Fabrication of magnetic nanorods and their applications in medicine

Ramzannezhad, Ali; Gill, Pooria; Bahari, Ali

doi:10.1515/bnm-2017-0008

Cited by 16 publications

(9 citation statements)

References 77 publications

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“…Elongated magnetic nanoparticles, mainly nanorods, have been of interest in various industrial [61,62], and biomedical applications [63][64][65]. Classification is based on the external energy required for inversion of the magnetization [61]. Nanorods encompass structures with some nanometers of diameter and length up to 100 nm, while the length of nanowires is larger, and nanotubes are hollow nanorods [23].…”

Section: Elongated Nanoparticlesmentioning

confidence: 99%

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Andrade

Veloso

Castanheira

2020

IJMS

123

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Research on iron oxide-based magnetic nanoparticles and their clinical use has been, so far, mainly focused on the spherical shape. However, efforts have been made to develop synthetic routes that produce different anisotropic shapes not only in magnetite nanoparticles, but also in other ferrites, as their magnetic behavior and biological activity can be improved by controlling the shape. Ferrite nanoparticles show several properties that arise from finite-size and surface effects, like high magnetization and superparamagnetism, which make them interesting for use in nanomedicine. Herein, we show recent developments on the synthesis of anisotropic ferrite nanoparticles and the importance of shape-dependent properties for biomedical applications, such as magnetic drug delivery, magnetic hyperthermia and magnetic resonance imaging. A brief discussion on toxicity of iron oxide nanoparticles is also included.

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Section: Elongated Nanoparticlesmentioning

confidence: 99%

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Andrade

Veloso

Castanheira

2020

IJMS

123

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“…It is well established that shape anisotropy of nanoparticles leads to an enhancement of the dissipated heat since it adds to the magnetic anisotropy, and has a non-negligible effect on the time-dependent hysteresis of the particles. It has been shown, for example, that magnetite nanocubes [41] and nanorods [42,43] have a higher specific adsorption rate than spherical nanoparticles of similar size and made of the same material. While some investigations hint at the effect of sodium and potassium cations in driving the shape transition from spherical to cubic [44], the factors affecting the change in shape from spherical to ellipsoidal remain elusive, and might be related to the temperature profile imposed during the synthesis.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the Shape Anisotropy of Superparamagnetic Iron Oxide Nanoparticles during Thermal Decomposition

et al. 2020

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Magnetosomes are near-perfect intracellular magnetite nanocrystals found in magnetotactic bacteria. Their synthetic imitation, known as superparamagnetic iron oxide nanoparticles (SPIONs), have found applications in a variety of (nano)medicinal fields such as magnetic resonance imaging contrast agents, multimodal imaging and drug carriers. In order to perform these functions in medicine, shape and size control of the SPIONs is vital. We sampled SPIONs at ten-minutes intervals during the high-temperature thermal decomposition reaction. Their shape (sphericity and anisotropy) and geometric description (volume and surface area) were retrieved using three-dimensional imaging techniques, which allowed to reconstruct each particle in three dimensions, followed by stereological quantification methods. The results, supported by small angle X-ray scattering characterization, reveal that SPIONs initially have a spherical shape, then grow increasingly asymmetric and irregular. A high heterogeneity in volume at the initial stages makes place for lower particle volume dispersity at later stages. The SPIONs settled into a preferred orientation on the support used for transmission electron microscopy imaging, which hides the extent of their anisotropic nature in the axial dimension, there by biasing the interpretation of standard 2D micrographs. This information could be feedback into the design of the chemical processes and the characterization strategies to improve the current applications of SPIONs in nanomedicine.

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“…Among the different routes to iron oxide nanorods for biomedical applications listed in a recent review paper, one common technique is a two-step synthesis consisting first of the preparation of akaganeite (β-FeOOH) rods (iron oxyhydroxide with weak paramagnetic properties at room temperature), followed by a reduction to ferrimagnetic iron oxide (magnetite or maghemite) . Nanosized akaganeite rods are obtained through the hydrolysis of iron chloride (FeCl 3 ) in mild acidic or alkaline conditions in the presence of size capping agents such as dopamine, poly(ethyleneimine) (PEI), , or oleic acid .…”

Section: Introductionmentioning

confidence: 99%

Colloidal Stability of Aqueous Suspensions of Polymer-Coated Iron Oxide Nanorods: Implications for Biomedical Applications

Marins

Montagnon

Ezzaier

et al. 2018

ACS Appl. Nano Mater.

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Iron oxide nanorods are considered to be very promising platforms for biomedical applications, such as magnetic hyperthermia, magnetic resonance imaging, or immunoassays based on magnetooptical effects. However, their efficient colloidal stabilization is challenging, and colloidal aggregation could lead to the total loss of their performance. This work is focused on the synthesis and colloidal stabilization of iron oxide nanorods of an average length and diameter, L × d = 31 × 6 nm, synthesized by the hydrolysis of iron(III) salt, followed by reduction of the obtained akaganeite to iron oxide in a microwave reactor. Synthesized nanorods exhibited a weak ferrimagnetic behavior with remnant magnetization M R ∼ 3 emu/g and saturation magnetization M S ∼ 13 emu/g. The nanorods were dispersed in water after adsorption on their surface of three different polymers: linear bisphosphonate–poly(ethylene glycol) (PEG) molecules (denoted as OPT), polymethacrylate backbone/PEG side chains comb polymer (denoted as PCP; with PEG brushes both extended toward the solvent and having molecular weight M w ∼ 3000 g/mol), and polyacrylic sodium salt (PAA; M w ∼ 15000 g/mol). Experiments and theoretical evaluation of the interaction potential show that increasing the polymer grafting density on the nanorod surface as well as decreasing the concentration of a nonadsorbed polymer improve the nanorod colloidal stability. The best stability is obtained on an optimal range of weight ratio of the added polymer to the nanorods between 0.5 and 1.6 mg/mg. A higher grafting density reached with a OPT polymer with a bisphosphonate terminal group (2–4 nm–2) allows much better stability than using multiple adsorption with PCP (0.2–0.4 nm–2) or PAA. Even though the nanorods are still subject to some aggregation (effective hydrodynamic diameter ∼60 nm, compared to their TEM size of L × d = 31 × 6 nm), significant progress toward understanding their colloidal stability was achieved.

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Fabrication of magnetic nanorods and their applications in medicine

Cited by 16 publications

References 77 publications

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

Characterization of the Shape Anisotropy of Superparamagnetic Iron Oxide Nanoparticles during Thermal Decomposition

Colloidal Stability of Aqueous Suspensions of Polymer-Coated Iron Oxide Nanorods: Implications for Biomedical Applications

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