Nanoparticle-enhanced photoacoustic diagnosis and photothermal treatment of small-animal early-stage liver cancer

Synergy of light and sound, such as photoacoustic imaging, has demonstrated promising potentials in advancing the state-of-the-art of biomedical imaging by ultrasonically detecting the absorption of light, no matter the light is diffusive or not. As a result, optical contrast can be revealed with ultrasound or sub-ultrasound spatial resolution, which can be exploited to map sensitively the early tissue changes associated with the onset and development of early-stage diseases. The sources of photoacoustic emissions, however, could be very complicated within living biological tissue, as many tissue constituents may absorb light and generate heat to emit the ultrasonic waves, which considerably reduces the contrast between the target and the background. Therefore, exogenous agents, such as nanoparticles, that have absorption spectrum distinctive from that of background tissues have been widely used in the field to enhance the photoacoustic detection contrast and sensitivity at selected optical wavelengths. This talk summarizes our recent efforts in this direction that have explored various nanoparticles for more robust and more sensitive diagnosis and treatment of early-stage liver cancer based on photoacoustic imaging and photothermal effect. While the studies are based on merely small animal models, they may inspire further explorations towards preclinical and clinical trials.