Ultrasound tech shows promise for targeted drug delivery in the brain

Researchers at ETH Zurich, the University of Zurich, and the University Hospital Zurich have made a groundbreaking discovery in the field of medical technology. They have successfully guided microvehicles, tiny gas bubbles, through the intricate blood vessels of a living animal’s brain using ultrasound waves. This breakthrough holds great promise for the future of targeted drug delivery, potentially revolutionizing the treatment of brain tumors, hemorrhages, and neurological and psychological conditions.

Traditional medication often struggles to effectively treat these conditions due to the challenges posed by the blood-brain barrier. Additionally, medications that do reach the brain tend to have widespread side effects. To address these limitations, scientists have been working on developing mini-transporters capable of navigating the complex network of blood vessels within the brain.

Unlike alternative navigation technologies that rely on magnetic fields, ultrasound offers several advantages. It is widely used in the medical field and can safely penetrate deep into the body. The researchers utilized gas-filled microbubbles, coated in lipids similar to biological cell membranes, for their microvehicles. These bubbles, measuring a mere 1.5 micrometers in diameter, are already approved for use in humans as contrast material in ultrasound imaging.

The remarkable finding of the study is that these microbubbles can be precisely guided through the brain’s blood vessels using ultrasound waves. This means that the microvehicles can potentially be loaded with medications and delivered to specific areas of the brain, increasing drug efficacy while minimizing side effects.

One notable advantage of ultrasound-guided microbubbles is their biodegradability. Once they have completed their task, they naturally dissolve within the body. In contrast, magnetic-based microvehicles require non-biodegradable materials and pose challenges for safe disposal.

The smooth and small nature of the microbubbles allows researchers to navigate them effortlessly through narrow capillaries, leading to improved precision in drug delivery. To achieve this, the team employed a sophisticated method involving small transducers attached to the animal’s skull. These transducers generate ultrasonic vibrations that propagate through the brain as waves. By adjusting the output of each transducer, the researchers can control the movement of the microbubbles against the natural blood flow, directing them towards the targeted areas.

Real-time imaging using two-photon microscopy helps the researchers monitor and adjust the microvehicles’ movements. Looking ahead, the team aims to use ultrasound technology itself for imaging, further enhancing its potential in medical applications.