US 9,867,889 B2 · Shape-controlled magnetic nanoparticles as T1 contrast agents for magnetic resonance imaging

Abstract

Methods are provided for the generation of nanostructures suitable for use in magnetic resonance imaging where the nanostructures have at least one dimension of about 2 nm or less. In particular, the methods comprise the selective use of incubation temperatures that result in the controlled removal of ligands from metallic cores to which they are attached, allowing the metallic cores or the precursor moieties to unite to form nanostructures of defined and predictable shapes, but having at least one dimension significantly less that at least one other dimension. Accordingly, the nanostructures of the disclosure may be ultrathin sheets, rods, whiskers and the like, or even structures that are thin and porous resembling rice grains. The temperatures useful in the methods of the disclosure are less than 300° C. and allow for progressive elevation of the incubation temperature. The methods are especially advantageous for synthesizing nanoparticles that may be administered to an animal or human subject for imaging with magnetic resonance. Accordingly, the nanostructures of the disclosure comprise a metallic core, most typically, but not necessarily limited to, a ferrite moiety that can be a ferrous or ferric ion alone or in combination with other metallic elements. However, the methods of the disclosure are also suitable for generating nanostructures with non-ferrous cores such as magnesium or manganese cores.

Claims25

Dependent claims

A method of synthesizing ultrathin nanostructures, wherein the method comprises the steps of:

(a) obtaining a metallic core-ligand complex precursor comprising a metallic moiety and a plurality of ligands attached to said metallic moiety, wherein the plurality of ligands comprises one or more ligands that are more weakly bound and one or more ligands that are more strongly-bound than the more weakly bound ligands, wherein the more weakly bound ligands are characterized in that at an incubation temperature the more weakly bound ligands dissociate and the more strongly bound ligands remain attached;
and
(b) incubating the metallic core-ligand complex precursor mix at the incubation temperature, wherein the incubation temperature is selected from the group of:
from about 100° C. to about 300° C., from about 100° C. to about 200° C., from about 100° C. to about 175° C., from about 100° C. to about 150° C., about 300° C., about 250° C., about 230° C., about 225° C., about 200° C., about 180° C., about 175° C., about 170° C., about 150° C., and about 125° C.,
wherein the incubation temperature is selected to generate a population of ultrathin nanostructures by a process of thermal displacement of some or all of the more weakly-bound ligand(s) from the metallic core,
wherein the ultrathin nanostructures are a nanowhisker, a nanotube, or a nanorice having a diameter of about 4 nm or less and a longest dimension about 10 nm to 500 nm.

3 more elements

Dependencies are inferred from the claim text.

Shape-controlled magnetic nanoparticles as T1 contrast agents for magnetic resonance imaging

Life of this patent

Shape-controlled magnetic nanoparticles as T1 contrast agents for magnetic resonance imaging

Life of this patent

Abstract

Claims25