Silica Coated Iron/Iron Oxide Nanoparticles as a Nano-Platform for T2 Weighted Magnetic Resonance Imaging

Abstract

The growing concern over the toxicity of Gd-based contrast agents used in magnetic resonance imaging (MRI) motivates the search for less toxic and more effective alternatives. Among these alternatives, iron–iron oxide (Fe@FeOx) core-shell architectures have been long recognized as promising MRI contrast agents while limited information on their engineering is available. Here we report the synthesis of 10 nm large Fe@FeOx nanoparticles, their coating with a 11 nm thick layer of dense silica and functionalization by 5 kDa PEG chains to improve their biocompatibility. The nanomaterials obtained have been characterized by a set of complementary techniques such as infra-red and nuclear magnetic resonance spectroscopies, transmission electron microscopy, dynamic light scattering and zetametry, and magnetometry. They display hydrodynamic diameters in the 100 nm range, zetapotential values around −30 mV, and magnetization values higher than the reference contrast agent RESOVIST®. They display no cytotoxicity against 1BR3G and HCT116 cell lines and no hemolytic activity against human red blood cells. Their nuclear magnetic relaxation dispersion (NMRD) profiles are typical for nanomaterials of this size and magnetization. They display high r2 relaxivity values and low r1 leading to enhanced r2/r1 ratios in comparison with RESOVIST®. All these data make them promising contrast agents to detect early stage tumors.

Surface engineering of silica nanoparticles with a gadolinium–PCTA complex for efficient T1-weighted MRI contrast agents

“…The synthesis of NPSiO 2 was carried out following the procedure published in a previous publication 1 . Depending on the reaction time two sets of NPs could be obtained.…”

“…NH 2 modified silica NPs (NPSiO 2 -NH 2 ) : protocol and TEM analysis 4. 1 H and 13 C NMR spectra of compounds 10 and 12 5. Mass spectra of Gd-COOH and Gd-OH 6.…”

Plasmon-Enhanced Controlled Drug Release from Ag-PMA Capsules

“…Recently, the core/shell nanostructures, consisting of a polymeric core and a silica shell, have been considered promising thermal-responsivity drug carriers, thanks to their unique optical responsitivity, and a chemically modifiable surface. The surface of silica is covered by silanol groups, which can react with various chemical agents to conjugate with several kinds of biomolecules and specific ligands [22,23]. Thus, the development of novel hybrid systems, arising from combinations of materials different in nature [24,25] and characterized by unique biological properties, represents a tremendously interesting field in biomedical research [26][27][28].…”

A Novel Class of 1H‐MRI Contrast Agents Based on the Relaxation Enhancement Induced on Water Protons by 14N‐Containing Imidazole Moieties

“…[5] Although clinical consequences have been reported only in the case of patients with impaired renal function, these observations bring ag rowing concern about the use of GBCAs. [6][7][8] Thus,p robe developers are urgently challenged to find alternatives to GBCAs; [9][10][11] the problems raised by GBCAs suggest addressing routes that do not involve metal complexes.M eanwhile,r esearchers attention is also devoted to the search for innovative solutions that could allow in vivo applications that would not have been possible using GBCAs.…”