Ultrasound contrast agents

Microbubbles, developed as ultrasound contrast agents for vascular imaging are valuable theranostic agents for multiple biomedical applications. The utility of these agents can be attributed to their unique response to ultrasound. When exposed to an acoustic pulse, microbubbles can resonate to create a strong acoustic signal that can be used to diagnose conditions including cardiac abnormalities and cancerous lesions. Microbubble resonance can also generate powerful and localized forces capable of creating pores in cell membranes and blood vessels that can be used for targeted drug and gene delivery as well as thromoblysis and opening of the blood brain barrier. Microbubbles have been encapsulated with a variety of materials including lipids, proteins and polymers, these materials have been shown to control a microbubble's acoustic properties as well as its effectiveness as a drug carrier. This review focuses on the progress of microbubbles and the applications of microbubbles as theragnostic agents.