Disclosed herein are iron oxide nanoparticles having an iron (II) content in a metastable state that is intermediate the iron (II) content of wstite and magnetite. The disclosed iron oxide nanoparticles exhibit unexpectedly beneficial magnetic properties (e.g., saturation magnetization) resulting from both the size of the nanoparticles and the iron (II) content. Accordingly, the iron oxide nanoparticles are attractive for magnetic imaging applications, such as magnetic particle imaging. Methods of forming the iron oxide nanoparticles are also provided, such methods including a controlled oxidation step wherein a small amount (e.g., 1%) of gaseous oxygen is exposed to wstite nanoparticles for a defined period of time sufficient to partially oxidize the wstite but prevent conversion entirely to magnetite. Finally, methods of using the iron oxide nanoparticles are also provided. Representative methods include magnetic particle imaging, magnetic resonance imaging, and hyperthermia.

The invention relates to novel biocompatible hybrid nanoparticles of very small size, useful in particular for diagnostics and/or therapy.

The purpose of the invention is to offer novel nanoparticles which are useful in particular as contrast agents in imaging (e.g. MRI) and/or in other diagnostic techniques and/or as therapeutic agents, which give better performance than the known nanoparticles of the same type and which combine both a small size (for example less than 20 nm) and a high loading with metals (e.g. rare earths), in particular so as to have, in imaging (e.g. MRI), strong intensification and a correct response (increased relaxivity) at high frequencies.

Thus, the nanoparticles according to the invention, with diameter d.sub.1 between 1 and 20 nm, each comprise a polyorganosiloxane (POS) matrix including gadolinium cations optionally associated with doping cations; a chelating graft C.sup.1 DTPABA (diethylenetriaminepentaacetic acid bisanhydride) bound to the POS matrix by an SiC covalent bond, and present in sufficient quantity to be able to complex all the gadolinium cations; and optionally another functionalizing graft Gf* bound to the POS matrix by an SiC covalent bond (where Gf* can be derived from a hydrophilic compound (PEG); from a compound having an active ingredient PA1; from a targeting compound; from a luminescent compound (fluorescein).

The method for the production of these nanoparticles and the applications thereof in imaging and in therapy also form part of the invention.

The invention described herein relates to sterically stabilized colloidal constructs comprising preformed colloidal particles encapsulated within a polymeric shell. The constructs, which are controllably sized, are nanoparticles comprising hydrophobic elements, electrostatically charged particles with hydrophobic surfaces, hydrophobic inorganic nanostructures, and amphiphilic copolymers with hydrophobic domains and hydrophilic domains. The constructs are made by a process that allows for the simultaneous encapsulation of a preformed colloidal agent as well as a dissolved hydrophobic active within the core of the polymeric nanoparticle. Among the actives incorporated in various embodiments are organic fluorescent dyes, metal nanostructures and superparamagnetic materials for use in combined fluorescence, optical and magnetic resonance imaging applications, and hydrophobic drugs for therapeutic applications.

The present invention relates to a particle composition for use as a contrasting agent in medical imaging such as Magnetic Resonance Imaging (MRI), the particle composition comprising: a metal containing compound comprises at least one metal complexed with at least one metal chelating agent; wherein the metal chelating agent is adapted to bind to one or more protein molecules to thereby allow or enhance visibility of the protein molecules under the medical imaging. The present invention further relates to a diagnostic agent for use in magnetic resonance imaging (MRI) comprising the above described particle composition; and a method of preparing thereof.

The present invention provides nanoparticles including a metallic core having a length along each axis of from 1 to 100 nanometers and a coating disposed on at least part of the surface of the metallic core, wherein the coating comprises polydopamine, along with methods for making and using such nanoparticles. The metallic core may be gold, silver or iron oxide and the polydopamine coating may have other substances bound to it, such as silver, targeting ligands or antibodies, or other therapeutic or imaging contrast agents. The disclosed nanoparticles can be targeted to cells for treating cancer or bacterial infections, and for use in diagnostic imaging.

The present invention relates to nanoparticles for the targeted delivery of antigen to liver cells, in particular, liver sinusoidal endothelial cells (LSEC) and/or Kupffer cells, and for the in vivo generation of regulatory T cells, notably CD4+CD25+FOXP3+ regulatory T cells (Treg). The invention provides pharmaceutical compositions and methods for the prevention and treatment of autoimmune diseases, allergies or other chronic inflammatory conditions, and for generation of regulatory T cells. The nanoparticles used in the invention comprise a) a micelle comprising an amphiphilic polymer rendering the nanoparticle water-soluble, and b) a peptide comprising at least one T cell epitope associated with the outside of the micelle. The micelle may or may not comprise a solid hydrophobic core.

A pH-responsive nanoparticle made of a pH-responsive polymer and a poly(lactic-co-glycolic acid) by self-assembly includes a polyethylene glycol derivative and a R-Histidine derivative that are subjected to a chemical reaction to form the pH-responsive polymer, wherein the surface electric potential of the pH-responsive nanoparticle is 25 to 10 mV, such that when a pH value of the pH-responsive nanoparticle is changed from 7.4 to 5.0 depending upon an external environment, a surface zeta potential of the pH-responsive nanoparticle is converted from negative charge to positive charge.

The invention described herein relates to sterically stabilized colloidal constructs comprising preformed colloidal particles encapsulated within a polymeric shell. The constructs, which are controllably sized, are nanoparticles comprising hydrophobic elements, electrostatically charged particles with hydrophobic surfaces, hydrophobic inorganic nanostructures, and amphiphilic copolymers with hydrophobic domains and hydrophilic domains. The constructs are made by a process that allows for the simultaneous encapsulation of a preformed colloidal agent as well as a dissolved hydrophobic active within the core of the polymeric nanoparticle. Among the actives incorporated in various embodiments are organic fluorescent dyes, metal nanostructures and superparamagnetic materials for use in combined fluorescence, optical and magnetic resonance imaging applications, and hydrophobic drugs for therapeutic applications.

The present invention relates to novel biocompatible imaging particles comprising superparamagnetic iron oxide (SPIO) assembled into submicromiter-sized clusters within a biodegradable polycathecolamine or polyserotonine matrix, their synthesis and use in imaging techniques. These particles overcome the issues of toxicity and unreliable signal of the molecules from the prior art by providing similar contrast to that of the microparticles of iron oxide and rapidly disassemble into isolated SPIO particles once they reach the acidic lysosomal compartment of the MPS cells, thus enabling their digestion. The present invention is thus directed to a particle having a hydrodynamic diameter comprised between 100 nm and 2000 nm, said particle comprising nanoparticles of iron oxide embedded within a matrix of polycathecolamine or polyserotonine, each of said nanoparticles of iron oxide being coated by a polymer which is different from polycathecolamine or polyserotonine

Provided herein are theranostic compositions comprising a Janus nanoparticle-coated microbubble that are useful for imaging (e.g., MRI, or ultrasound) and for delivering a therapeutic or bioactive agent (e.g., nucleic acid(s), drugs, etc), among other uses.