Bubbles as an imaging agent
Our experiments have shown ultrasound contrast images of ultra-fine bubbles comparable to conventional micro-bubble contrast products. In some cases, ultra-fine bubbles show higher resolution and different behavior in the vascular system simply due to the smaller size of the bubble. Such basic material as albumin, saline or cell culture medium can be transformed into ultra-fine bubble solutions by our newly developed SHSVB system. These fundamental pharmaceutical agents can be visualized by ultrasound in vitro and in vivo. Drugs can be carried by these bubbles functioning as a drug delivery system modality. Thus, the target pharmaceutical material can be easily visualized and monitored within the body by conventional ultrasound imaging devices. We have discovered that irradiation of relatively higher intensity ultrasound can collapse the bubbles to increase local penetration of drugs into cancer cells. This phenomenon referred as sonoporation can be obtained by combining ultra-fine bubble, a pharmaceutical agent and therapeutic ultrasound. The two stage approach of monitoring the location of ultra-fine bubble and then collapsing them to deliver a drug in a specific location is frequently referred as “theranostic ultrasound”. Ultra-fine bubbles combined with various pharmaceutical products may open up a whole new category of theranostic agents.
Two different types of Ringer’s solution ultra-fi ne bubbles generated by our SHSVB system.
Two channel acoustic phantom studies comparing conventional ultrasound contrast agents (left) and ultra-fine bubbles (right).
Comparison of ultrasound images of rat liver before (left) and after (right) intra venous injection of albumin based ultra-fine bubbles.
