Acoustically-triggered droplet vaporization in macrophages for hypoxic-tumor therapy

This study investigated the feasibility of inducing the vaporization of perfluoropentane (PFP) droplets in single drop-let-loaded macrophages (DLMs) by insonation with single three-cycle ultrasound pulses. High speed photography and cavitation detection were simultaneously conducted to observe transient responses of intracellular ADV within a single DLM. Ultrasound B-mode imaging was further applied to demonstrate the contrast enhancement of ADV-generated bubbles from a group of DLMs. The PFP droplets incorporated in a DLM can be liberated from the cell body after being vaporized into gas bubbles. Inertial cavitation can be simultaneously induced at the same time that bubbles appear. The coalescence of bubbles occurring after the onset of vaporization may facilitate vascular occlusion and ultrasound imaging. The macrophages can be potential carriers transporting PFP droplets to avascular and hypoxic regions in tumors for controlled drug release and occlusion therapy.