Ultrasound and microbubbles offer targeted drug delivery to the brain

A novel, noninvasive approach to targeted drug delivery to the brain using ultrasound has been presented by researchers from the University of Oxford, who performed the work in collaboration with the University of Twente in the Netherlands, at the Acoustics ’17 Boston meeting.

The blood–brain barrier protects the human brain and has been challenging for drug companies to overcome in the targeted delivery of therapy for diseases such as brain cancer and Alzheimer’s. Using ultrasound and tiny bubbles, the researchers from Oxford and Twente have developed a noninvasive way of opening the blood–brain barrier.

“The key advantage of our system is that it uses three modalities — involving light, sound and electrical fields — to simultaneously monitor acoustic emissions, blood–brain barrier disruption and recovery, and the biological response of blood–brain barrier cells in real-time,” explained Miles M. Aron from the University of Oxford in a press release.

The investigators use ultrasound and microbubbles to disrupt the blood–brain barrier and then ‘listened’ to the acoustic emissions of the microbubbles for treatment control. Microbubbles that interact with an ultrasound field are known as cavitation agents, of which there are several approved by the US Food and Drug Administration (FDA) already for the enhancement of contrast in ultrasound imaging.

“The treatment can be monitored externally by ‘listening to the re-radiated sound from the cavitation agents interacting with the ultrasound field,” Aron continued. “These acoustic emissions provide information regarding the energy of cavitation within the blood vessels and are already being used to adjust ultrasound parameters in real-time to reduce the likelihood of damaging healthy cells during treatment.”

The session, featured at the Acoustics ’17 Boston meeting, was titled ‘Ultrasound-mediated blood–barrier disruption: Correlation with acoustic emissions’ and was presented by Aron.