine
- Kiev National University , Institute of High Technologies, 03022 Kiev, Ukraine
| | - Julie A Borchers
- NIST Center for Neutron Research, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - K Sai Madhukar Reddy
- Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Eduardo Ortega
- Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States
| | - Arturo Ponce
- Department of Physics and Astronomy, University of Texas at San Antonio , San Antonio, Texas 78249, United States
| | - Bethanie J H Stadler
- Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States
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23
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Phan MH, Alonso J, Khurshid H, Lampen-Kelley P, Chandra S, Stojak Repa K, Nemati Z, Das R, Iglesias Ó, Srikanth H. Exchange Bias Effects in Iron Oxide-Based Nanoparticle Systems. NANOMATERIALS 2016; 6:nano6110221. [PMID: 28335349 PMCID: PMC5245749 DOI: 10.3390/nano6110221] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/29/2016] [Accepted: 11/02/2016] [Indexed: 11/16/2022]
Abstract
The exploration of exchange bias (EB) on the nanoscale provides a novel approach to improving the anisotropic properties of magnetic nanoparticles for prospective applications in nanospintronics and nanomedicine. However, the physical origin of EB is not fully understood. Recent advances in chemical synthesis provide a unique opportunity to explore EB in a variety of iron oxide-based nanostructures ranging from core/shell to hollow and hybrid composite nanoparticles. Experimental and atomistic Monte Carlo studies have shed light on the roles of interface and surface spins in these nanosystems. This review paper aims to provide a thorough understanding of the EB and related phenomena in iron oxide-based nanoparticle systems, knowledge of which is essential to tune the anisotropic magnetic properties of exchange-coupled nanoparticle systems for potential applications.
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Affiliation(s)
- Manh-Huong Phan
- Department of Physics, University of South Florida, Tampa, FL 33620, USA.
| | - Javier Alonso
- Department of Physics, University of South Florida, Tampa, FL 33620, USA.
- BCMaterials Building 500, Bizkaia Science and Technology Park, 48160 Derio, Spain.
| | - Hafsa Khurshid
- Department of Physics, University of South Florida, Tampa, FL 33620, USA.
| | | | - Sayan Chandra
- Department of Physics, University of South Florida, Tampa, FL 33620, USA.
| | | | - Zohreh Nemati
- Department of Physics, University of South Florida, Tampa, FL 33620, USA.
| | - Raja Das
- Department of Physics, University of South Florida, Tampa, FL 33620, USA.
| | - Óscar Iglesias
- Department of Fundamental Physics and Institute of Nanoscience and Nanotechnology (In2UB), University of Barcelona, Av. Diagonal 647, 08028 Barcelona, Spain.
| | - Hariharan Srikanth
- Department of Physics, University of South Florida, Tampa, FL 33620, USA.
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24
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Dewhurst CD, Grillo I, Honecker D, Bonnaud M, Jacques M, Amrouni C, Perillo-Marcone A, Manzin G, Cubitt R. The small-angle neutron scattering instrument D33 at the Institut Laue–Langevin. J Appl Crystallogr 2016. [DOI: 10.1107/s1600576715021792] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The D33 small-angle neutron scattering (SANS) instrument at the Institut Laue–Langevin (ILL) is the most recent SANS instrument to be built at the ILL. In a project beginning in 2005 and lasting seven years, the concept has been developed, and the instrument designed, manufactured and installed. D33 was commissioned with neutrons during the second half of 2012, fully entering the ILL user programme in 2013. The scientific case required that D33 should provide a wide dynamic range of measured scattering vector magnitudeq, flexibility with regard to the instrument resolution, and the provision of polarized neutrons and3He spin analysis to facilitate and expand studies in magnetism. In monochromatic mode, a velocity selector and a flexible system of inter-collimation apertures define the neutron beam. A double-chopper system enables a time-of-flight (TOF) mode of operation, allowing an enhanced dynamicqrange (qmax/qmin) and a flexible wavelength resolution. Two large multitube detectors extend the dynamicqrange further, givingqmax/qmin≃ 25 in monochromatic mode and a very largeqmax/qmin> 1000 in TOF mode. The sample zone is large and flexible in configuration, accommodating complex and bulky sample environments, while the position of D33 is such as to allow high magnetic fields at the sample position. The instrument is of general purpose with a performance rivalling that of D22, and is well adapted for SANS studies in scientific disciplines as diverse as solution scattering in biology and soft matter and studies of physics, materials science and magnetism. This article provides a detailed technical description of D33 and its performance and characterization of the individual components, and serves as a technical reference for users of the instrument.
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Magnetic iron oxide nanoparticles: Recent trends in design and synthesis of magnetoresponsive nanosystems. Biochem Biophys Res Commun 2015; 468:442-53. [DOI: 10.1016/j.bbrc.2015.08.030] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 08/08/2015] [Indexed: 01/01/2023]
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Kandasamy G, Maity D. Recent advances in superparamagnetic iron oxide nanoparticles (SPIONs) for in vitro and in vivo cancer nanotheranostics. Int J Pharm 2015; 496:191-218. [PMID: 26520409 DOI: 10.1016/j.ijpharm.2015.10.058] [Citation(s) in RCA: 202] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 10/20/2015] [Accepted: 10/22/2015] [Indexed: 12/15/2022]
Abstract
Recently superparamagnetic iron oxide nanoparticles (SPIONs) have been extensively used in cancer therapy and diagnosis (theranostics) via magnetic targeting, magnetic resonance imaging, etc. due to their remarkable magnetic properties, chemical stability, and biocompatibility. However, the magnetic properties of SPIONs are influenced by various physicochemical and synthesis parameters. So, this review mainly focuses on the influence of spin canting effects, introduced by the variations in size, shape, and organic/inorganic surface coatings, on the magnetic properties of SPIONs. This review also describes the several predominant chemical synthesis procedures and role of the synthesis parameters for monitoring the size, shape, crystallinity and composition of the SPIONs. Moreover, this review discusses about the latest developments of the inorganic materials and organic polymers for encapsulation of the SPIONs. Finally, the most recent advancements of the SPIONs and their nanopackages in combination with other imaging/therapeutic agents have been comprehensively discussed for their effective usage as in vitro and in vivo theranostic agents in cancer treatments.
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Affiliation(s)
- Ganeshlenin Kandasamy
- Nanomaterials Lab, Department of Mechanical Engineering, Shiv Nadar University, Uttar Pradesh 201314, India
| | - Dipak Maity
- Nanomaterials Lab, Department of Mechanical Engineering, Shiv Nadar University, Uttar Pradesh 201314, India.
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Spin-glass-like freezing of inner and outer surface layers in hollow γ-Fe2O3 nanoparticles. Sci Rep 2015; 5:15054. [PMID: 26503506 PMCID: PMC4621521 DOI: 10.1038/srep15054] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 09/16/2015] [Indexed: 11/08/2022] Open
Abstract
Disorder among surface spins is a dominant factor in the magnetic response of magnetic nanoparticle systems. In this work, we examine time-dependent magnetization in high-quality, monodisperse hollow maghemite nanoparticles (NPs) with a 14.8 ± 0.5 nm outer diameter and enhanced surface-to-volume ratio. The nanoparticle ensemble exhibits spin-glass-like signatures in dc magnetic aging and memory protocols and ac magnetic susceptibility. The dynamics of the system slow near 50 K, and become frozen on experimental time scales below 20 K. Remanence curves indicate the development of magnetic irreversibility concurrent with the freezing of the spin dynamics. A strong exchange-bias effect and its training behavior point to highly frustrated surface spins that rearrange much more slowly than interior spins. Monte Carlo simulations of a hollow particle corroborate strongly disordered surface layers with complex energy landscapes that underlie both glass-like dynamics and magnetic irreversibility. Calculated hysteresis loops reveal that magnetic behavior is not identical at the inner and outer surfaces, with spins at the outer surface layer of the 15 nm hollow particles exhibiting a higher degree of frustration. Our combined experimental and simulated results shed light on the origin of spin-glass-like phenomena and the important role played by the surface spins in magnetic hollow nanostructures.
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Niketic N, van den Brandt B, Wenckebach WT, Kohlbrecher J, Hautle P. Polarization analysis in neutron small-angle scattering with a novel triplet dynamic nuclear polarization spin filter. J Appl Crystallogr 2015. [DOI: 10.1107/s1600576715015575] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A novel neutron spin filter whose principle is based on the strong spin dependence of the neutron scattering on protons has been developed. The dimensions of this filter are small, and it works very efficiently and is stable even in inhomogeneous fields. The protons in the naphthalene spin filter crystal are polarized by a recently developed method of dynamic nuclear polarization using photoexcited triplet states. This technique allows the design of a very compact apparatus that can be placed at a close distance to the sample under investigation. The application of this filter as a polarization analyzer is demonstrated in a magnetic small-angle neutron scattering experiment with the measurement of the spin-dependent scattering signals of a CuFeNi alloy. This sample has a pronounced textured structure factor of ferromagnetic precipitates in a paramagnetic matrix. The performance of the spin filter as an analyzer is illustrated by the excellent agreement of the experimental data with simulations based on a model of homogeneously magnetized spherical particles which are ordered in a simple cubic paracrystalline lattice.
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Krycka KL, Borchers JA, Booth RA, Ijiri Y, Hasz K, Rhyne JJ, Majetich SA. Krycka et al. reply. PHYSICAL REVIEW LETTERS 2015; 114:149702. [PMID: 25910168 DOI: 10.1103/physrevlett.114.149702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Indexed: 06/04/2023]
Affiliation(s)
- K L Krycka
- 1NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
| | - J A Borchers
- 1NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
| | - R A Booth
- 2Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Y Ijiri
- 3Oberlin College, Oberlin, Ohio 44074, USA
| | - K Hasz
- 3Oberlin College, Oberlin, Ohio 44074, USA
| | - J J Rhyne
- 4U.S. Department of Energy, Washington, DC 20585, USA
| | - S A Majetich
- 2Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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Krycka KL, Borchers JA, Booth RA, Ijiri Y, Hasz K, Rhyne JJ, Majetich SA. Origin of surface canting within Fe3O4 nanoparticles. PHYSICAL REVIEW LETTERS 2014; 113:147203. [PMID: 25325655 DOI: 10.1103/physrevlett.113.147203] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Indexed: 05/27/2023]
Abstract
The nature of near-surface spin canting within Fe3O4 nanoparticles is highly debated. Here we develop a neutron scattering asymmetry analysis which quantifies the canting angle to between 23° and 42° at 1.2 T. Simultaneously, an energy-balance model is presented which reproduces the experimentally observed evolution of shell thickness and canting angle between 10 and 300 K. The model is based on the concept of Td site reorientation and indicates that surface canting involves competition between magnetocrystalline, dipolar, exchange, and Zeeman energies.
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Affiliation(s)
- K L Krycka
- NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
| | - J A Borchers
- NIST Center for Neutron Research, Gaithersburg, Maryland 20899, USA
| | - R A Booth
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Y Ijiri
- Oberlin College, Oberlin, Ohio 44074, USA
| | - K Hasz
- Oberlin College, Oberlin, Ohio 44074, USA
| | - J J Rhyne
- U.S. Department of Energy, Washington, D.C. 20585, USA
| | - S A Majetich
- Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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Michels A. Magnetic small-angle neutron scattering of bulk ferromagnets. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:383201. [PMID: 25180625 DOI: 10.1088/0953-8984/26/38/383201] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We summarize recent theoretical and experimental work in the field of magnetic small-angle neutron scattering (SANS) of bulk ferromagnets. The response of the magnetization to spatially inhomogeneous magnetic anisotropy and magnetostatic stray fields is computed using linearized micromagnetic theory, and the ensuing spin-misalignment SANS is deduced. Analysis of experimental magnetic-field-dependent SANS data of various nanocrystalline ferromagnets corroborates the usefulness of the approach, which provides important quantitative information on the magnetic-interaction parameters such as the exchange-stiffness constant, the mean magnetic anisotropy field, and the mean magnetostatic field due to jumps ΔM of the magnetization at internal interfaces. Besides the value of the applied magnetic field, it turns out to be the ratio of the magnetic anisotropy field Hp to ΔM, which determines the properties of the magnetic SANS cross-section of bulk ferromagnets; specifically, the angular anisotropy on a two-dimensional detector, the asymptotic power-law exponent, and the characteristic decay length of spin-misalignment fluctuations. For the two most often employed scattering geometries where the externally applied magnetic field H0 is either perpendicular or parallel to the wave vector k0 of the incoming neutron beam, we provide a compilation of the various unpolarized, half-polarized (SANSPOL), and uniaxial fully-polarized (POLARIS) SANS cross-sections of magnetic materials.
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Affiliation(s)
- Andreas Michels
- Physics and Materials Science Research Unit, University of Luxembourg, 162A Avenue de la Faïencerie, L-1511 Luxembourg, Grand Duchy of Luxembourg
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Chen WC, Gentile TR, Erwin R, Watson S, Ye Q, Krycka KL, Maranville BB. 3He spin filter based polarized neutron capability at the NIST Center for Neutron Research. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/1742-6596/528/1/012014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Dennis CL, Ivkov R. Physics of heat generation using magnetic nanoparticles for hyperthermia. Int J Hyperthermia 2013; 29:715-29. [PMID: 24131317 DOI: 10.3109/02656736.2013.836758] [Citation(s) in RCA: 166] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Magnetic nanoparticle hyperthermia and thermal ablation have been actively studied experimentally and theoretically. In this review, we provide a summary of the literature describing the properties of nanometer-scale magnetic materials suspended in biocompatible fluids and their interactions with external magnetic fields. Summarised are the properties and mechanisms understood to be responsible for magnetic heating, and the models developed to understand the behaviour of single-domain magnets exposed to alternating magnetic fields. Linear response theory and its assumptions have provided a useful beginning point; however, its limitations are apparent when nanoparticle heating is measured over a wide range of magnetic fields. Well-developed models (e.g. for magnetisation reversal mechanisms and pseudo-single domain formation) available from other fields of research are explored. Some of the methods described include effects of moment relaxation, anisotropy, nanoparticle and moment rotation mechanisms, interactions and collective behaviour, which have been experimentally identified to be important. Here, we will discuss the implicit assumptions underlying these analytical models and their relevance to experiments. Numerical simulations will be discussed as an alternative to these simple analytical models, including their applicability to experimental data. Finally, guidelines for the design of optimal magnetic nanoparticles will be presented.
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Affiliation(s)
- Cindi L Dennis
- Material Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg , Maryland and
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Faure B, Wetterskog E, Gunnarsson K, Josten E, Hermann RP, Brückel T, Andreasen JW, Meneau F, Meyer M, Lyubartsev A, Bergström L, Salazar-Alvarez G, Svedlindh P. 2D to 3D crossover of the magnetic properties in ordered arrays of iron oxide nanocrystals. NANOSCALE 2013; 5:953-960. [PMID: 23238262 DOI: 10.1039/c2nr33013j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The magnetic 2D to 3D crossover behavior of well-ordered arrays of monodomain γ-Fe(2)O(3) spherical nanoparticles with different thicknesses has been investigated by magnetometry and Monte Carlo (MC) simulations. Using the structural information of the arrays obtained from grazing incidence small-angle X-ray scattering and scanning electron microscopy together with the experimentally determined values for the saturation magnetization and magnetic anisotropy of the nanoparticles, we show that MC simulations can reproduce the thickness-dependent magnetic behavior. The magnetic dipolar particle interactions induce a ferromagnetic coupling that increases in strength with decreasing thickness of the array. The 2D to 3D transition in the magnetic properties is mainly driven by a change in the orientation of the magnetic vortex states with increasing thickness, becoming more isotropic as the thickness of the array increases. Magnetic anisotropy prevents long-range ferromagnetic order from being established at low temperature and the nanoparticle magnetic moments instead freeze along directions defined by the distribution of easy magnetization directions.
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Affiliation(s)
- Bertrand Faure
- Department of Material and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden
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Mao Z, Zhan X, Chen X. Defect-tuning exchange bias of ferromagnet/antiferromagnet core/shell nanoparticles by numerical study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:276002. [PMID: 22713516 DOI: 10.1088/0953-8984/24/27/276002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The influence of non-magnetic defects on the exchange bias (EB) of ferromagnet (FM)/antiferromagnet (AFM) core/shell nanoparticles is studied by Monte Carlo simulations. It is found that the EB can be tuned by defects in different positions. Defects at both the AFM and FM interfaces reduce the EB field while they enhance the coercive field by decreasing the effective interface coupling. However, the EB field and the coercive field show respectively a non-monotonic and a monotonic dependence on the defect concentration when the defects are located inside the AFM shell, indicating a similar microscopic mechanism to that proposed in the domain state model. These results suggest a way to optimize the EB effect for applications.
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Affiliation(s)
- Zhongquan Mao
- Department of Physics, South China University of Technology, Guangzhou 510640, People's Republic of China
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de Montferrand C, Lalatonne Y, Bonnin D, Lièvre N, Lecouvey M, Monod P, Russier V, Motte L. Size-dependent nonlinear weak-field magnetic behavior of maghemite nanoparticles. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2012; 8:1945-1956. [PMID: 22488765 DOI: 10.1002/smll.201102660] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 01/30/2012] [Indexed: 05/31/2023]
Abstract
The magnetic behavior at room temperature of maghemite nanoparticles of variable sizes (from 7 to 20 nm) is compared using a conventional super quantum interference device (SQUID) and a recently patented technology, called MIAplex. The SQUID usually measures the magnetic response versus an applied magnetic field in a quasi-static mode until high field values (from -4000 to 4000 kA m(-1)) to determine the field-dependence and saturation magnetization of the sample. The MIAplex is a handheld portable device that measures a signal corresponding to the second derivative of the magnetization around zero field (between -15 and 15 kA m(-1)). In this paper, the magnetic response of the size series is correlated, both in diluted and powder form, between the SQUID and MIAplex. The SQUID curves are measured at room temperature in two magnetic field ranges from -4000 to 4000 kA m(-1) (-5T to 5T) and from -15 to 15 kA m(-1). Nonlinear behavior at weak fields is highlighted and the magnetic curves for diluted solutions evolve from quasi-paramagnetic to superparamagnetic behavior when the size of the nanoparticles increases. For the 7-nm sample, the fit of the magnetization with the Langevin model weighted with log-normal distribution corresponds closely to the magnetic size. This confirms the accuracy of the model of non-interacting superparamagnetic particles with a magnetically frustrated surface layer of about 0.5 nm thickness. For the other samples (10-nm to 21-nm), the experimental weak-field magnetization curves are modeled by more than one population of magnetically responding species. This behavior is consistent with a chemically uniform but magnetically distinct structure composed of a core and a magnetically active nanoparticle canted shell. Accordingly the weak-field signature corresponds to the total assembly of the nanoparticles. The impact of size polydispersity is also discussed.
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Das S, Majumdar S, Giri S. Multifunctional properties of CoNi alloy embedded in the SiO2 host: Role of interparticle interaction. J SOLID STATE CHEM 2011. [DOI: 10.1016/j.jssc.2011.06.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Amstad E, Textor M, Reimhult E. Stabilization and functionalization of iron oxide nanoparticles for biomedical applications. NANOSCALE 2011; 3:2819-43. [PMID: 21629911 DOI: 10.1039/c1nr10173k] [Citation(s) in RCA: 237] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Superparamagnetic iron oxide nanoparticles (NPs) are used in a rapidly expanding number of research and practical applications in the biomedical field, including magnetic cell labeling separation and tracking, for therapeutic purposes in hyperthermia and drug delivery, and for diagnostic purposes, e.g., as contrast agents for magnetic resonance imaging. These applications require good NP stability at physiological conditions, close control over NP size and controlled surface presentation of functionalities. This review is focused on different aspects of the stability of superparamagnetic iron oxide NPs, from its practical definition to its implementation by molecular design of the dispersant shell around the iron oxide core and further on to its influence on the magnetic properties of the superparamagnetic iron oxide NPs. Special attention is given to the selection of molecular anchors for the dispersant shell, because of their importance to ensure colloidal and functional stability of sterically stabilized superparamagnetic iron oxide NPs. We further detail how dispersants have been optimized to gain close control over iron oxide NP stability, size and functionalities by independently considering the influences of anchors and the attached sterically repulsive polymer brushes. A critical evaluation of different strategies to stabilize and functionalize core-shell superparamagnetic iron oxide NPs as well as a brief introduction to characterization methods to compare those strategies is given.
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Affiliation(s)
- Esther Amstad
- Laboratory for Surface Science and Technology, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland
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Chen WC, Gentile TR, Fu CB, Watson S, Jones GL, McIver JW, Rich DR. Polarized3He cell development and application at NIST. ACTA ACUST UNITED AC 2011. [DOI: 10.1088/1742-6596/294/1/012003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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41
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Honecker D, Döbrich F, Dewhurst CD, Wiedenmann A, Michels A. Neutron spin-flip scattering of nanocrystalline cobalt. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:016003. [PMID: 21406833 DOI: 10.1088/0953-8984/23/1/016003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report results of longitudinal (one-dimensional) neutron polarization analysis on polycrystalline bulk Co with an average crystallite size of D = 10 nm. The spin-flip small-angle neutron scattering (SANS) data are analyzed in the approach-to-saturation regime within the framework of micromagnetic theory. In particular, we provide a closed-form expression for the spin-flip SANS cross section [Formula: see text]. From the data analysis, we find a room-temperature value of A = (2.6 ± 0.1) × 10( - 11) J m( - 1) for the exchange-stiffness constant, which agrees well with earlier data.
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Affiliation(s)
- D Honecker
- Laboratory for the Physics of Advanced Materials, University of Luxembourg, 162A Avenue de la Faïencerie, L-1511 Luxembourg, Luxembourg
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Nanoscience: Shifted shells. Nature 2010. [DOI: 10.1038/465529a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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