Improved Transversal Relaxivity for Highly Crystalline Nanoparticles of Pure γ‐Fe₂O₃ Phase

Abstract

Pure and highly crystalline γ-Fe2O3 nanocrystals (NCs) are obtained when hydrolysis and oxidation of a Fe(II) organometallic precursor are performed in successive steps. Their synthesis in pure alkylamine leads to NCs of about 6 nm. In aqueous solutions of poly(vinyl)pyrrolidone, such pristine NCs form aggregates of about 150 nm that exhibit a high transversal relaxivity (r2 =466 mM(-1) s(-1)) about four times higher than that of a commercial Feridex magnetic resonance imaging (MRI) contrast agent. Consequently, they provide a significant decrease in the NMR signal at very short echo time (8 ms), which is of paramount importance in clinical practice because of the reduced duration of MRI measurements.

Effect of nanoparticles on spontaneous Ouzo emulsification

“…The iron oxide (-Fe2O3) NP were synthesized following a reported procedure with slight modifications. 32 Briefly, the iron oxide NP are obtained via hydrolysis of an organometallic Fe(II) precursor in the presence of a stabilizing ligand (here 2 eq. of octylamine and 1 eq.…”

Hydrolysis of organometallic and metal–amide precursors: synthesis routes to oxo-bridged heterometallic complexes, metal-oxo clusters and metal oxide nanoparticles

“…205 Metal oxide NPs produced by hydrolysis of reactive precursors have found a range of applications including the pseudo-homogeneous catalytic reduction of CO2 to MeOH (ZnO and Cu NPs); 173,202,206,207 polymeric antibacterial surfaces (ZnO); 208, 209 photocatalysts (ZnO); 183, 210 gas sensors (ZnO, 211 SnO 194,195 , CuO 172 ); photoconductive UV detectors (ZnO); 212 and MRI contrast agents (-Fe2O3). 167 The ability to control size, morphology, surface chemistry and ligand coverage has proved very valuable in producing NPs for these applications.…”

“…166 Furthermore, employing a stepwise process, where oxidation is undertaken subsequently to hydrolysis, results in higher-quality superparamagnetic Fe2O3 NPs, indicating the importance of controlling both hydrolysis and oxidation pathways. 167 If the absence of oxygen is required, water must be added to the precursor solution. A water miscible solvent such as acetone or THF may be used as a medium to disperse the required water and is useful for mixing moisture into non-polar solvents such as hexane or toluene.…”

Dynamics of Superparamagnetic Iron Oxide Nanoparticles with Various Polymeric Coatings

“…Recently, nanotechnology has been receiving a great deal of interest in many branches of science and technology, especially in medicine and biotechnology [1]. Advances in the biomedical sector are strongly influenced by nanoparticle research due to a wide range of possible applications; e.g., in drug delivery [2,3], cancer detection [4], tissue regeneration [5], magnetic resonance imaging (MRI) [6,7] or magnetic fluid hyperthermia (MFH) [8,9]. Among the various types of nanoparticles, those with magnetic functionality are attracting a great deal of interest.…”