Though we’ve made incredible strides in the treatment and prevention of brain cancer, more than 24,000 Americans are still affected by brain cancer every year— resulting in more than 18,000 deaths in just 2023 alone, according to the American Cancer Society.
Treatment options usually involve some sort of combination of surgery and chemotherapy. However, brain cancers are notably resistant to chemotherapy thanks to what’s called the blood-brain barrier: a protective lining of blood vessels around the brain to protect it from harmful large molecules. Unfortunately, it’s a double-edged sword that also makes it difficult for chemotherapy drugs to actually target tumor cells that are hiding behind the barrier.
One way to get past the barrier is via ultrasound, which moves the blood vessels just enough to allow drug compounds through. This is also quite difficult to accomplish, since the skull is an even bigger barrier that stops ultrasound in the first place. Doctors get around this by placing ultrasound devices around the skull and focusing ultrasound waves using an MRI immediately after chemotherapy has been given.
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It’s a costly, time-intensive process that isn’t guaranteed to work. And it’s usually only done one time, even though brain cancers often need multiple bouts of chemotherapy to eradicate.
Enter Thanh Nguyen and other biomedical engineers at the University of Connecticut. In a new study published in Science Advances this week, Nguyen and his team outline the development of a new type of ultrasound device that is biodegradable. It can be implanted inside the brain and used to help drugs make their way past the blood-brain barrier—after which it safely dissolves without problem.
“We can repeatedly use it, allowing chemo to penetrate the brain and kill off tumor cells,” Nguyen said in a press release.
The new device builds upon previous designs for an implantable ultrasound that’s made of ceramic. Nguyen’s lab instead chose to make their device using a specially-designed version of crystallized glycine (a common protein building block in the body) that is able to break down in six weeks.
The new ultrasound device was tested in mice with brain cancer, who were treated with a chemotherapy drug called paclitaxel, or PTX. The glycine ultrasound successfully allowed PTX to bypass the blood-brain barrier and cause the brain tumor to shrink and let them live twice as long as they would have otherwise. The device, even after it had degraded, did not have any adverse effects on the health of the mice.
The new tests are just a proof of concept, and the lab is now gearing up to run more ambitious tests on larger animals. Should those trials be successful, however, it’s not difficult to see the device being one day used in humans afflicted with brain cancer, and enable more repeated chemotherapy treatments that are less invasive and costly. For the tens of thousands who will be diagnosed with brain cancer later in life, this could provide a huge lifeline down the road.
