Reexamining the Effects of Particle Size and Surface Chemistry on the Magnetic Properties of Iron Oxide Nanocrystals: New Insights into Spin Disorder and Proton Relaxivity

Duan, Hongwei; Kuang, Min; Wang, Xiaoxia; Wang, Y. Andrew; Mao, Hui; Nie, Shuming

doi:10.1021/jp8029083

Cited by 237 publications

(256 citation statements)

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“…Duan et al [74] examined the effect of polymer hydrophobicity on the magnetic properties (relaxivities) of IONPs, and found that the hydrophobic polymers diminished the relaxivity (R 2 ) behavior. In contrast, IONPs with a core size of approximately 10 nm coated with PEI, a hydrophilic charged polymer, presented significantly enhanced relaxivity.…”

Section: Magnetic Resonance Imagingmentioning

confidence: 99%

The design and utility of polymer-stabilized iron-oxide nanoparticles for nanomedicine applications

et al. 2010

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Iron-oxide nanoparticles (IONPs) represent a significant class of inorganic nanomaterial that is contributing to the current revolution in nanomedicine [1][2]. Their unique physical properties, including high surface area to volume ratios and superparamagnetism, confer useful attributes for medical applications such as magnetic resonance imaging (MRI), drug and gene delivery, tissue engineering and bioseparation [3].Two distinct classes of superparamagnetic IONP-based materials are currently used for medical applications: superparamagnetic iron-oxide (SPIO) nanoparticles with a mean particle diameter of 50-100 nm, and ultra-small superparamagnetic iron-oxide (USPIO) nanoparticles with a size below 50 nm. Th ese two classes of IONPs have been studied widely for medical applications, particularly as the next (potential) generation of MRI contrast agents. Th ey are also seen as potential vectors for drug and gene delivery. Th e biodistribution of these nanoparticles can be altered by the application of an external magnetic fi eld; they also have potential applications in hyperthermia therapy as some magnetic particles can heat up under the infl uence of a localized high-frequency magnetic fi eld.Th e intent of this review is to present recent advances in the synthesis of IONPs and their subsequent stabilization in biological fluids using polymers, focusing on the current strategies used to graft polymers onto IONPs surfaces (see Figure 1) and the diff erent types of polymers used. Th e additional properties conferred by the polymers, such as targeting, eff ects on biodistribution and pharmacokinetics, are also discussed, and the main applications of IONPs are reviewed. Synthesis and properties of iron-oxide nanoparticlesSPIO and USPIO nanoparticles are the most extensively studied magnetic nanoparticles for biomedical applications as they are both biocompatible and easy to synthesize. Both are composed of ferrite nanocrystallites of magnetite (Fe 3 O 4 ) or maghemite (Fe 2 O 3 , γ). Over the last ten years, there has been an explosion of interest in these materials and this has been reflected in a large number of recent publications describing the synthesis and modifi cation of hybrid IONPs. In this review, we focus on the polymer modifi cation of the nanoparticles, and provide only minimal information on the inorganic synthesis of IONPs. For more detailed information on IONP synthesis, readers are referred to other reviews [3,4]. The design and utility of polymer-stabilized iron-oxide nanoparticles for nanomedicine applicationsCyrille Boyer 1 * , Michael R. Whittaker 1 , Volga Bulmus 2 , Jingquan Liu 1 and Thomas P. Davis 1 * University of New South Wales, AustraliaOver the past decade, the synthesis of superparamagnetic nanoparticles, especially iron-oxide nanoparticles (IONPs), has been researched intensively for many high-technology applications, including enhanced storage media, biosensing and medical applications. In medicine, IONPs are used as contrast agents in magnetic resonance imaging and in hyperthermia...

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Section: Magnetic Resonance Imagingmentioning

confidence: 99%

The design and utility of polymer-stabilized iron-oxide nanoparticles for nanomedicine applications

et al. 2010

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“…This bonding can mediate the particles' magnetic anisotropy or even enhance their surface spin disorder, thus having an impact in lowering the relaxivity values 66,67 .…”

Section: C5 the Cncs Relaxivities And Their Relevance For Other Ferrmentioning

confidence: 99%

Colloidal assemblies of oriented maghemite nanocrystals and their NMR relaxometric properties

et al. 2014

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“…Some recent reports have shown that the MRI contrast, e.g., the signal drop with T 2 weighted imaging, can be significantly enhanced by clustered IONPs [12,[27][28][29][30]. However, the samples of single or clustered IONPs employed were coated with different materials which may have affected their magnetic properties [12,28,31]. Our measurements of transverse T 2 relaxation times showed that the clustered IONPs exhibit an approximate 3.7-fold increase in the transverse relaxation rate R 2 (1/T 2 , s -1 ) when compared to that of single core IONPs coated with the same copolymer, providing higher MRI contrast at the same Fe concentration (Fig.…”

Section: Resultsmentioning

confidence: 99%

Preparation and control of the formation of single core and clustered nanoparticles for biomedical applications using a versatile amphiphilic diblock copolymer

et al. 2010

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We report the application of a versatile diblock copolymer, poly(ethylene oxide)-b-poly(γ-methacryloxypropyl trimethoxysilane) (PEO-b-PγMPS), to prepare nanocrystals such as iron oxide nanoparticles or quantum dots, with either a single core or multi-core cluster, for biomedical applications. This amphiphilic copolymer comprises both a hydrophilic PEO segment and a hydrophobic segment with a "surface anchoring moiety" (the silane group) which can interact effectively with the hydrophobic nanocrystals through ligand exchange. One of the unique features of this work is that we can control the formation of either single core nanoparticles or multi-core nanoclusters by simply varying the conditions of ligand exchange and aging of the mixture of block copolymer and nanoparticles without needing to change the copolymer. The morphologies of the resulting single core nanoparticles or multi-core nanoclusters were confirmed by dynamic light scattering and transmission electron microscopy. The clustered nanoparticles exhibit enhanced physicochemical properties that are beyond those expected from a simple accumulation of individual nanoparticles. Additionally, the hybrid nanoparticles containing both magnetic iron oxide nanoparticles and optical quantum dots obtained using our strategy provide have combined magnetic and optical functionalities that allow for potential new and expanded biomedical applications, as demonstrated by their use for magnetic resonance imaging and biomarker-targeted cell imaging.

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Reexamining the Effects of Particle Size and Surface Chemistry on the Magnetic Properties of Iron Oxide Nanocrystals: New Insights into Spin Disorder and Proton Relaxivity

Cited by 237 publications

References 25 publications

The design and utility of polymer-stabilized iron-oxide nanoparticles for nanomedicine applications

The design and utility of polymer-stabilized iron-oxide nanoparticles for nanomedicine applications

Colloidal assemblies of oriented maghemite nanocrystals and their NMR relaxometric properties

Preparation and control of the formation of single core and clustered nanoparticles for biomedical applications using a versatile amphiphilic diblock copolymer

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