Hybrid plasmonic magnetic nanoparticles as molecular specific agents for MRI/opticalimaging and photothermal therapy of cancer cells

Abstract

Nanoparticles which consist of a plasmonic layer and an iron oxide moiety could provide apromising platform for development of multimodal imaging and therapy approaches infuture medicine. However, the feasibility of this platform has yet to be fully explored. Inthis study we demonstrated the use of gold-coated iron oxide hybrid nanoparticles forcombined molecular specific MRI/optical imaging and photothermal therapy of cancercells. The gold layer exhibits a surface plasmon resonance that provides opticalcontrast due to light scattering in the visible region and also presents a convenientsurface for conjugating targeting moieties, while the iron oxide cores give strongT2 (spin–spin relaxation time) contrast. The strong optical absorption of the plasmonic goldlayer also makes these nanoparticles a promising agent for photothermal therapy. Wesynthesized hybrid nanoparticles which specifically target epidermal growth factor receptor(EGFR), a common biomarker for many epithelial cancers. We demonstrated molecularspecific MRI and optical imaging in MDA-MB-468 breast cancer cells. Furthermore, weshowed that receptor-mediated aggregation of anti-EGFR hybrid nanoparticles allowsselective destruction of highly proliferative cancer cells using a nanosecond pulsed laser at700 nm wavelength, a significant shift from the peak absorbance of isolated hybridnanoparticles at 532 nm.