Contrast-enhanced photoacoustic imaging using indocyanine green-containing nanoparticles

Abstract

Contrast agents are attracting a great deal of attention in photoacoustic imaging. Here we introduce an exogenous contrast agent that provides high photoacoustic signal amplitude at the near-infrared wavelength. Our agents consist of Indocyanine green (ICG) and phospholipid-polyethylene glycol (PL-PEG), entitled ICG-PL-PEG nanoparticles. These nanoparticles have overcome numerous limitations of ICG, such as poor aqueous stability, concentration-dependent aggregation and lack of target specificity. ICG-PL-PEG nanoparticles are biocompatible and relatively nontoxic. All the components of ICG-PL-PEG nanoparticles have been approved for human use. Upon pulsed laser irradiation, the nanoparticles are more efficient in producing photoacoustic waves than ICG alone. The results showed that ICG-PL-PEG nanoparticles act as good contrast agents for photoacoustic imaging. These unique ICG-PL-PEG nanoparticles have great potential in clinical applications. © 2014 The Authors.