Yanqing Zhong, Geoffrey P. Luke
Drug delivery can be improved by incorporating the therapeutic molecules inside nano-sized carriers. This can enable controlled release of the drugs at the site of interest, thus minimizing off-target effects. Recent advances in nanotechnology have led to the development of "smart" nanoparticles, which can release their cargo in response to an external stimulus. Ultrasound is a promising external stimulus, because it is able to safely provide mechanical energy in a tightly focused region deep in soft tissue. In this region, the ultrasound provides pressure changes, heating, and/or shear forces that can facilitate drug release from the nanoparticles. In this review, we highlight recent advances in smart nanoparticles and describe how ultrasound could be used to achieve real-time on-demand drug delivery in situ. We also identify promising areas of future research that could lead to impactful drug delivery strategies.