Modern medicine has an elegant new tool: the bubble. It sounds crazy, but if you take an oily solution, froth it into a bunch of tiny bubbles, and inject those into your bloodstream, when you hit them with ultrasound a nearly perfect image of your internal organs will bounce back. And that's just the beginning. "I expect microbubbles to revolutionize medical treatment across a wide array of fields, from gene therapy to chemotherapy," says Mark Borden, a biomedical engineer at UC Davis. Microbubbles first catapulted to prominence in the mid-'90s, when the FDA cleared them for use in imaging applications. They quickly became a cheap alternative to expensive scans – all that's needed is a shot and a portable ultrasound machine. Plus, the technique is fast; microbubbles can be imaged in minutes, while CTs and MRIs take hours.
Since then, researchers have demonstrated that little bubbles have another use: delivering pharmaceutical payloads inside the body. Bubbles coated with specific molecules will selectively bind to certain cellular receptors. Once they're attached, a strong burst of ultrasound is all that's needed to pop the bubbles and free what's inside. Delivering drugs directly to a tumor this way would allow for smaller doses – no more bombarding the whole body with radioactive material – thereby radically reducing side effects. Gene therapy, which treats genetic diseases by using viruses to deliver DNA, could also be safer if the material were administered via microbubble. Both techniques are being tested on animals.
The most impressive accomplishment on the microbubble's résumé, however, may be its ability to get drugs across the blood-brain barrier. Small molecules like alcohol can make it into the gray matter, but anything larger is typically kept out – a trait that protects us but has severely limited the treatment options for neurological diseases like Alzheimer's. Over the past few years, scientists at UC Davis have been working to show that microbubbles can be "pushed" to the barrier and then exploded, opening up small pores through which drugs can pass. The result may eventually give doctors a much larger palette of drugs for brain diseases. No wonder champagne goes straight to your head.
