Intracellular Acoustic Droplet Vaporization in a Single Peritoneal Macrophage for Drug Delivery Applications

Abstract

This study investigated the acoustic droplet vaporization (ADV) of perfluoropentane (PFP) droplets in single droplet-loaded macrophages (DLMs) by insonation with single three-cycle ultrasound pulses. Transient responses of intracellular ADV within a single DLM were observed with synchronous high-speed photography and cavitation detection. 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 at the onset of vaporization may facilitate gas embolotherapy and ultrasound imaging. Macrophages can be potential carriers transporting PFP droplets to avascular and hypoxic regions in tumors for ultrasound-controlled drug release and ADV-based tumor therapies.

Phase-transition Perfluorocarbon Nanoparticles for Ultrasound Molecular Imaging and Therapy

“…As a result, the gas phase can rapidly formed by the "driving force" if the time window is long enough (low ultrasonic frequency) or the internal pressure is small enough (high acoustic amplitude). These process has been observed by several reports [50][51][52].…”

Magnetic nanoparticle-promoted droplet vaporization for in vivo stimuli-responsive cancer theranostics

“…A new concept of MDV using a.c. magnetic field as the triggering source for cancer theranostics can effectively overcome the drawbacks of traditional ADV and ODV because there is no gas/bone influence of ultrasound or penetration depth limitations of a laser. [18][19][20]44,45 The stimuli-responsive vaporization process to produce microbubbles can substantially enhance ultrasound imaging, which can be further used for ultrasonography-guided magnetic hyperthermia of cancer. Importantly, the trigger by the a.c. magnetic field does not damage normal tissues where only small amount of PFH-HIONs are present.…”

“…Typically, ADV employs acoustic waves to evaporate the liquid droplets. [18][19][20] However, because ultrasound is easily and substantially influenced by gas or bone, the use of ADV is restricted in vascular imaging, cancer detection and drug delivery. ODV uses a laser as the excitation source to induce the vaporization of liquid droplets.…”

Notice of Removal: Optically and acoustically triggerable sub-micron phase-change contrast agents for enhanced photoacoustic and ultrasound imaging

“…perfluorocarbons were used in these studies, i.e., perfluoropentane (b.p. 29 C) [10][11][12]17,18] and perfluorohexane (b.p. 56 C) [13,14,19].…”