Magnetic iron-oxide nanoparticles coated in biocompatible milk protein for imaging contrast enhancement and drug delivery.
- Contains a biocompatible coating.
- Shows increased water solubility and stability in solution.
- Protein coating layer facilitates a high efficiency contrast enhancement for magnetic resonance imaging.
- Can be conjugated to targeting molecules which allows for site-specific or tissue specific delivery and imaging.
Iron oxide nanoparticles (IONPs) are iron oxide particles with diameters between 5-100 nm that display unique magnetic and MRI contrast enhancing characteristics. Because of these unique features, IONPs can be used as contrast agents for MRI examinations to enhance MR images or to detect particular disease cells or tissues by the addition of a targeting molecule. The market for highly sensitive and disease specific MRI contrast agents is rapidly growing with the emphasis on personalized medicine and early diagnosis. It is expected to continue to grow as new targeted agents become approved particularly in the cardiovascular and oncology spaces. When combined with delivery of drugs, these targeted agents can be used to facilitate efficiency of drug delivery and image-guided drug delivery.
IONP based contrast agents provide a different contrast enhancing form comparing to traditionally used gadolinium based MRI contrast agent and are in being used already in certain diagnostic imaging applications. To apply the agents to other imaging application and disease detection, however, new IONP contrast agents are needed. Distinct challenges to the clinical use of IONPs and adoption include obtaining water solubility and ensuring nanoparticle stability in physiological condition. Researchers have attempted to improve solubility by creating biocompatible coatings (both synthetic & natural); however coating IONPs with synthetic materials may introduce concerns in toxicity and biocompatibility. These coatings may also provide other functions, such as reactivity for conjugation to other molecules or the encapsulation of drugs. Emory researchers have addressed this challenge by creating a casein-coated IONP for use in targeted imaging or targeted drug delivery. Casein is a phosphoprotein that is present in mammalian milk and used extensively in the food industry as a binding agent. This coating greatly increases solubility of the IONPs with more than two fold improvement in MRI contrast enhancing effect comparing to the same IONP coated with synthetic polymers. Additionally a highly efficient and robust process for manufacturing these nanoparticles was created for coating IONPs comparing to harsh chemical synthesis with many chemical reagents. Targeting molecules or chemotherapeutic agents (both hydrophilic or hydrophobic) can be attached to the casein-coated IONP to image particular tissues or to imaging of drug delivery process concurrently in vivo.
Casein-coated IONPs have been used for targeted MRI imaging studies and drug delivery in mice.