Ultrasound-mediated drug delivery to the brain: principles, progress and prospects

The blood-brain barrier (BBB) limits drug delivery to the central nervous system. When combined with microbubbles, ultrasound can transiently permeate blood vessels in the brain. This approach, which can be referred to as sonoporation or sonopermeabilization, holds significant promise for shuttling large therapeutic molecules, such as antibodies, growth factors and nanomedicine formulations, across the BBB. We here describe the basic principles of BBB permeation using ultrasound and microbubbles, and we summarize several (pre-) clinical studies showing the potential of BBB opening for improving the treatment of cancer and neurodegenerative disorders.