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Poryvai A, Šmahel M, Švecová M, Nemati A, Shadpour S, Ulbrich P, Ogolla T, Liu J, Novotná V, Veverka M, Vejpravová J, Hegmann T, Kohout M. Chiral, Magnetic, and Photosensitive Liquid Crystalline Nanocomposites Based on Multifunctional Nanoparticles and Achiral Liquid Crystals. ACS NANO 2022; 16:11833-11841. [PMID: 35867644 DOI: 10.1021/acsnano.1c10594] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nanoparticles serving as a multifunctional and multiaddressable dopant to modify the properties of liquid crystalline matrices are developed by combining cobalt ferrite nanocrystals with organic ligands featuring a robust photosensitive unit and a source of chirality from the natural pool. These nanoparticles provide a stable nanocomposite when dispersed in achiral liquid crystals, giving rise to chiral supramolecular structures that can respond to UV-light illumination, and, at the same time, the formed nanocomposite possesses strong magnetic response. We report on a nanocomposite that shows three additional functionalities (chirality and responsiveness to UV light and magnetic field) upon the introduction of a single dopant into achiral liquid crystals.
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Affiliation(s)
- Anna Poryvai
- Department of Organic Chemistry, University of Chemistry and Technology Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Michal Šmahel
- Department of Organic Chemistry, University of Chemistry and Technology Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Marie Švecová
- Department of Analytical Chemistry, University of Chemistry and Technology Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Ahlam Nemati
- Materials Science Graduate Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Sasan Shadpour
- Materials Science Graduate Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Pavel Ulbrich
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 3, 16628 Prague 6, Czech Republic
| | - Timothy Ogolla
- Materials Science Graduate Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Jiao Liu
- Materials Science Graduate Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Vladimíra Novotná
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - Miroslav Veverka
- Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - Jana Vejpravová
- Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - Torsten Hegmann
- Materials Science Graduate Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
- Brain Health Research Institute, Kent State University, Kent, Ohio 44242-0001, United States
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242-0001, United States
| | - Michal Kohout
- Department of Organic Chemistry, University of Chemistry and Technology Prague, Technická 5, 16628 Prague 6, Czech Republic
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2
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Fan X, Walther A. 1D Colloidal chains: recent progress from formation to emergent properties and applications. Chem Soc Rev 2022; 51:4023-4074. [PMID: 35502721 DOI: 10.1039/d2cs00112h] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Integrating nanoscale building blocks of low dimensionality (0D; i.e., spheres) into higher dimensional structures endows them and their corresponding materials with emergent properties non-existent or only weakly existent in the individual building blocks. Constructing 1D chains, 2D arrays and 3D superlattices using nanoparticles and colloids therefore continues to be one of the grand goals in colloid and nanomaterial science. Amongst these higher order structures, 1D colloidal chains are of particular interest, as they possess unique anisotropic properties. In recent years, the most relevant advances in 1D colloidal chain research have been made in novel synthetic methodologies and applications. In this review, we first address a comprehensive description of the research progress concerning various synthetic strategies developed to construct 1D colloidal chains. Following this, we highlight the amplified and emergent properties of the resulting materials, originating from the assembly of the individual building blocks and their collective behavior, and discuss relevant applications in advanced materials. In the discussion of synthetic strategies, properties, and applications, particular attention will be paid to overarching concepts, fresh trends, and potential areas of future research. We believe that this comprehensive review will be a driver to guide the interdisciplinary field of 1D colloidal chains, where nanomaterial synthesis, self-assembly, physical property studies, and material applications meet, to a higher level, and open up new research opportunities at the interface of classical disciplines.
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Affiliation(s)
- Xinlong Fan
- Institute for Macromolecular Chemistry, Albert-Ludwigs-University Freiburg, Stefan-Meier-Str. 31, 79104, Freiburg, Germany.
| | - Andreas Walther
- A3BMS Lab, Department of Chemistry, University of Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
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Kralj S, Marchesan S. Bioinspired Magnetic Nanochains for Medicine. Pharmaceutics 2021; 13:1262. [PMID: 34452223 PMCID: PMC8398308 DOI: 10.3390/pharmaceutics13081262] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 12/12/2022] Open
Abstract
Superparamagnetic iron oxide nanoparticles (SPIONs) have been widely used for medicine, both in therapy and diagnosis. Their guided assembly into anisotropic structures, such as nanochains, has recently opened new research avenues; for instance, targeted drug delivery. Interestingly, magnetic nanochains do occur in nature, and they are thought to be involved in the navigation and geographic orientation of a variety of animals and bacteria, although many open questions on their formation and functioning remain. In this review, we will analyze what is known about the natural formation of magnetic nanochains, as well as the synthetic protocols to produce them in the laboratory, to conclude with an overview of medical applications and an outlook on future opportunities in this exciting research field.
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Affiliation(s)
- Slavko Kralj
- Department for Materials Synthesis, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Silvia Marchesan
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, 34127 Trieste, Italy;
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Nandakumaran N, Barnsley L, Feoktystov A, Ivanov SA, Huber DL, Fruhner LS, Leffler V, Ehlert S, Kentzinger E, Qdemat A, Bhatnagar-Schöffmann T, Rücker U, Wharmby MT, Cervellino A, Dunin-Borkowski RE, Brückel T, Feygenson M. Unravelling Magnetic Nanochain Formation in Dispersion for In Vivo Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008683. [PMID: 33960040 DOI: 10.1002/adma.202008683] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/25/2021] [Indexed: 05/27/2023]
Abstract
Self-assembly of iron oxide nanoparticles (IONPs) into 1D chains is appealing, because of their biocompatibility and higher mobility compared to 2D/3D assemblies while traversing the circulatory passages and blood vessels for in vivo biomedical applications. In this work, parameters such as size, concentration, composition, and magnetic field, responsible for chain formation of IONPs in a dispersion as opposed to spatially confining substrates, are examined. In particular, the monodisperse 27 nm IONPs synthesized by an extended LaMer mechanism are shown to form chains at 4 mT, which are lengthened with applied field reaching 270 nm at 2.2 T. The chain lengths are completely reversible in field. Using a combination of scattering methods and reverse Monte Carlo simulations the formation of chains is directly visualized. The visualization of real-space IONPs assemblies formed in dispersions presents a novel tool for biomedical researchers. This allows for rapid exploration of the behavior of IONPs in solution in a broad parameter space and unambiguous extraction of the parameters of the equilibrium structures. Additionally, it can be extended to study novel assemblies formed by more complex geometries of IONPs.
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Affiliation(s)
- Nileena Nandakumaran
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, 52425, Jülich, Germany
- Lehrstuhl für Experimentalphysik IVc, RWTH Aachen University, 52056, Aachen, Germany
| | - Lester Barnsley
- Australian Synchrotron, ANSTO, Clayton, 3168, Australia
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85748, Garching, Germany
| | - Artem Feoktystov
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85748, Garching, Germany
| | - Sergei A Ivanov
- Materials Physics and Applications Division: Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Dale L Huber
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, 87123, USA
| | - Lisa S Fruhner
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056, Aachen, Germany
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Biological Matter (IBI-8), 52425, Jülich, Germany
| | - Vanessa Leffler
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056, Aachen, Germany
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Biological Matter (IBI-8), 52425, Jülich, Germany
| | - Sascha Ehlert
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Biological Matter (IBI-8), 52425, Jülich, Germany
| | - Emmanuel Kentzinger
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, 52425, Jülich, Germany
| | - Asma Qdemat
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, 52425, Jülich, Germany
- Lehrstuhl für Experimentalphysik IVc, RWTH Aachen University, 52056, Aachen, Germany
| | - Tanvi Bhatnagar-Schöffmann
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, 52425, Jülich, Germany
- Lehrstuhl für Experimentalphysik IVc, RWTH Aachen University, 52056, Aachen, Germany
- Forschungszentrum Jülich GmbH, Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, 52425, Jülich, Germany
| | - Ulrich Rücker
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, 52425, Jülich, Germany
| | - Michael T Wharmby
- PETRA III, Deutsches Elektronen-Synchrotron DESY, 22607, Hamburg, Germany
| | - Antonio Cervellino
- Swiss Light Source, Paul-Scherrer-Institut, Villigen PSI, 5232, Switzerland
| | - Rafal E Dunin-Borkowski
- Forschungszentrum Jülich GmbH, Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, 52425, Jülich, Germany
| | - Thomas Brückel
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, 52425, Jülich, Germany
- Lehrstuhl für Experimentalphysik IVc, RWTH Aachen University, 52056, Aachen, Germany
| | - Mikhail Feygenson
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1) and Biological Matter (IBI-8), 52425, Jülich, Germany
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5
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Mati IK, Edwards W, Marson D, Howe EJ, Stinson S, Posocco P, Kay ER. Probing Multiscale Factors Affecting the Reactivity of Nanoparticle-Bound Molecules. ACS NANO 2021; 15:8295-8305. [PMID: 33938222 DOI: 10.1021/acsnano.0c09190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The structures and physicochemical properties of surface-stabilizing molecules play a critical role in defining the properties, interactions, and functionality of hybrid nanomaterials such as monolayer-stabilized nanoparticles. Concurrently, the distinct surface-bound interfacial environment imposes very specific conditions on molecular reactivity and behavior in this setting. Our ability to probe hybrid nanoscale systems experimentally remains limited, yet understanding the consequences of surface confinement on molecular reactivity is crucial for enabling predictive nanoparticle synthon approaches for postsynthesis engineering of nanoparticle surface chemistry and construction of devices and materials from nanoparticle components. Here, we have undertaken an integrated experimental and computational study of the reaction kinetics for nanoparticle-bound hydrazones, which provide a prototypical platform for understanding chemical reactivity in a nanoconfined setting. Systematic variation of just one molecular-scale structural parameter-the distance between reactive site and nanoparticle surface-showed that the surface-bound reactivity is influenced by multiscale effects. Nanoparticle-bound reactions were tracked in situ using 19F NMR spectroscopy, allowing direct comparison to the reactions of analogous substrates in bulk solution. The surface-confined reactions proceed more slowly than their solution-phase counterparts, and kinetic inhibition becomes more significant for reactive sites positioned closer to the nanoparticle surface. Molecular dynamics simulations allowed us to identify distinct supramolecular architectures and unexpected dynamic features of the surface-bound molecules that underpin the experimentally observed trends in reactivity. This study allows us to draw general conclusions regarding interlinked structural and dynamical features across several length scales that influence interfacial reactivity in monolayer-confined environments.
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Affiliation(s)
- Ioulia K Mati
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, U.K
| | - William Edwards
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, U.K
| | - Domenico Marson
- Department of Engineering and Architecture, University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy
| | - Edward J Howe
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, U.K
| | - Scott Stinson
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, U.K
| | - Paola Posocco
- Department of Engineering and Architecture, University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy
| | - Euan R Kay
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, KY16 9ST, U.K
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Aurélio D, Mikšátko J, Veverka M, Michlová M, Kalbáč M, Vejpravová J. Thermal Traits of MNPs under High-Frequency Magnetic Fields: Disentangling the Effect of Size and Coating. NANOMATERIALS 2021; 11:nano11030797. [PMID: 33808938 PMCID: PMC8003606 DOI: 10.3390/nano11030797] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/14/2021] [Accepted: 03/17/2021] [Indexed: 12/23/2022]
Abstract
We investigated the heating abilities of magnetic nanoparticles (MNPs) in a high-frequency magnetic field (MF) as a function of surface coating and size. The cobalt ferrite MNPs were obtained by a hydrothermal method in a water–oleic acid–ethanol system, yielding MNPs with mean diameter of about 5 nm, functionalized with the oleic acid. By applying another cycle of hydrothermal synthesis, we obtained MNPs with about one nm larger diameter. In the next step, the oleic acid was exchanged for 11-maleimidoundecanoic acid or 11-(furfurylureido)undecanoic acid. For the heating experiments, all samples were dispersed in the same solvent (dichloroethane) in the same concentration and the heating performance was studied in a broad interval of MF frequencies (346–782 kHz). The obtained results enabled us to disentangle the impact of the hydrodynamic, structural, and magnetic parameters on the overall heating capabilities. We also demonstrated that the specific power absorption does not show a monotonous trend within the series in the investigated interval of temperatures, pointing to temperature-dependent competition of the Brownian and Néel contributions in heat release.
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Affiliation(s)
- David Aurélio
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic;
- Correspondence: (D.A.); (J.V.)
| | - Jiří Mikšátko
- J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, v.v.i., Dolejškova 2155/3, 182 23 Prague 8, Czech Republic; (J.M.); (M.M.); (M.K.)
| | - Miroslav Veverka
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic;
| | - Magdalena Michlová
- J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, v.v.i., Dolejškova 2155/3, 182 23 Prague 8, Czech Republic; (J.M.); (M.M.); (M.K.)
| | - Martin Kalbáč
- J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, v.v.i., Dolejškova 2155/3, 182 23 Prague 8, Czech Republic; (J.M.); (M.M.); (M.K.)
| | - Jana Vejpravová
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic;
- Correspondence: (D.A.); (J.V.)
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7
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Liu Y, Chen F, Guo D, Ma Y. One-dimensional assembly of β-form anhydrous guanine microrods. SOFT MATTER 2021; 17:1955-1962. [PMID: 33427846 DOI: 10.1039/d0sm01717e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Biogenic guanine crystals exhibit excellent optical properties owing to their extremely high refractive index. However, there is no report related to the highly-ordered guanine assemblies in the synthetic systems. Herein, β-phase anhydrous guanine (β-AG) microrods were formed in mixed solvents of formamide and water in the presence of small organic molecules such as uric acid, pyrrole (Py), N-methyl-2-pyrrolidone (NMP), N-vinyl-2-pyrrolidone (NVP). The one-dimensional (1D) assembly of β-AG microrods form spontaneously in water, which is the first reported highly ordered 1D assembly of organic micro- or nanocrystals in the solution. The obtained β-AG microrods obtained in Py system can form reversible 1D assembly in water after being treated in organic solvents such as ethanol, acetone and isopropanol, which have high solubility in water. However, no reversible 1D assembly but only dispersed or aggregated guanine microrods formed in water after similar treatment in the other three organic solvents such as n-hexane, dichloroethane and petroleum ether with low solubility in water. Similar reversible assembly features can also be observed in other three systems, standard system, and NVP and NMP systems. The reversible 1D assemblies of guanine microrods in water and organic solvents with high solubility in water indicate that there is a strong interaction between the (100) planes of β-AG microrods in water. The oriented 1D assembly of guanine microrods with long axes perpendicular to the horizontal magnetic field can form in water under magnetic field.
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Affiliation(s)
- Yanan Liu
- MOE Key laboratory of Cluster Science, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Fenghua Chen
- MOE Key laboratory of Cluster Science, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China. and School of Resources and Chemical Engineering, Sanming University, Jingdong Road 25, Sanming, 365004, China
| | - Dongmei Guo
- MOE Key laboratory of Cluster Science, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Yurong Ma
- MOE Key laboratory of Cluster Science, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
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8
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Barrera G, Allia P, Tiberto P. Fine tuning and optimization of magnetic hyperthermia treatments using versatile trapezoidal driving-field waveforms. NANOSCALE ADVANCES 2020; 2:4652-4664. [PMID: 36132915 PMCID: PMC9417573 DOI: 10.1039/d0na00358a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/27/2020] [Indexed: 06/12/2023]
Abstract
Applying trapezoidal driving-field waveforms to activate magnetic nanoparticles optimizes their performance as heat generators in magnetic hyperthermia, with notable advantages with respect to the effects of harmonic magnetic fields of the same frequency and amplitude. A rate equation approach is used to determine the hysteretic properties and the power released by monodisperse and polydisperse magnetite nanoparticles with randomly oriented easy axes subjected to a radio-frequency trapezoidal driving field. The heating ability of the activated nanoparticles is investigated by means of a simple model in which the heat equation is solved in radial geometry with boundary conditions simulating in vivo applications. Changes of the inclination of the trapezoidal waveform's lateral sides are shown to induce controlled changes in the specific loss power generated by the activated nanoparticles. Specific issues typical of the therapeutic practice of hyperthermia, such as the need for fine tuning of the optimal treatment temperature in real time, the possibility of combining sequential treatments at different temperatures, and the ability to substantially reduce the heating transient in a hyperthermia treatment are suitably addressed and overcome by making use of versatile driving fields of a trapezoidal shape.
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Affiliation(s)
- Gabriele Barrera
- INRIM, Advanced Materials Metrology and Life Sciences Strada delle Cacce 91 I-10135 Torino Italy +39 011 3919858
| | - Paolo Allia
- INRIM, Advanced Materials Metrology and Life Sciences Strada delle Cacce 91 I-10135 Torino Italy +39 011 3919858
| | - Paola Tiberto
- INRIM, Advanced Materials Metrology and Life Sciences Strada delle Cacce 91 I-10135 Torino Italy +39 011 3919858
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Hu T, Ji Q, Chong WH, Xin W, Liu X, Chen H. On the effect of Fe oleate by-product in nano-stirbar synthesis. NANOSCALE 2020; 12:18640-18645. [PMID: 32914823 DOI: 10.1039/d0nr04453a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We show that the by-product obtained from the preparation of Fe3O4 nanoparticles has dramatic effects on the synthesis of nano-stirbars. It is an oily substance likely resulting from the polymerization of oleic acid, followed by coordination/crosslinking with Fe ions. As such it is extremely difficult to remove it by conventional methods. By combining nonpolar organic solvent, prolonged swelling, and low-speed centrifugation, the by-product is successfully removed. Thus, various magnetic nanoparticles could be used for synthesizing nano-stirbars. Among them, the smallest nano-stirbars have reached a width of 21 nm and a length of ∼350 nm, setting a record. The nano-stirbars could be directly driven using a common hotplate stirrer, to facilitate mixing in tiny spaces.
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Affiliation(s)
- Ting Hu
- Institute of Advanced Synthesis (IAS), and School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Centre for Advanced Materials, Nanjing Tech University, Nanjing 211816, P. R. China.
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10
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Understanding Magnetization Dynamics of a Magnetic Nanoparticle with a Disordered Shell Using Micromagnetic Simulations. NANOMATERIALS 2020; 10:nano10061149. [PMID: 32545385 PMCID: PMC7353241 DOI: 10.3390/nano10061149] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/30/2020] [Accepted: 06/05/2020] [Indexed: 11/17/2022]
Abstract
Spin disorder effects influence magnetization dynamics and equilibrium magnetic properties of real nanoparticles (NPs). In this work, we use micromagnetic simulations to try to better understand these effects, in particular, on how the magnetization reversal is projected in the character of the hysteresis loops at different temperatures. In our simulation study, we consider a prototype NP adopting a magnetic core-shell model, with magnetically coherent core and somewhat disordered shell, as it is one of the common spin architectures in real NPs. The size of the core is fixed to 5.5 nm in diameter and the shell thickness ranges from 0.5 nm to 3 nm. As a starting point in the simulations, we used typical experimental values obtained for a cobalt ferrite NP of a comparable size investigated previously. The simulations enabled us to study systematically the macrospin dynamics of the prototype NP and to address the interplay between the magnetic anisotropies of the core and the shell, respectively. We also demonstrate how the computational time step, run time, damping parameter, and thermal field influence the simulation results. In agreement with experimental studies, we observed that the direction and magnitude of the shell anisotropy influences the effective magnetic size of the core in the applied magnetic field. We conclude that micromagnetic simulations, in spite of being designed for much larger scales are a useful toolbox for understanding the magnetization processes within a single domain NP with an ordered spin structure in the core and partially disordered spins in the shell.
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11
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Marro N, Della Sala F, Kay ER. Programmable dynamic covalent nanoparticle building blocks with complementary reactivity. Chem Sci 2019; 11:372-383. [PMID: 32190260 PMCID: PMC7067244 DOI: 10.1039/c9sc04195h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 11/14/2019] [Indexed: 12/28/2022] Open
Abstract
A toolkit of two complementary dynamic covalent nanoparticles enables programmable and reversible nanoparticle functionalization and construction of adaptive binary assemblies.
Nanoparticle-based devices, materials and technologies will demand a new era of synthetic chemistry where predictive principles familiar in the molecular regime are extended to nanoscale building blocks. Typical covalent strategies for modifying nanoparticle-bound species rely on kinetically controlled reactions optimised for efficiency but with limited capacity for selective and divergent access to a range of product constitutions. In this work, monolayer-stabilized nanoparticles displaying complementary dynamic covalent hydrazone exchange reactivity undergo distinct chemospecific transformations by selecting appropriate combinations of ‘nucleophilic’ or ‘electrophilic’ nanoparticle-bound monolayers with nucleophilic or electrophilic molecular modifiers. Thermodynamically governed reactions allow modulation of product compositions, spanning mixed-ligand monolayers to exhaustive exchange. High-density nanoparticle-stabilizing monolayers facilitate in situ reaction monitoring by quantitative 19F NMR spectroscopy. Kinetic analysis reveals that hydrazone exchange rates are moderately diminished by surface confinement, and that the magnitude of this effect is dependent on mechanistic details: surface-bound electrophiles react intrinsically faster, but are more significantly affected by surface immobilization than nucleophiles. Complementary nanoparticles react with each other to form robust covalently connected binary aggregates. Endowed with the adaptive characteristics of the dynamic covalent linking process, the nanoscale assemblies can be tuned from extended aggregates to colloidally stable clusters of equilibrium sizes that depend on the concentration of a monofunctional capping agent. Just two ‘dynamic covalent nanoparticles’ with complementary thermodynamically governed reactivities therefore institute a programmable toolkit offering flexible control over nanoparticle surface functionalization, and construction of adaptive assemblies that selectively combine several nanoscale building blocks.
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Affiliation(s)
- Nicolas Marro
- EaStCHEM School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
| | - Flavio Della Sala
- EaStCHEM School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
| | - Euan R Kay
- EaStCHEM School of Chemistry , University of St Andrews , North Haugh , St Andrews , KY16 9ST , UK .
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