Nanoparticles as Contrast Agents for Optoacoustic Imaging

Abstract

Nanoparticles have been designed and applied as contrast-enhancing agents in various optical imaging techniques, such as optical coherence tomography, fluorescence imaging, optical reflectance microscopy and recently, optoacoustic imaging. We review applications of nanoparticle based contrast agents in the rapidly growing field of optoacoustic imaging and sensing. We describe biodegradable optoacoustic contrast agents such as nanoparticles containing hemoglobin, melanin and organic dyes in view of their biocompatibility and minimal toxicity. Particular focus is given to metal nanoparticles including hollow gold nanospheres, nanocages and nanorods that possess strong optical absorption due to surface plasmon resonance. Advantages of optoacoustic imaging enhanced with nanoparticle based contrast agents are demonstrated when compared with other optical techniques.