Targeting drugs to pass through the blood-brain barrier and reach a particular region of the brain is a difficult task. One possible solution, using ultrasound, is described this week over at MIT’s Technology Review:
Focused ultrasound works by directing sound waves toward a point in space. Individually, the waves are not powerful enough to affect the tissue, but when targeted, their collective intensity is much greater. High-intensity focused ultrasound (HIFU), which applies more intense sound waves, has been used to destroy tumors through heating, a process known as ablation.
When targeting the brain, though, Konofagou’s team used much lower-intensity levels, similar to those applied in diagnostic ultrasound, the technology used during a pregnancy sonogram. While researchers don’t know exactly how this technique is able to open the barrier, they say it’s not through heating.
Unlike tumor ablation –and this distinction is key — Konofagou’s technique appears to be reversible. Using an MRI contrast agent, she was able to show that the barrier closed up after about four hours. This is important, explains Pierre Mourad, principal physicist and research associate professor in the department of neurological surgery at the University of Washington, because “the longer the blood-brain barrier is open, the longer you let nasty stuff in the brain.”
More from Konofagou’s recent ASA talk in Providence, RI…
