The invention relates to a ligand compound having a structure A-B-C, wherein (a) A represents a mono- or polyphosphorylated amino acid linked to part B by its amino group to form an amide bond; B represents (i) a carboxylic acid, and (ii) an amino acid or peptidyl group of 2-10 amino acids, an alkyl or alkenyl group comprising 1-26 carbon atoms, a polyethylene glycol group comprising 1-26 carbon atoms or a combination thereof covalently linked to the carboxylic acid; and C represents a hydrophilic group covalently linked to the group of B (ii) or (b) A represents a mono-or polyphosphorylated amino acid linked to B by its carboxylic acid to form an amide bond; B represents an amino acid or peptidyl group of 2-10 amino acids, an amino substituted alkyl or alkenyl group comprising 1-26 carbon atoms, an amino substituted polyethylene glycol group comprising 1-26 carbon atoms or a combination thereof covalently linked to A by their amino group; C represents a hydrophilic group covalently linked to the group of B. The invention further relates to a coated metal nanoparticle such as super paramagnetic iron oxide nanoparticle (SPIONs) coated with a plurality of the aforementioned ligands and a method of producing thereof.

Described herein are compositions having a nanoparticle that is conjugated to at least one bone targeting moiety, wherein the bone targeting moiety is bonded to the nanoparticle by a linker, wherein the nanoparticle contains iron, and wherein the compositions are neutral or pharmaceutically acceptable salts or esters. Also described herein are methods of making these compositions. In one aspect, the nanoparticles serve as contrast agents for magnetic resonance imaging of bone metabolism. The compounds, compositions, and methods described herein can be used in a number of therapeutic applications including diagnosing or monitoring fracture and/or the progress of conditions associated with bone loss, which include, but are not limited to, osteoporosis, Paget's disease, osteolytic tumors, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, osteoarthritis, osteopenia, and hypercalcemia.

Provided are a preparation method of iron oxide-based paramagnetic or pseudo-paramagnetic nanoparticles, iron oxide-based nanoparticles prepared by the same, and a T1 contrast agent including the same. More particularly, the disclosure describes a method for preparation of iron oxide nanoparticles having a extremely small and uniform size of 4 nm or less based on thermal decomposition of iron oleate complex, iron oxide-based paramagnetic or pseudo-paramagnetic nanoparticles prepared by the same, and a T1 contrast agent including iron oxide-based paramagnetic or pseudo-paramagnetic nanoparticles.

Dendronized metallic oxide nanoparticles, a process for preparing the same and their uses.