Enhanced Delivery of AuNPs with Acoustic Cavitation for Photoacoustic Imaging and Photothermal Therapy

Abstract

Among various molecular imaging modalities, ultrasonic imaging and photoacoustic imaging provide unique advantages and also face specific challenges. Ultrasonic molecular imaging, on one hand, is based on mechanical properties of the image object and many unique applications have been developed. With the aid of superior spatial resolution, high frequency ultrasound imaging has also evolved from clinical anatomical imaging to probing of molecular processes on small animals for pre-clinical research. Photoacoustic imaging, on the other hand, combines advantages of both optics and acoustics. Research developments in imaging physics and instrumentation have also found promising biomedical applications. In addition, microbubbles typically used in ultrasonic imaging as the contrast agent present unique mechanical properties and the associated acoustic cavitation has been exploited for therapeutic purposes. Similarly, gold nanoparticles (AuNPs) are found to be an ideal contrast agent for photoacoustic imaging for its bioconjugation capabilities and presumed safety. The efficient light absorption of AuNPs and abilities to tune their optical properties have also led to new photothermal therapy techniques. In the past, we have developed instrumentations that were used for applications of ultrasonic and photoacoustic imaging. New development in combined diagnosis with therapy for both modalities have also been introduced.