Low-Temperature Synthesis of Maghemite Nanoparticles
Materials and Applications for Sensors and Transducers II: Low-Temperature Synthesis of Maghemite Nanoparticles
Synthesis of hematite and maghemite nanotubes and …
The aim of this study was to obtain saccharide (dextran and sucrose)-coated maghemite nanoparticles with antibacterial activity. The polysaccharide-coated maghemite nanoparticles were synthesized by an adapted coprecipitation method. X-ray diffraction (XRD) studies demonstrate that the obtained polysaccharide-coated maghemite nanoparticles can be indexed into the spinel cubic lattice with a lattice parameter of 8.35 Å. The refinement of XRD spectra indicated that no other phases except the maghemite are detectable. The characterization of the polysaccharide-coated maghemite nanoparticles by various techniques is described. The antibacterial activity of these polysaccharide-coated maghemite nanoparticles (NPs) was tested against Pseudomonas aeruginosa 1397, Enterococcus faecalis ATCC 29212, Candida krusei 963, and Escherichia coli ATCC 25922 and was found to be dependent on the polysaccharide type. The antibacterial activity of dextran-coated maghemite was significantly higher than that of sucrose-coated maghemite. The antibacterial studies showed the potential of dextran-coated iron oxide NPs to be used in a wide range of medical infections.
The polysaccharide-coated maghemite prepared under simple adapted chemical method has a particle size considerably smaller than that reported in the literature. The synthesized DIO-NPs and SIO-NPs containing only maghemite in crystalline phase showed spherical well-shaped nanostructure morphology. The MS at 5 K of DIO-NPs and SIO-NPs was approximately 22 emu/g for DIO-NPs and 26 emu/g for SIO-NPs.
Synthesis and Magnetic Properties of Maghemite (γ …
The increasing concentration of nitric acid in synthesis of maghemite nanoparticles will produce smaller size, lower magnetization, better thermal properties, and more stable maghemite nanoparticles.
114. Hyeon T, Lee SS, Park J, Chung Y, Na HB. Synthesis of highly crystalline and monodisperse maghemite nanocrystallites without a size-selection process. 2001;123:12798-801
Regional Centre of Advanced Technologies and Materials
In this paper, maghemite nanoparticles were synthesized by chemical coprecipitation method at various nitric acid concentrations and characterized by a variety of analytical techniques. The stability of maghemite nanoparticles suspension was analyzed by monitoring their particle size distribution using dynamic light scattering (DLS).
The aim of this article is to integrate and extend information from journal literature about antibacterial properties of iron oxide coated with different saccharides. In this work, polysaccharide-coated iron oxide nanoparticles were synthesized by an adapted coprecipitation method. The obtained polysaccharide-coated maghemite nanoparticles were systematically investigated by X-ray diffraction and transmission electron microscopy (TEM). The magnetic hysteresis cycles for the powder samples were also determined at room temperature. The antibacterial activity of these polysaccharide-coated maghemite nanoparticles (PMC-NPs) was tested against P. aeruginosa 1397, Enterococcus faecalis ATCC 29212, Candida krusei 963, and E. coli ATCC 25922.
ThalesNano Nanotechology Inc - Publications
Researche institute in Czech Republic focuses on nanotechnology
Synthesis and characterization of polysaccharide-maghemite composite nanoparticles and their antibacterial properties.
Modifying the Surface Properties of Superparamagnetic …
Galla, Zs.; Beke, F.;Forró, E.;Fülöp, F.; Enantioselective hydrolysis of 3,4-disubstituted β-lactams
Multifunctional Iron Oxide Nanoparticles for …
Hexagonal ferrites: A review of the synthesis, properties and applications of hexaferrite ceramics
A lodestone is a naturally magnetized piece of the mineral magnetite
The research on superparamagnetic iron oxide nanoparticles (SPIONs) has been growing exponentially over the last several years. The field continues to drive in the direction of biomedical applications, especially molecular therapeutics by exploiting the immense qualities of SPIONs . This includes the distinctive controllable properties such as size, shape, magnetism, crystallinity and flexibility in fabricating multifunctional SPIONs with fluorescence, targeting ligands, drugs etc, thanks to the advancements in the syntheses and functionalization techniques developed hitherto. There are some excellent synthetic methods in prior arts on the formation of superparamagnetic magnetite (Fe3O4) and maghemite (γ-Fe2O3) SPIONs, with size control, narrow distribution, water solubility and surface functionalization [-]. The co-precipitation method is a conventional synthetic paradigm where Fe(II) and Fe(III) salts are co-precipitated in a basic solution in the presence of coating materials such as polymer or dextran (or its derivatives). Although the resulted iron oxide nanoparticles (NPs) are larger in size (ca. 100 nm) and partially crystalline, the particles are readily water soluble where their surfaces are directly functionalized. Alternatively, thermal decomposition method using precursors such as Fe(CO)5, Fe(Stearate)2, with high boiling solvents (octadecene, benzyl ether) and surfactants/ligands (oleic acid, oleylamine) can be used to synthesize smaller sized hydrophobic SPIONs (5-10 nm). In order to impart the SPIONs with water solubility for biomedical applications, water-oil microemulsion method can be employed as a reaction medium for coating a hydrophilic ligand (e.g. silica, peptides) on the hydrophobic surface.
They are naturally occurring magnets, which can attract iron
Valero demonstrated the synthesis of carbohydrate-coated SPIONs as MRI nanoprobes . They showed the pH-driven assembly-disassembly natural process that occurred in apoferritin and found it effective for encapsulating maghemite SPIONs of 4 and 6 nm. The SPIONs were further functionalized with two carbohydrates, -acetyl-D-glucosamine and D-mannose vinyl sulfone derivatives. The representative mouse brain images acquired before and 120 s after administration of contrast agents and corresponding regional cerebral blood volume maps (rCBV) maps are shown in Figure . Similar to Endorem, post-contrast images and rCBV maps obtained with Apomaghemite samples depicted very well the space arrangement of cerebral vessels. This study confirmed that Apomaghemite SPIONs could serve as promising contrast agents. Furthermore, the carbohydrate-functionalized Apomaghemite NPs retained their recognition abilities, as demonstrated by the strong affinity with their corresponding carbohydrate-binding lectins.
Superparamagnetic Iron Oxide Nanoparticles as MRI …
Folate-conjugated SPIONs were used for solid tumor targeting in specific magnetic hyperthermia mediators . The folate surface of maghemite NPs could recognize the folate receptor and was proven by folate receptor expressing cell lines or by radio-labeled folic acid in competitive binding experiments. Water-dispersible sugar-coated SPIONs were designed as magnetic fluid hyperthermia heat mediators and 2 negative contrast agents for MRI . SPIONs of ca. 16-18 nm had good transverse relaxivity and large heat release upon application of radio frequency (RF) electromagnetic radiation with amplitude and frequency close to the human tolerance limit. The authors claimed that these particles could be used as an efficient bifunctional targeting system for theranostic applications. Initially, the hydrophobic oleic acid stabilized SPIONs synthesized via thermal decomposition method were made water soluble by the displacement of the stabilizing agents, and by covalent grafting of the carbohydrate derivatives via the phosphonate function.
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