A magnetic nanoparticle includes a magnetic core and a superparamagnetic outer shell, in which the outer shell enhances magnetic properties of the nanoparticle. The enhanced magnetic properties of the magnetic nanoparticle allow for highly sensitive detection as well as diminished non-specific aggregation of nanoparticles.

The disclosure provides nanoemulsion compositions and methods of making and using thereof to deliver a bioactive agent such as a nucleic acid to a subject. The nanoemulsion composition comprises a hydrophobic core based on inorganic nanoparticles in a lipid nanoparticle that allows imaging as well as delivering nucleic acids. Methods of using these particles for treatment and vaccination are also provided.

A photothermal magnetic resonance imaging enhancement agent includes composite nanoparticles. The composite nanoparticle includes an inner layer of a dielectric material with a porous substrate having pores, an inner layer with a core, magnetically responsive nanoparticles disposed on the porous substrate, and an outer layer of a metallic material around the inner layer and the magnetically responsive nanoparticles. A method of making a photothermal magnetic resonance imaging enhancement agent includes synthesizing a dielectric substrate, baking the dielectric substrate to generate pores, synthesizing magnetically responsive nanoparticles, loading the magnetically responsive nanoparticles into the pores, attaching linker molecules to the dielectric core, attaching a metal nanoparticle to at least a portion of the linker molecules, reducing additional metal onto the metal nanoparticles to form an outer layer disposed on the dielectric inner layer, and selecting reducing a condition such that the outer layer has a controllable thickness forming a composite nanoparticle.

The disclosure provides nanoemulsion compositions and methods of making and using thereof to deliver a bioactive agent such as a nucleic acid to a subject. The nanoemulsion composition comprises a hydrophobic core based on inorganic nanoparticles in a lipid nanoparticle that allows imaging as well as delivering nucleic acids. Methods of using these particles for treatment and vaccination are also provided.

A core-shell nanoparticle having a cleaned nitrogen-vacancy nanodiamond (NVND) core surrounded by an upconversion nanoparticle (UCNP) shell, wherein the cleaned nitrogen-vacancy nanodiamond (NVND) core comprises a cleaned nitrogen-vacancy nanodiamond, wherein the UCNP shell comprises an upconversion nanoparticle (UCNP), wherein the UCNP comprises lithium yttrium fluoride (LiYF.sub.4) doped with a lanthanide ion combination, wherein the lanthanide ion combination comprises a M1 ion and a M2 ion, wherein M1 is ytterbium (Yb) or neodymium (Nd) and M2 is erbium (Er), thulium (Tm) or holmium (Ho), and wherein the core-shell nanoparticle emits a red-emission upon a near-infrared (NIR) excitation is disclosed. Integration of cleaned NVNDs with UNCPs for enhancing optical manipulation and enabling efficient energy transfer for applications in biological imaging, quantum sensing and laser cooling is disclosed.

A ferrite nano-composites with synergistic enhancement of liver specificity and preparation method and application thereof, wherein the ferrite nano-composites have both manganese ions and ethoxybenzyl group, and the molar percentage of ethoxybenzyl group to manganese ions is 25-60%. The molar percentages of manganese and ferric ions in the ferrite nanoparticles are 40-80%, and the ferrite nano-composites with manganese ions and ethoxybenzyl groups on the surface are in the particle size range of 0.2-5 nm, with preferred particle size range of 2-4 nm. With the preparation method and the application for magnetic resonance T1 imaging, the ferrite nano-composites enhance hepatocyte specificity due to the synergistic effect of manganese ions and ethoxybenzyl groups, thus achieving enhanced T1 imaging of the liver with high specificity in magnetic resonance imaging.