Synthesis and acoustic conversion of perfluorocarbon nanodroplets containing solid nanoparticles within their liquid cores

Phase change contrast agents (PCCAs) are fluorocarbon liquid droplets that convert into microbubbles when exposed to high acoustic pressures. Given their small size, PCCAs can exit leaky blood vessels and provide exogenous contrast outside of the vascular system, thereby circumventing one of the primary limitations of microbubbles. However, a limitation of PCCAs is the high acoustic pressure required for conversion to gaseous phase, which may restrict their use as a diagnostic imaging agent. The incorporation of solid nanoparticles into the liquid perfluorocarbon phase has been suggested as a means to reduce the pressures required to convert PCCAs, however, this has not been confirmed through rigorous empirical observation. In this work, we sought to determine whether the presence of solid nanoparticles contained within the liquid perfluorocarbon core of PCCAs effects the pressure required for acoustic conversion into a gaseous microbubble.