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Mahendravada S, Lahiri BB, Khan F, Sathyanarayana AT, Vizhi RE, Moorthy A, Philip J. A nudge over the relaxation plateau: effect of pH, particle concentration, and medium viscosity on the AC induction heating efficiency of biocompatible chitosan-coated Fe 3O 4nanoparticles. Nanotechnology 2024; 35:165704. [PMID: 38211331 DOI: 10.1088/1361-6528/ad1d79] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 01/11/2024] [Indexed: 01/13/2024]
Abstract
The effects of pH, MNP concentration, and medium viscosity on the magnetic fluid hyperthermia (MFH) properties of chitosan-coated superparamagnetic Fe3O4nanoparticles (MNPs) are probed here. Due to the protonation of the amide groups, the MNPs are colloidally stable at lower pH (∼2), but form aggregates at higher pH (∼8). The increased aggregate size at higher pH causes the Brownian relaxation time (τB) to increase, leading to a decrease in specific absorption rate (SAR). For colloidal conditions ensuring Brownian-dominated relaxation dynamics, an increase in MNP concentrations or medium viscosity is found to increase theτB. SAR decreases with increasing MNP concentration, whereas it exhibits a non-monotonic variation with increasing medium viscosity. Dynamic hysteresis loop-based calculations are found to be in agreement with the experimental results. The findings provide a greater understanding of the variation of SAR with the colloidal properties and show the importance of relaxation dynamics on MFH efficiency, where variations in the frequency-relaxation time product across the relaxation plateau cause significant variations in SAR. Further, thein vitrocytotoxicity studies show good bio-compatibility of the chitosan-coated Fe3O4MNPs. Higher SAR at acidic pH for bio-medically acceptable field parameters makes the bio-compatible chitosan-coated Fe3O4MNPs suitable for MFH applications.
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Affiliation(s)
- Srujana Mahendravada
- Smart Materials Section, Materials Characterization Group (MCG), Metallurgy and Materials Group (MMG), Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamil Nadu, PIN 603102, India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai, PIN 400094, India
| | - B B Lahiri
- Smart Materials Section, Materials Characterization Group (MCG), Metallurgy and Materials Group (MMG), Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamil Nadu, PIN 603102, India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai, PIN 400094, India
| | - Fouzia Khan
- Smart Materials Section, Materials Characterization Group (MCG), Metallurgy and Materials Group (MMG), Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamil Nadu, PIN 603102, India
| | - A T Sathyanarayana
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai, PIN 400094, India
- Low Temperature Studies Section, Condensed Matter Physics Division, Materials Science Group, IGCAR, Tamil Nadu, PIN 603102, India
| | - R Ezhil Vizhi
- Materials Research Laboratory, Centre for Functional Materials, Vellore Institute of Technology, Vellore, Tamil Nadu, PIN 632014, India
| | - Anbalagan Moorthy
- Department of Integrative Biology, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, PIN 632014, India
| | - John Philip
- Smart Materials Section, Materials Characterization Group (MCG), Metallurgy and Materials Group (MMG), Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamil Nadu, PIN 603102, India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai, PIN 400094, India
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2
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Phukan G, Kar M, Borah JP. Interplay of Anisotropy Energy Barrier and Self-Heating Efficiency of Cobalt-Substituted CuFe 2O 4 Nanoparticles. ACS Appl Mater Interfaces 2024; 16:261-271. [PMID: 38118053 DOI: 10.1021/acsami.3c14594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
In this study, we delve into the intricate interplay between the anisotropy energy barrier and the self-heating efficiency of magnetic nanoparticles (MNPs). We embarked on this exploration by synthesizing Cu1-xCoxFe2O4 (x = 0, 0.1, 0.3, and 0.5) MNPs using a straightforward coprecipitation method. Our magnetic assessments, conducted at different temperatures, unveiled a notable trend as we traversed from x = 0.1 to x = 0.5. Specifically, we observed a consistent increase in saturation magnetization, coercivity, and remanence. This pattern also extended to the anisotropy energy barrier, which was derived from the effective anisotropy constant determined through the temperature dependency of the coercivity method. However, an intriguing twist emerged when we scrutinized the specific absorption rate (SAR), calculated via the Box-Lucas method. Contrary to much of the existing literature, our experimental results showcased a decline in SAR concerning x. This experimental work challenges the conventional understanding of the relationship between the anisotropy energy barrier and the SAR value of these nanoparticles. This study prompts us to reconsider the intricate mechanisms governing the relaxation of magnetic moments and subsequent heat release when subjected to an alternating magnetic field. By doing so, we aim to gain fresh insights into the self-heating properties of MNPs and optimize their utilization to better understand their heat-release properties and ensure that they are used as efficiently as possible in a variety of biomedical applications.
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Affiliation(s)
- Gongotree Phukan
- Nanomagnetism Lab, Department of Physics, National Institute of Technology Nagaland, Chumukedima, Nagaland 797103, India
| | - Manoranjan Kar
- Department of Physics, Indian Institute of Technology Patna, Bihar 800013, India
| | - J P Borah
- Nanomagnetism Lab, Department of Physics, National Institute of Technology Nagaland, Chumukedima, Nagaland 797103, India
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3
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Riske KA, González Miera G, Walker GC. Virtual Issue: Interfacial Science Developments in Latin America. Langmuir 2023; 39:18673-18677. [PMID: 38146262 DOI: 10.1021/acs.langmuir.3c03761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
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4
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Ilg P, Kröger M. Field- and concentration-dependent relaxation of magnetic nanoparticles and optimality conditions for magnetic fluid hyperthermia. Sci Rep 2023; 13:16523. [PMID: 37783724 PMCID: PMC10545801 DOI: 10.1038/s41598-023-43140-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 09/20/2023] [Indexed: 10/04/2023] Open
Abstract
The field-dependent relaxation dynamics of suspended magnetic nanoparticles continues to present a fascinating topic of basic science that at the same time is highly relevant for several technological and biomedical applications. Renewed interest in the intriguing behavior of magnetic nanoparticles in response to external fields has at least in parts be driven by rapid advances in magnetic fluid hyperthermia research. Although a wealth of experimental, theoretical, and simulation studies have been performed in this field in recent years, several contradictory findings have so far prevented the emergence of a consistent picture. Here, we present a dynamic mean-field theory together with comprehensive computer simulations of a microscopic model system to systematically discuss the influence of several key parameters on the relaxation dynamics, such as steric and dipolar interactions, the external magnetic field strength and frequency, as well as the ratio of Brownian and Néel relaxation time. We also discuss the specific and intrinsic loss power as measures of the efficiency of magnetic fluid heating and discuss optimality conditions in terms of fluid and field parameters. Our results are helpful to reconcile contradictory findings in the literature and provide an important step towards a more consistent understanding. In addition, our findings also help to select experimental conditions that optimize magnetic fluid heating applications.
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Affiliation(s)
- Patrick Ilg
- School of Mathematical, Physical, and Computational Sciences, University of Reading, Reading, RG6 6AX, UK.
| | - Martin Kröger
- Magnetism and Interface Physics, Computational Polymer Physics, Department of Materials, ETH Zurich, 8093, Zurich, Switzerland
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5
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Vargas-ortiz JR, Gonzalez C, Esquivel K. Magnetic Iron Nanoparticles: Synthesis, Surface Enhancements, and Biological Challenges. Processes (Basel) 2022; 10:2282. [DOI: 10.3390/pr10112282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This review focuses on the role of magnetic nanoparticles (MNPs), their physicochemical properties, their potential applications, and their association with the consequent toxicological effects in complex biologic systems. These MNPs have generated an accelerated development and research movement in the last two decades. They are solving a large portion of problems in several industries, including cosmetics, pharmaceuticals, diagnostics, water remediation, photoelectronics, and information storage, to name a few. As a result, more MNPs are put into contact with biological organisms, including humans, via interacting with their cellular structures. This situation will require a deeper understanding of these particles’ full impact in interacting with complex biological systems, and even though extensive studies have been carried out on different biological systems discussing toxicology aspects of MNP systems used in biomedical applications, they give mixed and inconclusive results. Chemical agencies, such as the Registration, Evaluation, Authorization, and Restriction of Chemical substances (REACH) legislation for registration, evaluation, and authorization of substances and materials from the European Chemical Agency (ECHA), have held meetings to discuss the issue. However, nanomaterials (NMs) are being categorized by composition alone, ignoring the physicochemical properties and possible risks that their size, stability, crystallinity, and morphology could bring to health. Although several initiatives are being discussed around the world for the correct management and disposal of these materials, thanks to the extensive work of researchers everywhere addressing the issue of related biological impacts and concerns, and a new nanoethics and nanosafety branch to help clarify and bring together information about the impact of nanoparticles, more questions than answers have arisen regarding the behavior of MNPs with a wide range of effects in the same tissue. The generation of a consolidative framework of these biological behaviors is necessary to allow future applications to be manageable.
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6
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Comanescu C. Magnetic Nanoparticles: Current Advances in Nanomedicine, Drug Delivery and MRI. Chemistry 2022; 4:872-930. [DOI: 10.3390/chemistry4030063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Magnetic nanoparticles (MNPs) have evolved tremendously during recent years, in part due to the rapid expansion of nanotechnology and to their active magnetic core with a high surface-to-volume ratio, while their surface functionalization opened the door to a plethora of drug, gene and bioactive molecule immobilization. Taming the high reactivity of the magnetic core was achieved by various functionalization techniques, producing MNPs tailored for the diagnosis and treatment of cardiovascular or neurological disease, tumors and cancer. Superparamagnetic iron oxide nanoparticles (SPIONs) are established at the core of drug-delivery systems and could act as efficient agents for MFH (magnetic fluid hyperthermia). Depending on the functionalization molecule and intrinsic morphological features, MNPs now cover a broad scope which the current review aims to overview. Considering the exponential expansion of the field, the current review will be limited to roughly the past three years.
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Myrovali E. Hybrid Stents Based on Magnetic Hydrogels for Biomedical Applications. ACS Appl Bio Mater 2022; 5:2598-2607. [PMID: 35580307 DOI: 10.1021/acsabm.2c00088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tremendous attention has been given to hydrogels due to their mechanical and physical properties. Hydrogels are promising biomaterials due to their high biocompatibility. Magnetic hydrogels, which are based on hydrogel incorporated magnetic nanoparticles, have been proposed in biomedical applications. The advantages of magnetic hydrogels are that they can easily respond to externally applied magnetic fields and prevent the leakage of magnetic nanoparticles in the surrounding area. Herein, a prototype hybrid stent of magnetic hydrogel was fabricated, characterized, and evaluated for magnetic hyperthermia treatment. First, magnetic hydrogel was produced by a solution of alginate with magnetic nanoparticles in a bath of calcium chloride (5-15 mg mL-1) in order to achieve the external gelation and optimize the heating rate. The increased concentration (1-8 mg mL-1) of magnetic nanoparticles inside the hydrogel resulted in almost zero leakage of iron oxide nanoparticles after 15 days, guaranteeing that they can be used safely in biomedical applications. Thus, magnetic hybrid stents, which are based on the magnetic hydrogels, were developed in a simple way and were evaluated both in an agarose phantom model and in an ex vivo tissue sample at 30 mT and 765 kHz magnetic hyperthermia conditions to examine the heating efficiency. In both cases, hyperthermia results indicate excellent heat generation from the hybrid stent and facile temperature control via tuning magnetic nanoparticle concentration (2-8 mg mL-1). This study can be a promising method that promotes spatially thermal distribution in cancer treatment or restenosis treatment of hollow organs.
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Affiliation(s)
- Eirini Myrovali
- School of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece.,Magnetic Nanostructure Characterization: Technology and Applications, CIRI-AUTH, 57001 Thessaloniki, Greece
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Queiros Campos J, Boulares M, Raboisson-Michel M, Verger-Dubois G, García Fernández JM, Godeau G, Kuzhir P. Improved Magneto-Microfluidic Separation of Nanoparticles through Formation of the β-Cyclodextrin-Curcumin Inclusion Complex. Langmuir 2021; 37:14345-14359. [PMID: 34855402 DOI: 10.1021/acs.langmuir.1c02245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Molecular adsorption to the nanoparticle surface may switch the colloidal interactions from repulsive to attractive and promote nanoparticle agglomeration. If the nanoparticles are magnetic, then their agglomerates exhibit a much stronger response to external magnetic fields than individual nanoparticles. Coupling between adsorption, agglomeration, and magnetism allows a synergy between the high specific area of nanoparticles (∼100 m2/g) and their easy guidance or separation by magnetic fields. This yet poorly explored concept is believed to overcome severe restrictions for several biomedical applications of magnetic nanoparticles related to their poor magnetic remote control. In this paper, we test this concept using curcumin (CUR) binding (adsorption) to β-cyclodextrin (βCD)-coated iron oxide nanoparticles (IONP). CUR adsorption is governed by host-guest hydrophobic interactions with βCD through the formation of 1:1 and, possibly, 2:1 βCD:CUR inclusion complexes on the IONP surface. A 2:1 stoichiometry is supposed to promote IONP primary agglomeration, facilitating the formation of the secondary needle-like agglomerates under external magnetic fields and their magneto-microfluidic separation. The efficiency of these field-induced processes increases with CUR concentration and βCD surface density, while their relatively short timescale (<5 min) is compatible with magnetic drug delivery application.
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Affiliation(s)
- J Queiros Campos
- University Côte d'Azur, CNRS UMR 7010, Institute of Physics of Nice (INPHYNI) - Parc Valrose, Nice 06108, France
| | - M Boulares
- University of Carthage, Faculty of Sciences of Bizerte, Centre des Recherches et des Technologies des Eaux (CERTE) Technopole de Borj-Cédria, Route touristique de Soliman BPn° 273, Soliman 8020, Tunisia
| | - M Raboisson-Michel
- University Côte d'Azur, CNRS UMR 7010, Institute of Physics of Nice (INPHYNI) - Parc Valrose, Nice 06108, France
- Axlepios Biomedical, 1st Avenue, 5th Street, Carros 06510, France
| | - G Verger-Dubois
- Axlepios Biomedical, 1st Avenue, 5th Street, Carros 06510, France
| | - J M García Fernández
- Instituto de Investigaciones Qumicas, CSIC and Universidad de Sevilla, Av. Amrico Vespucio 49, Isla de la Cartuja, Sevilla 41092, Spain
| | - G Godeau
- University Côte d'Azur, CNRS UMR 7010, Institute of Physics of Nice (INPHYNI) - Parc Valrose, Nice 06108, France
| | - P Kuzhir
- University Côte d'Azur, CNRS UMR 7010, Institute of Physics of Nice (INPHYNI) - Parc Valrose, Nice 06108, France
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9
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Queiros Campos J, Checa-Fernandez BL, Marins JA, Lomenech C, Hurel C, Godeau G, Raboisson-Michel M, Verger-Dubois G, Bee A, Talbot D, Kuzhir P. Adsorption of Organic Dyes on Magnetic Iron Oxide Nanoparticles. Part II: Field-Induced Nanoparticle Agglomeration and Magnetic Separation. Langmuir 2021; 37:10612-10623. [PMID: 34436906 DOI: 10.1021/acs.langmuir.1c02021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
This paper (part II) is devoted to the effect of molecular adsorption on the surface of magnetic iron oxide nanoparticles (IONP) on the enhancement of their (secondary) field-induced agglomeration and magnetic separation. Experimentally, we use Methylene Blue (MB) cationic dye adsorption on citrate-coated maghemite nanoparticles to provoke primary agglomeration of IONP in the absence of the field. The secondary agglomeration is manifested through the appearance of needlelike micron-sized agglomerates in the presence of an applied magnetic field. With the increasing amount of adsorbed MB molecules, the size of the field-induced agglomerates increases and the magnetic separation on a magnetized micropillar becomes more efficient. These effects are mainly governed by the ratio of magnetic-to-thermal energy α, suspension supersaturation Δ0, and Brownian diffusivity Deff of primary agglomerates. The three parameters (α, Δ0, and Deff) are implicitly related to the surface coverage θ of IONP by MB molecules through the hydrodynamic size of primary agglomerates exponentially increasing with θ. Experiments and developed theoretical models allow quantitative evaluation of the θ effect on the efficiency of the secondary agglomeration and magnetic separation.
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Affiliation(s)
- J Queiros Campos
- Université Côte d'Azur, CNRS UMR 7010 Institute of Physics of Nice (INPHYNI), Parc Valrose, 06108 Nice, France
| | - B L Checa-Fernandez
- Department of Applied Physics, University of Granada, Avenida de la Fuente Nueva, 18071 Granada, Spain
- CEIT-Basque Research and Technology Alliance (BRTA) and Tecnun, University of Navarra, 20018 Donostia/San Sebastián, Spain
| | - J A Marins
- Université Côte d'Azur, CNRS UMR 7010 Institute of Physics of Nice (INPHYNI), Parc Valrose, 06108 Nice, France
| | - C Lomenech
- Université Côte d'Azur, CNRS UMR 7010 Institute of Physics of Nice (INPHYNI), Parc Valrose, 06108 Nice, France
| | - Ch Hurel
- Université Côte d'Azur, CNRS UMR 7010 Institute of Physics of Nice (INPHYNI), Parc Valrose, 06108 Nice, France
| | - G Godeau
- Université Côte d'Azur, CNRS UMR 7010 Institute of Physics of Nice (INPHYNI), Parc Valrose, 06108 Nice, France
| | - M Raboisson-Michel
- Université Côte d'Azur, CNRS UMR 7010 Institute of Physics of Nice (INPHYNI), Parc Valrose, 06108 Nice, France
- Axlepios Biomedical, 1ere Avenue 5eme rue, 06510 Carros, France
| | - G Verger-Dubois
- Axlepios Biomedical, 1ere Avenue 5eme rue, 06510 Carros, France
| | - A Bee
- Sorbonne Université, CNRS, UMR 8234, PHENIX, 4 place Jussieu, 75252 Paris Cedex 5, France
| | - D Talbot
- Sorbonne Université, CNRS, UMR 8234, PHENIX, 4 place Jussieu, 75252 Paris Cedex 5, France
| | - P Kuzhir
- Université Côte d'Azur, CNRS UMR 7010 Institute of Physics of Nice (INPHYNI), Parc Valrose, 06108 Nice, France
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10
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Marć M, Drzewiński A, Wolak WW, Najder-Kozdrowska L, Dudek MR. Filtration of Nanoparticle Agglomerates in Aqueous Colloidal Suspensions Exposed to an External Radio-Frequency Magnetic Field. Nanomaterials (Basel) 2021; 11:1737. [PMID: 34361123 PMCID: PMC8307179 DOI: 10.3390/nano11071737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 06/27/2021] [Accepted: 06/28/2021] [Indexed: 12/07/2022]
Abstract
The study investigated the phenomenon of the fast aggregation of single-domain magnetic iron oxide nanoparticles in stable aqueous colloidal suspensions due to the presence of a radio-frequency (RF) magnetic field. Single-domain nanoparticles have specific magnetic properties, especially the unique property of absorbing the energy of such a field and releasing it in the form of heat. The localized heating causes the colloid to become unstable, leading to faster agglomeration of nanoparticles and, consequently, to rapid sedimentation. It has been shown that the destabilization of a stable magnetic nanoparticle colloid by the RF magnetic field can be used for the controlled filtration of larger agglomerates of the colloid solution. Two particular cases of stable colloidal suspensions were considered: a suspension of the bare nanoparticles in an alkaline solution and the silica-stabilized nanoparticles in a neutral solution. The obtained results are important primarily for biomedical applications and wastewater treatment.
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Affiliation(s)
| | - Andrzej Drzewiński
- Institute of Physics, University of Zielona Góra, ul. Szafrana 4a, 65-069 Zielona Góra, Poland; (M.M.); (W.W.W.); (L.N.-K.); (M.R.D.)
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11
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Farkaš B, de Leeuw NH. A Perspective on Modelling Metallic Magnetic Nanoparticles in Biomedicine: From Monometals to Nanoalloys and Ligand-Protected Particles. Materials (Basel) 2021; 14:3611. [PMID: 34203371 PMCID: PMC8269646 DOI: 10.3390/ma14133611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 12/24/2022]
Abstract
The focus of this review is on the physical and magnetic properties that are related to the efficiency of monometallic magnetic nanoparticles used in biomedical applications, such as magnetic resonance imaging (MRI) or magnetic nanoparticle hyperthermia, and how to model these by theoretical methods, where the discussion is based on the example of cobalt nanoparticles. Different simulation systems (cluster, extended slab, and nanoparticle models) are critically appraised for their efficacy in the determination of reactivity, magnetic behaviour, and ligand-induced modifications of relevant properties. Simulations of the effects of nanoscale alloying with other metallic phases are also briefly reviewed.
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Affiliation(s)
- Barbara Farkaš
- School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK;
| | - Nora H. de Leeuw
- School of Chemistry, Cardiff University, Cardiff CF10 3AT, UK;
- School of Chemistry, University of Leeds, Leeds LS2 9JT, UK
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12
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Silva FG, Depeyrot J, Raikher YL, Stepanov VI, Poperechny IS, Aquino R, Ballon G, Geshev J, Dubois E, Perzynski R. Exchange-bias and magnetic anisotropy fields in core-shell ferrite nanoparticles. Sci Rep 2021; 11:5474. [PMID: 33750828 PMCID: PMC7970917 DOI: 10.1038/s41598-021-84843-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 02/22/2021] [Indexed: 11/09/2022] Open
Abstract
Exchange bias properties of MnFe\documentclass[12pt]{minimal}
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\begin{document}$$_3$$\end{document}3 core–shell nanoparticles are investigated. The measured field and temperature dependencies of the magnetization point out a well-ordered ferrimagnetic core surrounded by a layer with spin glass-like arrangement. Quasi-static SQUID magnetization measurements are presented along with high-amplitude pulse ones and are cross-analyzed by comparison against ferromagnetic resonance experiments at 9 GHz. These measurements allow one to discern three types of magnetic anisotropies affecting the dynamics of the magnetic moment of the well-ordered ferrimagnetic NP’s core viz. the easy-axis (uniaxial) anisotropy, the unidirectional exchange-bias anisotropy and the rotatable anisotropy. The uniaxial anisotropy originates from the structural core–shell interface. The unidirectional exchange-bias anisotropy is associated with the spin-coupling at the ferrimagnetic/spin glass-like interface; it is observable only at low temperatures after a field-cooling process. The rotatable anisotropy is caused by partially-pinned spins at the core/shell interface; it manifests itself as an intrinsic field always parallel to the external applied magnetic field. The whole set of experimental results is interpreted in the framework of superparamagnetic theory, i.e., essentially taking into account the effect of thermal fluctuations on the magnetic moment of the particle core. In particular, it is found that the rotatable anisotropy of our system is of a uniaxial type.
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Affiliation(s)
- F G Silva
- Instituto de Física, Universidade de Brasília, Caixa Postal 04455, Brasília, 70919-970, Brazil. .,Sorbonne Université, CNRS, PHENIX UMR 8234, 75005, Paris, France. .,Faculdade UnB Planaltina, Universidade de Brasília, Planaltina (DF), 73345-010, Brazil.
| | - J Depeyrot
- Instituto de Física, Universidade de Brasília, Caixa Postal 04455, Brasília, 70919-970, Brazil
| | - Yu L Raikher
- Institute of Continuous Media Mechanics, Ural Branch of RAS, Perm, 614068, Russia.,Institute of Natural Sciences and Mathematics, Ural Federal University, Ekaterinburg, 620083, Russia
| | - V I Stepanov
- Institute of Continuous Media Mechanics, Ural Branch of RAS, Perm, 614068, Russia
| | - I S Poperechny
- Institute of Continuous Media Mechanics, Ural Branch of RAS, Perm, 614068, Russia.,Department of Phase Transitions Physics, Perm State National Research University, Perm, 614990, Russia
| | - R Aquino
- Faculdade UnB Planaltina, Universidade de Brasília, Planaltina (DF), 73345-010, Brazil
| | - G Ballon
- CNRS-LNCMI, 31400, Toulouse, France
| | - J Geshev
- Instituto de Fisica, UFRGS, Porto Alegre, RS, 91501-970, Brazil
| | - E Dubois
- Sorbonne Université, CNRS, PHENIX UMR 8234, 75005, Paris, France
| | - R Perzynski
- Sorbonne Université, CNRS, PHENIX UMR 8234, 75005, Paris, France
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