JitKang Lim — 2006-07 Fellow
This project will develop and characterize new bifunctional iron oxide (magnetite)/gold composite nanoparticles that combine the advantages of each constituent material for biomedical applications. Magnetite cores enable magnetophoretic sorting of cells and/or biomolecules. Gold shells exhibit localized surface plasmon resonance that enables optical detection of single nanoparticles below the diffraction limit without fluorophores and also detects changes in local dielectric properties due to either nanoparticle packing on cell surfaces or adsorption of biomolecules. The surface plasmon resonance eliminates the need for immunofluorescence labeling steps that have been noted as sources of large variability in magnetic cell sorting. The nanoparticles will be smaller and less polydisperse in size than existing particles described in the magnetic separations literature.
Two immediate applications are envisioned where the combined magnetic and optical properties are advantageous: improving the reliability of magnetically sorting cells on the basis of surface marker expression level, and providing the ability to directly image single magnetic nanoparticles in a microfluidic magnetic field gradient device for biomolecular separations.