Microbubbles are already approved for use with ultrasound as a diagnostic tool. They’re injected into the blood stream and then exposed to a frequency that causes them to oscillate, which makes them highly visible in ultrasound images. Over the past decade, several research groups have explored a variation of the technology, coating the bubbles with drugs or genes and making them burst, as a new therapeutic method. Grayburn and his colleagues, for example, previously tested this approach as a way to deliver a gene that encourages the growth of new blood vessels in the heart.
However, the approach has a long way to go before it’s a feasible treatment. One key problem is duration. In this study, the protein produced by the new gene was detected for only about three weeks after treatment. “The biggest challenge is to create something that lasts a long time,” says Katherine Ferrara, a biomedical engineer at University of California, Davis. “It’s hard to imagine someone would want to repeat this treatment over and over again.”
Nick Giannoukakis, an immunologist at University of Pittsburgh School of Medicine, who has been working on several experimental therapies for type 1 diabetes, says the approach is interesting, but the key question is “What does this do to diabetes?” He says the delivery system must be shown to reverse or ameliorate diabetes in animals before its potential as a treatment can be judged. Grayburn says that he and his collaborators are working with diabetic animals to answer that question.