Novel Biocompatible Cobalt Oxide Nanoparticles for Use in Dual Photoacoustic and Magnetic Resonance Imaging

Novel biocompatible poly(ethylene glycol) (PEG)-stabilized CoO nanoparticles have been synthesized. The particles exhibited a near-infrared laser-based photoacoustic signal that was 11 times stronger than that of our previously developed gadolinium oxide nanoparticles. The value of r2/r1 determined by 7 T MRI at room temperature was similar to that of a clinically-used negative MRI contrast agent, Resovist®. These results indicate that the present PEG-stabilized CoO nanoparticles may be highly effective as a bimodal contrast agent for photoacoustic and magnetic resonance imaging.