Nanoparticles for photoacoustic imaging of vasculature

Photoacoustic imaging (PAI) is a multi-scale, multi-contrast biomedical imaging modality that can provide anatomical, functional, metabolic, and molecular information about tissue. PAI offers up to submicron resolution and several centimeters penetration depth, employing various endogenous or exogenous contrasts. In particular, because nanoparticles strongly absorb near infrared light, they enable high-contrast PAI with improved detection sensitivity at depths. In this chapter, we review the use of nanoparticles to enhance the performance of PAI in a wide range of biomedical applications, in particular in imaging vasculature. By using engineered nanoparticles with different structures and functions, PAI can target specific molecules in disease associated endothelial cells. By manipulating nanoparticles with light or ultrasound, PAI can also guide therapy. Overall, nanoparticle-enhanced PAI shows promising potential for high-sensitivity, deep-tissue imaging, especially for vasculature imaging.