Ultrasound-Induced Stable and Inertial Cavitation of Magnetic Nanoparticles for Drug Delivery Applications

Drug-loaded magnetic nanoparticles (MNPs) accumulated by an external magnetic field already showed their efficacy in localized tumor treatment in animal studies. Furthermore, specific MNPs are sonosensitive, enabling them to generate inertial cavitation when exposed to a focused ultrasound field. This can be used for controlling drug release, as well as for particle detection and mapping. In addition to inertial cavitation, stable cavitation is also a part of the cavitation process, which has not yet been evaluated on MNPs. While stable cavitation is less harmful to surrounding tissue compared to inertial cavitation, it also contributes to enhanced tumor perfusion. Hence, an optimal strategy could involve inducing inertial cavitation only within the tumor region for drug release and mapping, while employing stable cavitation outside the tumor to enhance perfusion. This study aims to investigate stable cavitation mediated by MNPs for the first time, while examining their overall cavitation behavior.