Therapeutic applications of microbubbles

Abstract

While microbubbles have been developed for diagnosis as ultrasound contrast agents, the greatest potential of these agents may lie in therapy. Microbubbles have extensive applications for treating vascular thrombosis, drug and gene delivery. Targeted microbubbles containing ligands for cell or site-specific recognition have been developed. These agents function like ‘‘smart bubbles’’ to home in on their targets. One such agent, MRX-408, a microbubble bearing targeting ligands directed to the activated receptor of platelets has undergone extensive pre-clinical testing. Recent studies comparing Sonothrombolysis with MRX-408 and nontargeted microbubbles show significantly more clot lysis with targeted as compared to nontargeted microbubbles. The targeted bubbles effectively concentrate cavitation nuclei within the clot. Additional targeted microbubbles for drug and gene delivery are also under development.

Preparation and characterization of dextran nanobubbles for oxygen delivery

“…Dextrose albumin microbubbles for oxygen and nitrogen delivery have been formulated (Porter et al, 1998) for use as contrast agents. Oxygen-enriched lipid-coated perfluorocarbon microbubbles have been prepared for oxygen delivery; these oxygen-enriched microbubbles were tested in a model of anemic rats (Unger et al, 2002, Unger et al, 2004 and maintained the rat's survival at very low hematocrit levels.…”

Acoustically-active microbubbles conjugated to liposomes: Characterization of a proposed drug delivery vehicle

“…In addition to the use of microbubbles with ultrasound for molecular imaging approaches, combining microbubbles and therapeutics has recently been considered [13][14][15][16][17]. The thin microbubble shell and gas core each have limited drug-carrying capacity, and therefore, do not yield an efficient therapeutic delivery vehicle.…”

Cavitation Threshold of Microbubbles in Gel Tunnels by Focused Ultrasound

“…Microbubbles loaded with a bioactive substance can be destroyed in a target organ or tissue, thus allowing for the local delivery of therapeutics (Blomley et al 2001). They can also be targeted to a specific tissue by incorporating protein ligands on their surface (Unger et al 2002).…”