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Glioblastoma is a virtual death sentence. Doctors treat this aggressive form of brain cancer with a combination of surgery, chemotherapy, and radiation – but no existing treatment is particularly effective. Some estimates indicate that, on average, people diagnosed with glioblastoma survive fewer than 15 months. 

Dr. Xian Wang is using a technology called acoustic microbubble microrobots to attack and destroy cancer cells. And he hopes that, one day, this deadly disease will be more treatable. 

“We are taking a physical approach to treating glioblastoma,” says Dr. Wang, an assistant professor of mechanical and materials engineering at the Ingenuity Lab Research Institute. “We want to destroy a tumour’s cellular structure by basically tearing it apart.”

To do that, Dr. Wang uses tiny air-filled bubbles that are more commonly used as a contrast agent in ultrasound scans. These microbubbles help improve the visibility of blood flow in medical imaging, but their movement inside the human body can be guided with magnetism. And their behaviour can be manipulated with high-intensity focused ultrasound (HIFU), a higher energy form of the same ultrasound technology used in medical imaging.

Dr. Wang is developing ways to use magnetism to lead microbubbles to the site of a glioblastoma brain tumour. Then, he uses the acoustic field generated by HIFU to get the microbubbles to break a tumour apart cell by cell – with minimal damage to the surrounding tissue. His research is funded through a $100,000 grant from Brain Canada’s Future Leaders in Canadian Brain Research program. He is also working with collaborators at SickKids hospital in Toronto and Kingston General Hospital, and is expanding collaboration with Dr. Andrew Craig at the Sinclair Cancer Research Institute – partnerships that will add biomedical and clinical expertise to the research in his lab.

Dr. Wang uses microbubbles that have a lipid structure. They are made of fat, which allows them to move through the human body. But they also contain iron, which is how magnets can guide their movements. And once the microbubbles reach the site of a tumour, they can be stimulated with HIFU to vibrate, burst, or shrink and expand repeatedly. Dr. Wang is exploring which of the three actions is best suited to destroying cancer cells. 

He is also looking at whether microbubbles could be used to deliver pharmaceutical treatments directly to a tumour. HIFU can temporarily open the blood-brain barrier, a protective membrane that separates blood flow from brain tissue and restricts passage between the two. The blood-brain barrier blocks most drugs from the brain. But certain types of drugs can be attached to microbubbles, and if HIFU can open the blood-brain barrier, then those microbubbles might be guided through it. This would open new treatment possibilities by making it possible to target glioblastoma treatments much more precisely. 

 Visibility is a significant challenge in Dr. Wang’s work. Microbubbles are tiny – just 10 micrometres across. And even with advanced imaging technology, it’s difficult to see exactly how they are moving inside the brain. But controlling their movement and behaviour opens entirely new avenues for treating brain conditions. And the potential applications aren’t limited to glioblastoma. The ability to navigate the brain and deliver treatment could help treat conditions like Parkinson’s, Alzheimer’s, and epilepsy, too. 

“It is extremely challenging to treat the brain, and this is a perfect scenario for us to apply the technology,” Dr. Wang says. “Glioblastoma poses a significant challenge to Canadians’ health, and this environment is very hard to reach. But it is reachable with the right technology.”