Microbubbles - A Promising Ultrasound Tool for Novel Drug Delivery System: A Review

Microbubbles are emerging as important contrast agents for imaging and carriers for targeted drug delivery. Microbubbles designate air or gas filled microspheres suspended in a liquid carrier phase which generally results from the introduction of air or gas. The liquid phase contains surfactants to control the surface properties as well as stability of the bubble. The microbubbles have an average size less than that of red blood cells, so they are capable of penetrating even into the small blood capillaries and releasing drug and genes under the action of ultrasound field after reaching the specific area of interest. Microbubbles in general have a wide variety of applications. However in the biomedical field these are primarily used as diagnostic agents in combination with ultrasound for molecular imaging of various organs and even tumors. These are also proposed for drug and gene delivery to targeted regions in combination with various ligands. Herein, article includes composition, properties, method of preparation, mechanism and application of microbubbles and review recent results on their performance under various imaging and drug delivery scenarios.