Ni-Fe<SUB>2</SUB>O<SUB>4</SUB> Nanoparticles as Contrast Agents for Magnetic Resonance Imaging

Abstract

Reported herein is the synthesis of a dextran coating on nickel ferrite (Ni-Fe2O4) nanoparticles via chemical coprecipitation. The aqueous solution of the synthesized nanoparticles showed good colloidal stability, and no precipitate was observed 20 months after the synthesis. The coated nanoparticles were found to be cylindrical in shape in the TEM images, and showed a uniform size distribution with an average length and diameter of 17 and 4 nm, respectively. The coated particles were evaluated as potential T1 and T2 contrast agents for MRI. The T1 and T2 relaxations of the hydrogen protons in the water molecules in an aqueous solution of dextran-coated Ni-Fe2O4 nanoparticles were studied. It was found that the T1 relaxivity for the aqueous solution of dextran-coated nanoparticles was slightly greater than that of a commercial Gd-DTPA-BMA contrast agent. The T2 relaxivity, however, was almost twice that of the commercial Gd-DTPA-BMA contrast agent. Animal experimentation also demonstrated that the dextran-coated Ni-Fe2O4 nanoparticles are suitable for use as either T1 or T2 contrast agents in MRI.

Relaxivities of hydrogen protons in aqueous solutions of PEG-coated rod-shaped manganese-nickel-ferrite (Mn0.4Ni0.6Fe2O4) nanoparticles

“…Deionized water was used throughout the synthesis of the PEGcoated Mn-Ni-ferrite nanoparticles PEG-coated manganese-nickel-ferrite nanoparticles were formulated by simultaneously coating PEG during the synthesis of the manganese-nickel-ferrite (Mn 0.4 Ni 0.6 Fe 2 O 4 ) nanoparticles via a chemical coprecipitation method. Ahmad et al [8] used the same method for the synthesis of dextran-coated nickel-ferrite nanoparticles. In brief, 3 ml of 0.12-M MnCl 2 ·4H 2 O and 3 ml of 0.18-M NiCl 2 ·4H 2 O aqueous solutions were first mixed with 3 ml of 0.6-M FeCl 3 ·6H 2 O aqueous solution.…”

“…Gadolinium is most commonly used as a commercial MRI contrast agent, but has substantial toxic effects; hence, the chelate of gadolinium is preferred for use as a commercial contrast agent [5,6]. Functionalized superparamagnetic spinel ferrites, such as Fe 3 O 4 [4,7], NiFe 2 O 4 [8], and MnFe 2 O 4 [9] are considered to be the best candidates for use as contrast agents for MRI.…”

“…Mn-Ni-ferrite nanoparticles may be coated with biocompatible substances prior to their use as a MRI contrast agent, substantially reducing their toxicity. Suitable coating materials include polymers such as polyethylene glycol (PEG) [13], chitosan [7], phospholipids [14], and dextran [8]. These polymer-coated magnetic nanoparticles with a magnetic core and a polymer surface coating are known as magnetic polymer nanocomposites [15,16].…”

Carbon-coated iron oxide nanoparticles as contrast agents in magnetic resonance imaging

“…Among these nanostructured materials, carbon-coated metal oxide nanoparticles such as MgO, CaO, ZnO, TiO2, Al 2 O 3 , and Fe 2 O 3 are now extensively studied because of their high application potential [4-9]. Recently, much research interest has been expended on the ferromagnetic iron oxide materials generally used for magnetic data storage as magnetic toners in xerography, and on the ferrofluids, used as contrast agents in magnetic resonance imaging [MRI] [10-13]. …”

Sustained release of anticancer agent phytic acid from its chitosan-coated magnetic nanoparticles for drug-delivery system

“…15 Iron oxide magnetic nanoparticles (MNPs) with general formula Fe 3 O 4 have been widely used for delivery of various drugs owing to some advantages: ease of preparation, superparamagnetic property, [16][17][18] biocompatibility, external control, controllable parameters, 19,20 and hypothermal behavior. 21,22 However, these nanoparticles due to the presence of OH − groups with a large surface area to volume ratio and dipole-dipole attraction without any surface coating will be agglomerated and the size of particles will increase.…”