Vascular gene transfer and drug delivery in vitro using low-frequency ultrasound and microbubbles

Abstract

Aim: To determine the effects of ultrasound exposure in combination with a microbubble contrast agent (SonoVue) on the cellular uptake and delivery of drugs/genes into human umbilical vein endothelial cells (HUVECs) as well as their biological effects on migration. Methods: HUVECs in suspension were exposed to pulsed ultrasound with a 10% duty cycle in combination with various concentrations of a microbubble contrast agent (SonoVue) using a digital sonifier at a frequency of 20 kHz and an intensity of 3.77 W/cm 2 on the surface of a horn tip. Cell culture inserts were used to determine the cell migration ability. Results: Exposure to pulsed ultrasound resulted in enhanced green fluorescent protein (EGFP) gene transfection efficiencies ranging from 0.2% to 2%. The transfection efficiency of HUVECs was approximately 3-fold higher in the presence of SonoVue than in its absence at the effective exposure time of 6 s. For drug delivery to HUVECs using ultrasound, the delivery efficiencies of a lowmolecular-weight model drug (TO-PRO ® -1, M W 645.38) were significantly higher when compared to drug delivery without ultrasound, with a maximum efficiency of approximately 34%. However, the delivery efficiencies of a high-molecular-weight model drug (DextranRhodamine B, M W 70 000) were low, with a maximum delivery efficiency of nearly 0.5%, and gene transfection results were similarly poor. The migration ability of HUVECs exposed to ultrasound was also lower than that of the control (no exposure). Conclusion: The use of low-frequency and low-energy ultrasound in combination with microbubbles could be a potent physical method of increasing drug/gene delivery efficiency. This technique is a promising nonviral approach that can be used in cardiovascular disease therapy.

Cavitation-Enhanced Delivery of the Nanomaterial Graphene Oxide-Doxorubicin to Hepatic Tumors in Nude Mice Using 20 kHz Low-Frequency Ultrasound and Microbubbles

“…The use of low-frequency (20 kHz) and low-energy (3.77 W/cm 2 , 10% duty cycle) ultrasound in combination with bubbles (SonoVue) could be a promising physical method of increasing drug/gene delivery efficiency [56]. The dose of MBs injected into the tail vein of the mice was 0.2 mL for each treatment.…”

Polymeric Microbubbles for Ultrasonic Molecular Imaging and Targeted Therapeutics

“…Microbubble contrast agents which were targeted to diseased tissue by using certain chemical constituents in the microbubble shell or by attaching disease-specific ligands such as antibodies to the microbubble [21], play an important role in the ultrasound molecular imaging. On the other hand, there are also many indications that microbubbles could be widely applied as drugdelivery carriers, or to assist in drug/gene delivery [22][23][24][25][26].…”

Low-frequency low-intensity ultrasound with contrast agent for the treatment of subcutaneous tumors in mice

“…If the goal is to produce the inertial cavitation in situ, a sound field with strong focus and low driving frequency (for example 0.5 MHz instead of 2 MHz) is recommended (Wu and Nyborg, 2008). Low-frequency ultrasound is a novel tool for the treatment of several areas such as blood-tumor barrier (Shang et al, 2011;Fan et al, 2011), local gene delivery (Lin et al, 2010;Yang et al, 2010), tumor cell destruction (Lagneaux et al, 2002;Ward et al, 1999;Sergeeva et al, 2001). However, the in vivo environment where low-frequency ultrasound exerts effects is different from that in vitro.…”