Described herein are nanoparticle compositions that can be used to target specific regions of the blood brain barrier (BBB). Such nanoparticle compositions can be used to deliver therapeutics to or across the BBB or to image the BBB or the permeability thereof.

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.

Provided herein is a nanoparticle comprising a metal core and a polymer shell coating the metal core useful as a magnetic resonance contrast agent.

Described are coated iron oxide nanorods (IONRs) containing an iron oxide core and a coating surrounding the core, and pharmaceutical compositions containing these coated IONRs. The iron oxide core of the coated IONRs has strong magnetic property, i.e., a magnetic flux density of at least 10 emu/g, induced using 1 T magnetizing field strength, at room temperature. The coating of the coated IONRs can be formed by a polymer, such as an amphiphilic polymer. The coated IONRs are stable in an aqueous medium for at least 30 mins, at room temperature, while maintain the superior magnetic property of the core, achieving a separation efficiency of at least 80% within only 1 min of magnet time. Optionally, the coated IONRs contain one or more active agents embedded in the coating of the coated IONRs, for systemic or local delivery.

The invention relates to highly fluorescent metal oxide nanoparticles to which biomolecules and other compounds can be chemically linked to form biocompatible, stable optical imaging agents for in vitro and in vivo applications. The fluorescent metal oxide nanoparticles may also be used for magnetic resonance imaging (MRI), thus providing a multi modality imaging agent.

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.

Multimodal optical and magnetic resonance imaging methods based on the use of persistent luminescence nanoparticles. Use of mesoporous persistent luminescence <<core-shell>> complexes for theranostic applications.

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.

Disclosed herein are nanoconstructs comprising a nanoparticle, coated with additional agents such as cationic polymers, stabilizers, targeting molecules, labels, oligonucleotides and small molecules. These constructs may be used to deliver compounds to treat solid tumors and to diagnose cancer and other diseases. Further disclosed are methods of making such compounds and use of such compounds to treat or diagnose human disease.

Composition and method for surface-functionalized SPION-based agents. Such agents can provide highly pH-sensitive MRI contrast in tissue.