Acoustic and optical droplet vaporization for enhanced sonoporation

Sonoporation refers to using ultrasound on microbubbles to induce cavitation so that the permeability of cellular membrane can be enhanced. Enhanced permeability can thus increase the delivery efficiency of therapeutic agents into the cells. In this study, we use gold nanorods (AuNRs) as the therapeutic agent of plasmonic photothermal therapy (PPTT) for tumor treatment. Increased delivery efficiency was demonstrated when we use nanodroplets instead of microbubbles as the carrier of AuNRs. When gold nanodroplets (AuNDs) received combined excitation with ultrasound and laser radiation, droplets vaporization was enhanced. In vitro and in vivo experiments further demonstrated that the enhanced vaporization of AuNDs induced cavitation effects that are three-to-five fold higher than those when using conventional microbubbles. Finally, we also demonstrated that the enhanced cavitation effect leads to significant increase of sonoporation. PPTT efficiency was thus improved and caused severe tumor cell death.