The blood-brain barrier is an important defense mechanism that prevents infections and contamination within the brain. It is also responsible for making it extremely difficult to get therapeutic drugs, including chemo agents, into the brain. Now researchers at Washington University in St. Louis have developed an innovative method for pushing drugs across the blood-brain barrier.
The technique, called cavitation dose painting, relies on focused ultrasound to push microbubbles, along with drug molecules, across the barrier without causing much harm. Microbubbles are a contrast agent of ultrasound, and they are extremely sensitive to waves of ultrasound. Microbubbles puff up and back down as ultrasound waves pass through them, creating a localized pumping action. This motion can generate a push in the same direction as the ultrasound waves are heading, which allows it to be used to target the drug to enter the brain in a specific area.
By combining cavitation dose painting with passive cavitation imaging, a technique that can visualize the concentration of microbubbles, the researchers were able to see how much drug ends up actually being transported across the blood brain barrier. To confirm their findings, the team compared the results against positron emission tomography (PET) imaging and showed a “pixel by pixel” correlation between PET and ultrasound imaging in terms of tracking drug particles.
Open access study in Scientific Reports: Cavitation dose painting for focused ultrasound-induced blood-brain barrier disruption…