Synthesis of very fine maghemite particles

Bée, Agnès; Massart, R.; Neveu, Sophie

doi:10.1016/0304-8853(95)00317-7

Cited by 474 publications

(348 citation statements)

References 9 publications

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“…Bare SPIO (i.e., without surface complexing agents) are created following the addition of a concentrated base to a di-and trivalent ferrous salt solution. 13 The precipitate is isolated through magnetic decantation or centrifugation. The precipitate is then treated with nitric or perchloric acid, centrifuged and peptized (i.e., colloidally dispersed) in water.…”

Section: Coprecipitationmentioning

confidence: 99%

“…87 These magnetite nanoparticles are polydisperse with a mean diameter of approximately 10 nm and are roughly spherical in shape. 13 Bare SPIO can subsequently be coated in monomers and polymers (Table 2) through non-specific adsorption following their purification to make them more suited for biomedical applications. 109 Alternatively, the monomers and polymers may be grafted to the nanoparticles during the precipitation step, although this will change the physical characteristics of the resulting nanoparticles.…”

Section: Coprecipitationmentioning

confidence: 99%

“…109 Alternatively, the monomers and polymers may be grafted to the nanoparticles during the precipitation step, although this will change the physical characteristics of the resulting nanoparticles. 13,32 One commonly used coating for bare SPIO is silica. An advantage of coating contrast agents with silica is that one is able to tap the established database for silica surface modification.…”

Section: Coprecipitationmentioning

confidence: 99%

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Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging

et al. 2006

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Abstract-The field of molecular imaging has recently seen rapid advances in the development of novel contrast agents and the implementation of insightful approaches to monitor biological processes non-invasively. In particular, superparamagnetic iron oxide nanoparticles (SPIO) have demonstrated their utility as an important tool for enhancing magnetic resonance contrast, allowing researchers to monitor not only anatomical changes, but physiological and molecular changes as well. Applications have ranged from detecting inflammatory diseases via the accumulation of non-targeted SPIO in infiltrating macrophages to the specific identification of cell surface markers expressed on tumors. In this article, we attempt to illustrate the broad utility of SPIO in molecular imaging, including some of the recent developments, such as the transformation of SPIO into an activatable probe termed the magnetic relaxation switch.

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Section: Coprecipitationmentioning

confidence: 99%

Section: Coprecipitationmentioning

confidence: 99%

Section: Coprecipitationmentioning

confidence: 99%

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Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging

et al. 2006

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“…24 To increase the magnetic permeability of the ferrofluid, we then boil the Fe 3 O 4 in an aqueous solution of iron nitrate to oxidize the nanoparticles and convert them to maghemite (Fe 2 O 3 ). 25 In this manner, we have been able to produce stable aqueous solutions of up to 5% maghemite by weight. We convert the aqueous ferrofluid to an organic ferrofluid by extraction into neat oleic acid.…”

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confidence: 96%

Magnetically Actuated Nanorod Arrays as Biomimetic Cilia

et al. 2007

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We present a procedure for producing high-aspect-ratio cantilevered micro-and nanorod arrays of a PDMS−ferrofluid composite material. The rods have been produced with diameters ranging from 200 nm to 1 µm and aspect ratios as high as 125. We demonstrate actuation of these superparamagnetic rod arrays with an externally applied magnetic field from a permanent magnet and compare this actuation with a theoretical energy-minimization model. The structures produced by these methods may be useful in microfluidics, photonic, and sensing applications.High-aspect-ratio nanostructures have attracted increasing attention in the nanotechnology community due to their potential applications as sensors 1-3 and actuators 4-7 and the effect of their presence on the surface properties of a material such as adhesion 8-11 and wetting. 12-14 We are interested in producing high-aspect-ratio nanostructures to serve as biomimetic cilia for the purpose of studying the mechanics of nanoscale fluid flow in a ciliated system. To this end, we have produced soft polymeric, actuable nanostructures of the size of biological cilia (∼10 µm in length by ∼200 nm diameter.) High-aspect-ratio polymer rods have been produced with materials with elastic moduli on the order of 100 MPa, 12-13 but these are unsuitable as actuating mechanisms due to their stiffness. Softer materials, such as poly(dimethyl siloxane) (PDMS, E ∼ 2 MPa), have been reported to fail at large aspect ratios due to lateral or ground collapse. 15,16 In addition, in many cases, rodlike microstructures are fabricated via a photolithographic master 15,16 or anodized aluminum oxide (AAO) membrane. 17 However, conventional photolithographic molds involve lengthy or specialized processing to produce large arrays of upright high-aspectratio structures, and AAO membranes impose severe limits on the diameter and spacing of the pores. Furthermore, with soft materials, photolithographic lift-off procedures may lead to structure collapse. Particle track-etched membranes have successfully been used as a template for a variety of materials [18][19][20] and are able to produce high-aspect-ratio structures with variable spacing and diameter. We use polycarbonate track-etched (PCTE) membranes as templates, allowing us to freely select the length and diameter of the rods and the density of the rod array by choosing an appropriate membrane.The high-aspect-ratio and low elastic modulus of our PDMS rods lend them a flexibility that makes them ideally suited to serve as actuators. To this end, we have produced micro-and nanorod arrays using a composite material of PDMS and iron oxide nanoparticles, which results in flexible superparamagnetic rods that may be actuated by applied external magnetic fields. Other groups have devised highaspect-ratio magnetically actuated microstructures via linkedbead chains, 3,7 and Singh, et al. have succeeded in tethering these structures to a substrate. 6 Our templated structures do not necessarily require a liquid medium, have the advantage of being scalable b...

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“…[310] Stable colloidal suspensions are resulted due to adsorption of these polyacids on iron oxide MNPs due to their high coordination on their surfaces via one or two of the carboxylate functionalities. [311] Hydrophilic and negatively charged nanoparticles are consequently resulted due to, at least, one carboxylic acid group exposed to the solvent. [312] However, this method suffers from labile carboxylic functions which can be easily broken by due to elevation of temperature or presence of carboxylic compounds with higher affinities to the surface.…”

Section: Small Organic Molecules (Carboxylates and Organophosphorus Mmentioning

confidence: 99%

Synthesis, Functionalization, and Design of Magnetic Nanoparticles for Theranostic Applications

Mosayebi

Kiyasatfar

Laurent

2017

Adv Healthcare Materials

193

171

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In order to translate nanotechnology into medical practice, magnetic nanoparticles (MNPs) have been presented as a class of non‐invasive nanomaterials for numerous biomedical applications. In particular, MNPs have opened a door for simultaneous diagnosis and brisk treatment of diseases in the form of theranostic agents. This review highlights the recent advances in preparation and utilization of MNPs from the synthesis and functionalization steps to the final design consideration in evading the body immune system for therapeutic and diagnostic applications with addressing the most recent examples of the literature in each section. This study provides a conceptual framework of a wide range of synthetic routes classified mainly as wet chemistry, state‐of‐the‐art microfluidic reactors, and biogenic routes, along with the most popular coating materials to stabilize resultant MNPs. Additionally, key aspects of prolonging the half‐life of MNPs via overcoming the sequential biological barriers are covered through unraveling the biophysical interactions at the bio–nano interface and giving a set of criteria to efficiently modulate MNPs' physicochemical properties. Furthermore, concepts of passive and active targeting for successful cell internalization, by respectively exploiting the unique properties of cancers and novel targeting ligands are described in detail. Finally, this study extensively covers the recent developments in magnetic drug targeting and hyperthermia as therapeutic applications of MNPs. In addition, multi‐modal imaging via fusion of magnetic resonance imaging, and also innovative magnetic particle imaging with other imaging techniques for early diagnosis of diseases are extensively provided.

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Synthesis of very fine maghemite particles

Cited by 474 publications

References 9 publications

Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging

Superparamagnetic Iron Oxide Nanoparticle Probes for Molecular Imaging

Magnetically Actuated Nanorod Arrays as Biomimetic Cilia

Synthesis, Functionalization, and Design of Magnetic Nanoparticles for Theranostic Applications

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