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Salvador MA, Costa AS, Gaeti M, Mendes LP, Lima EM, Bakuzis AF, Miotto R. Characterization, nanoparticle self-organization, and Monte Carlo simulation of magnetoliposomes. Phys Rev E 2016; 93:022609. [PMID: 26986379 DOI: 10.1103/physreve.93.022609] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Indexed: 05/15/2023]
Abstract
In this work we have developed and implement a new approach for the study of magnetoliposomes using Monte Carlo simulations. Our model is based on interaction among nanoparticles considering magnetic dipolar, van der Waals, ionic-steric, and Zeeman interaction potentials. The ionic interaction between nanoparticles and the lipid bilayer is represented by an ionic repulsion electrical surface potential that depends on the nanoparticle-lipid bilayer distance and the concentration of ions in the solution. A direct comparison among transmission electron microscopy, vibrating sample magnetometer, dynamic light scattering, nanoparticle tracking analysis, and experimentally derived static magnetic birefringence and simulation data allow us to validate our implementation. Our simulations suggest that confinement plays an important role in aggregate formation.
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Affiliation(s)
- Michele Aparecida Salvador
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adelia 166, CEP 09210-170, Santo André, SP, Brazil
| | - Anderson Silva Costa
- Instituto de Física, Universidade Federal de Goiás, CEP 74.690-900, Goiânia, Go, Brazil
| | - Marilisa Gaeti
- Faculdade de Farmácia, Universidade Federal de Goiás, CEP 74605-220, Goiânia, Go, Brazil
| | | | - Eliana Martins Lima
- Faculdade de Farmácia, Universidade Federal de Goiás, CEP 74605-220, Goiânia, Go, Brazil
| | | | - Ronei Miotto
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adelia 166, CEP 09210-170, Santo André, SP, Brazil
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Blanco-Andujar C, Ortega D, Southern P, Nesbitt SA, Thanh NTK, Pankhurst QA. Real-time tracking of delayed-onset cellular apoptosis induced by intracellular magnetic hyperthermia. Nanomedicine (Lond) 2016; 11:121-36. [DOI: 10.2217/nnm.15.185] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Aim: To assess cell death pathways in response to magnetic hyperthermia. Materials & methods: Human melanoma cells were loaded with citric acid-coated iron-oxide nanoparticles, and subjected to a time-varying magnetic field. Pathways were monitored in vitro in suspensions and in situ in monolayers using fluorophores to report on early-stage apoptosis and late-stage apoptosis and/or necrosis. Results: Delayed-onset effects were observed, with a rate and extent proportional to the thermal-load-per-cell. At moderate loads, membranal internal-to-external lipid exchange preceded rupture and death by a few hours (the timeline varying cell-to-cell), without any measurable change in the local environment temperature. Conclusion: Our observations support the proposition that intracellular heating may be a viable, controllable and nonaggressive in vivo treatment for human pathological conditions.
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Affiliation(s)
- Cristina Blanco-Andujar
- Healthcare Biomagnetics Laboratory, University College London, 21 Albemarle Street, London, W1S 4BS, UK
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR-7504 CNRS-Université de Strasbourg, 23 rue du Loess, BP 43 67034 Strasbourg Cedex 2, France
| | - Daniel Ortega
- Healthcare Biomagnetics Laboratory, University College London, 21 Albemarle Street, London, W1S 4BS, UK
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco 28049, Madrid, Spain
- Nanobiotecnología (IMDEA-Nanociencia), Unidad Asociada al Centro Nacional de Biotecnología (CSIC), Cantoblanco 28049, Madrid, Spain
| | - Paul Southern
- Healthcare Biomagnetics Laboratory, University College London, 21 Albemarle Street, London, W1S 4BS, UK
| | - Stephen A Nesbitt
- Healthcare Biomagnetics Laboratory, University College London, 21 Albemarle Street, London, W1S 4BS, UK
| | - Nguyễn Thị Kim Thanh
- Healthcare Biomagnetics Laboratory, University College London, 21 Albemarle Street, London, W1S 4BS, UK
- Biophysics Group, Department of Physics & Astronomy, University College London, Gower Street, London, WC1E 6BT, UK
| | - Quentin A Pankhurst
- Healthcare Biomagnetics Laboratory, University College London, 21 Albemarle Street, London, W1S 4BS, UK
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Blanco-Andujar C, Ortega D, Southern P, Pankhurst QA, Thanh NTK. High performance multi-core iron oxide nanoparticles for magnetic hyperthermia: microwave synthesis, and the role of core-to-core interactions. NANOSCALE 2015; 7:1768-75. [PMID: 25515238 DOI: 10.1039/c4nr06239f] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The adoption of magnetic hyperthermia as either a stand-alone or adjunct therapy for cancer is still far from being optimised due to the variable performance found in many iron oxide nanoparticle systems, including commercially available formulations. Herein, we present a reproducible and potentially scalable microwave-based method to make stable citric acid coated multi-core iron oxide nanoparticles, with exceptional magnetic heating parameters, viz. intrinsic loss parameters (ILPs) of up to 4.1 nH m(2) kg(-1), 35% better than the best commercial equivalents. We also probe the core-to-core magnetic interactions in the particles via remanence-derived Henkel and ΔM plots. These reveal a monotonic dependence of the ILP on the magnetic interaction field Hint, and show that the interactions are demagnetising in nature, and act to hinder the magnetic heating mechanism.
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Affiliation(s)
- C Blanco-Andujar
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, UK.
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Joseph A, Mathew S. Ferrofluids: Synthetic Strategies, Stabilization, Physicochemical Features, Characterization, and Applications. Chempluschem 2014. [DOI: 10.1002/cplu.201402202] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Ketkar-Atre A, Struys T, Soenen SJ, Lambrichts I, Verfaillie CM, De Cuyper M, Himmelreich U. Variability in contrast agent uptake by different but similar stem cell types. Int J Nanomedicine 2013; 8:4577-91. [PMID: 24399873 PMCID: PMC3876490 DOI: 10.2147/ijn.s51588] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The need to track and evaluate the fate of transplanted cells is an important issue in regenerative medicine. In order to accomplish this, pre-labelling cells with magnetic resonance imaging (MRI) contrast agents is a well-established method. Uptake of MRI contrast agents by non-phagocytic stem cells, and factors such as cell homeostasis or the adverse effects of contrast agents on cell biology have been extensively studied, but in the context of nanoparticle (NP)-specific parameters. Here, we have studied three different types of NPs (Endorem®, magnetoliposomes [MLs], and citrate coated C-200) to label relatively larger, mesenchymal stem cells (MSCs) and, much smaller yet faster proliferating, multipotent adult progenitor cells (MAPCs). Both cell types are similar, as they are isolated from bone marrow and have substantial regenerative potential, which make them interesting candidates for comparative experiments. Using NPs with different surface coatings and sizes, we found that differences in the proliferative and morphological characteristics of the cells used in the study are mainly responsible for the fate of endocytosed iron, intracellular iron concentration, and cytotoxic responses. The quantitative analysis, using high-resolution electron microscopy images, demonstrated a strong relationship between cell volume/surface, uptake, and cytotoxicity. Interestingly, uptake and toxicity trends are reversed if intracellular concentrations, and not amounts, are considered. This indicates that more attention should be paid to cellular parameters such as cell size and proliferation rate in comparative cell-labeling studies.
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Affiliation(s)
- Ashwini Ketkar-Atre
- Biomedical MRI/MoSAIC, Department of Imaging and Pathology, Biomedical Sciences Group, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Tom Struys
- Biomedical MRI/MoSAIC, Department of Imaging and Pathology, Biomedical Sciences Group, Katholieke Universiteit Leuven, Leuven, Belgium ; Lab of Histology, Biomedical Research Institute, Hasselt University, Campus Diepenbeek, Agoralaan, Diepenbeek, Belgium
| | - Stefaan J Soenen
- Lab for General Biochemistry and Physical Pharmacy, Faculty of Pharmacy, Ghent University, Ghent, Belgium
| | - Ivo Lambrichts
- Lab of Histology, Biomedical Research Institute, Hasselt University, Campus Diepenbeek, Agoralaan, Diepenbeek, Belgium
| | - Catherine M Verfaillie
- Interdepartmental Stem Cell Institute, O&N IV, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Marcel De Cuyper
- Laboratory of BioNanoColloids, Interdisciplinary Research Centre, Katholieke Universiteit Leuven, Kortrijk, Belgium
| | - Uwe Himmelreich
- Biomedical MRI/MoSAIC, Department of Imaging and Pathology, Biomedical Sciences Group, Katholieke Universiteit Leuven, Leuven, Belgium
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Bakuzis AF, Branquinho LC, Luiz e Castro L, de Amaral e Eloi MT, Miotto R. Chain formation and aging process in biocompatible polydisperse ferrofluids: experimental investigation and Monte Carlo simulations. Adv Colloid Interface Sci 2013; 191-192:1-21. [PMID: 23360743 DOI: 10.1016/j.cis.2012.12.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Revised: 12/27/2012] [Accepted: 12/28/2012] [Indexed: 11/25/2022]
Abstract
We review the use of Monte Carlo simulations in the description of magnetic nanoparticles dispersed in a liquid carrier. Our main focus is the use of theory and simulation as tools for the description of the properties of ferrofluids. In particular, we report on the influence of polydispersity and short-range interaction on the self-organization of nanoparticles. Such contributions are shown to be extremely important for systems characterized by particles with diameters smaller than 10nm. A new 3D polydisperse Monte Carlo implementation for biocompatible magnetic colloids is proposed. As an example, theoretical and simulation results for an ionic-surfacted ferrofluid dispersed in a NaCl solution are directly compared to experimental data (transmission electron microscopy - TEM, magneto-transmissivity, and electron magnetic resonance - EMR). Our combined theoretical and experimental results suggest that during the aging process two possible mechanisms are likely to be observed: the nanoparticle's grafting decreases due to aggregate formation and the Hamaker constant increases due to oxidation. In addition, we also briefly discuss theoretical agglomerate formation models and compare them to experimental data.
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Hodenius M, Hieronymus T, Zenke M, Becker C, Elling L, Bornemann J, Wong JE, Richtering W, Himmelreich U, De Cuyper M. Magnetically triggered clustering of biotinylated iron oxide nanoparticles in the presence of streptavidinylated enzymes. NANOTECHNOLOGY 2012; 23:355707. [PMID: 22894914 DOI: 10.1088/0957-4484/23/35/355707] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This work deals with the production and characterization of water-compatible, iron oxide based nanoparticles covered with functional poly(ethylene glycol) (PEG)-biotin surface groups (SPIO-PEG-biotin). Synthesis of the functionalized colloids occurred by incubating the oleate coated particles used as precursor magnetic fluid with anionic liposomes containing 14 mol% of a phospholipid-PEG-biotin conjugate. The latter was prepared by coupling dimyristoylphosphatidylethanolamine (DC(14:0)PE) to activated α-biotinylamido-ω -N-hydroxy-succinimidcarbonyl-PEG (NHS-PEG-biotin). Physical characterization of the oleate and PEG-biotin iron oxide nanocolloids revealed that they appear as colloidal stable clusters with a hydrodynamic diameter of 160 nm and zeta potentials of - 39 mV (oleate coated particles) and - 14 mV (PEG-biotin covered particles), respectively, as measured by light scattering techniques. Superconducting quantum interference device (SQUID) measurements revealed specific saturation magnetizations of 62-73 emu g(-1) Fe(3)O(4) and no hysteresis was observed at 300 K. MR relaxometry at 3 T revealed very high r(2) relaxivities and moderately high r(1) values. Thus, both nanocolloids can be classified as small, superparamagnetic, negative MR contrast agents. The capacity to functionalize the particles was illustrated by binding streptavidin alkaline phosphatase (SAP). It was found, however, that these complexes become highly aggregated after capturing them on the magnetic filter device during high-gradient magnetophoresis, thereby reducing the accessibility of the SAP.
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Affiliation(s)
- Michael Hodenius
- Interdisciplinary Research Centre, K U Leuven-Campus Kortrijk, Kortrijk, Belgium.
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Mapping of Proton Relaxation Near Superparamagnetic Iron Oxide Particle–Loaded Polymer Threads for Magnetic Susceptibility Difference Quantification. Invest Radiol 2012; 47:359-67. [DOI: 10.1097/rli.0b013e3182484fdf] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Hodenius M, Würth C, Jayapaul J, Wong JE, Lammers T, Gätjens J, Arns S, Mertens N, Slabu I, Ivanova G, Bornemann J, Cuyper MD, Resch-Genger U, Kiessling F. Fluorescent magnetoliposomes as a platform technology for functional and molecular MR and optical imaging. CONTRAST MEDIA & MOLECULAR IMAGING 2012; 7:59-67. [DOI: 10.1002/cmmi.467] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
| | - Christian Würth
- Federal Institute for Materials Research and Testing; Berlin; Germany
| | - Jabadurai Jayapaul
- Department of Experimental Molecular Imaging; RWTH Aachen University; Aachen; Germany
| | - John E. Wong
- Chemical Process Engineering; RWTH Aachen University; Aachen; Germany
| | - Twan Lammers
- Department of Experimental Molecular Imaging; RWTH Aachen University; Aachen; Germany
| | - Jessica Gätjens
- Department of Experimental Molecular Imaging; RWTH Aachen University; Aachen; Germany
| | - Susanne Arns
- Department of Experimental Molecular Imaging; RWTH Aachen University; Aachen; Germany
| | - Natascha Mertens
- Department of Experimental Molecular Imaging; RWTH Aachen University; Aachen; Germany
| | - Ioana Slabu
- Applied Medical Engineering; Helmholtz-Institute, RWTH Aachen University; Germany
| | - Gergana Ivanova
- Applied Medical Engineering; Helmholtz-Institute, RWTH Aachen University; Germany
| | - Jörg Bornemann
- Elektronenmikroskopische Einrichtung; RWTH Aachen University; Aachen; Germany
| | - Marcel De Cuyper
- Interdisciplinary Research Centre; K.U.Leuven-Campus Kortrijk; Kortrijk; Belgium
| | | | - Fabian Kiessling
- Department of Experimental Molecular Imaging; RWTH Aachen University; Aachen; Germany
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Galvin P, Thompson D, Ryan KB, McCarthy A, Moore AC, Burke CS, Dyson M, Maccraith BD, Gun'ko YK, Byrne MT, Volkov Y, Keely C, Keehan E, Howe M, Duffy C, MacLoughlin R. Nanoparticle-based drug delivery: case studies for cancer and cardiovascular applications. Cell Mol Life Sci 2012; 69:389-404. [PMID: 22015612 PMCID: PMC11115117 DOI: 10.1007/s00018-011-0856-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 09/29/2011] [Accepted: 09/29/2011] [Indexed: 11/25/2022]
Abstract
Nanoparticles (NPs) comprised of nanoengineered complexes are providing new opportunities for enabling targeted delivery of a range of therapeutics and combinations. A range of functionalities can be included within a nanoparticle complex, including surface chemistry that allows attachment of cell-specific ligands for targeted delivery, surface coatings to increase circulation times for enhanced bioavailability, specific materials on the surface or in the nanoparticle core that enable storage of a therapeutic cargo until the target site is reached, and materials sensitive to local or remote actuation cues that allow controlled delivery of therapeutics to the target cells. However, despite the potential benefits of NPs as smart drug delivery and diagnostic systems, much research is still required to evaluate potential toxicity issues related to the chemical properties of NP materials, as well as their size and shape. The need to validate each NP for safety and efficacy with each therapeutic compound or combination of therapeutics is an enormous challenge, which forces industry to focus mainly on those nanoparticle materials where data on safety and efficacy already exists, i.e., predominantly polymer NPs. However, the enhanced functionality affordable by inclusion of metallic materials as part of nanoengineered particles provides a wealth of new opportunity for innovation and new, more effective, and safer therapeutics for applications such as cancer and cardiovascular diseases, which require selective targeting of the therapeutic to maximize effectiveness while avoiding adverse effects on non-target tissues.
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Affiliation(s)
- Paul Galvin
- Tyndall National Institute, University College Cork, Cork, Ireland.
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Schwarz S, Wong JE, Bornemann J, Hodenius M, Himmelreich U, Richtering W, Hoehn M, Zenke M, Hieronymus T. Polyelectrolyte coating of iron oxide nanoparticles for MRI-based cell tracking. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2011; 8:682-91. [PMID: 21893141 DOI: 10.1016/j.nano.2011.08.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 08/12/2011] [Accepted: 08/12/2011] [Indexed: 11/30/2022]
Abstract
UNLABELLED Iron oxide-based magnetic nanoparticles (MNPs) offer unique properties for cell tracking by magnetic resonance imaging (MRI) in cellular immunotherapy. In this study, we investigated the uptake of chemically engineered NPs into antigen-presenting dendritic cells (DCs). DCs are expected to perceive MNPs as foreign antigens, thus exhibiting the capability to immunologically sense MNP surface chemistry. To systematically evaluate cellular uptake and T2/T2(⁎) MR imaging properties of MNPs, we synthesized polymer-based MNPs by employing layer-by-layer (LbL) technology. Thereby, we achieved modification of particle shell parameters, such as size, surface charge, and chemistry. We found that subcellular packaging of MNPs rather than MNP content in DCs influences MR imaging quality. Increased local intracellular electron density as inferred from transmission electron microscopy (TEM) strongly correlated with enhanced contrast in MRI. Thus, LbL-tailoring of MNP shells using polyelectrolytes that impact on uptake and subcellular localization can be used for modulating MR imaging properties. FROM THE CLINICAL EDITOR In this study, layer-by-layer tailoring of magnetic NP shells was performed using polyelectrolytes to improve uptake by dendritic cells for cell-specific MR imaging. The authors conclude that polyelectrolyte modified NP-s can be used for modulating improving MR imaging quality by increasing subcellular localization.
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Affiliation(s)
- Sebastian Schwarz
- Institute for Biomedical Engineering, Department of Cell Biology, University Hospital RWTH Aachen University, Aachen, Germany
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Ghosh S, Carty D, Clarke SP, Corr SA, Tekoriute R, Gun'ko YK, Brougham DF. NMR studies into colloidal stability and magnetic order in fatty acid stabilised aqueous magnetic fluids. Phys Chem Chem Phys 2010; 12:14009-16. [DOI: 10.1039/c0cp00989j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Heinrichs U, Utting JF, Frauenrath T, Hezel F, Krombach GA, Hodenius MA, Kozerke S, Niendorf T. MyocardialT2*mapping free of distortion using susceptibility-weighted fast spin-echo imaging: A feasibility study at 1.5 T and 3.0 T. Magn Reson Med 2009; 62:822-8. [DOI: 10.1002/mrm.22054] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Hodenius M, Schmitz-Rode T, Baumann M, Ivanova G, Wong J, Mang T, Haulena F, Soenen S, De Cuyper M. Absorption of 10-hydroxycamptothecin into the coat of magnetoliposomes. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2009.01.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Thermoablation of malignant kidney tumors using magnetic nanoparticles: an in vivo feasibility study in a rabbit model. Cardiovasc Intervent Radiol 2009; 33:127-34. [PMID: 19430744 DOI: 10.1007/s00270-009-9583-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 04/03/2009] [Accepted: 04/07/2009] [Indexed: 10/20/2022]
Abstract
The objective of this study was to assess the technical feasibility of CT-guided magnetic thermoablation for the treatment of malignant kidney tumors in a VX2 tumor rabbit model. VX2 tumors were implanted into the kidneys of five rabbits and allowed to grow for 2 weeks. After preinterventional CT perfusion imaging, CT-guided injection of superparamagnetic iron oxide particles (300 microl) was performed, followed by exposure of the animals to an alternating electromagnetic field for 15 min (approximately 0.32 kA/m). Then animals underwent CT perfusion imaging again. Afterward, animals were sacrificed and kidneys were dissected for macroscopic and histological evaluation. Changes in perfusion before and after exposure to the alternating magnetic field were analyzed. In one animal no tumor growth could be detected so the animal was used for optimization of the ablation procedure including injection technique and peri-interventional cross-sectional imaging (CT, MRI). After image-guided intratumoral injection of ferrofluids, the depiction of nanoparticle distribution by CT correlated well with macroscopic evaluation of the dissected kidneys. MRI was limited due to severe susceptibility artefacts. Postinterventional CT perfusion imaging revealed a perfusion deficiency around the ferrofluid deposits. Histological workup showed different zones of thermal damage adjacent to the ferrofluid deposits. In conclusion, CT-guided magnetic thermoablation of malignant kidney tumors is technically feasible in an animal model and results in a perfusion deficiency indicating tumor necrosis as depicted by CT perfusion imaging and shown in histological evaluation.
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Barick KC, Aslam M, Lin YP, Bahadur D, Prasad PV, Dravid VP. Novel and efficient MR active aqueous colloidal Fe3O4 nanoassemblies. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b911626e] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Qiu X, Li G, Sun X, Li L, Fu X. Doping effects of Co(2+) ions on ZnO nanorods and their photocatalytic properties. NANOTECHNOLOGY 2008; 19:215703. [PMID: 21730582 DOI: 10.1088/0957-4484/19/21/215703] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A series of Zn(1-x)Co(x)O nanorods with dopant content ranging from x = 0.00 to 0.10 was prepared by a wet chemical method. All Zn(1-x)Co(x)O samples were investigated by x-ray diffraction, transmission electron microscopy, energy-dispersion x-ray line mapping analysis, and UV-visible absorption spectroscopy. It was found that Co(2+) ions were homogeneously substituted for Zn(2+) ions in ZnO nanorods. Rhodamine B degradation was used as a probe reaction to evaluate the effect of Co(2+) doping on ZnO nanorods and photocatalytic performance under UV light and visible light irradiation. Co(2+) ions acted as the trapping or recombination centers for electrons and holes, leading to a reduction in photodegradation efficiency under UV light illumination. Alternatively, Co(2+) ions enhanced the optical absorption and produced the photoinduced carriers under visible illumination in terms of two charge transfer transitions involving Co(2+) ions. Consequently, Co(2+) ions substituted in the lattice of ZnO nanorods significantly improved the visible light photocatalytic activity.
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Affiliation(s)
- Xiaoqing Qiu
- State Key Lab of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, and Graduate School of Chinese Academy of Sciences, Fuzhou 350002, People's Republic of China
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