A small wireless implant could help kill deadly brain tumors

"The nanoparticles help us target the treatment to only the tumor, so the side effects will be relatively less compared with chemotherapy and radiation," said Hamed Arami, Ph.D., co-lead author of the paper.

Photothermal treatments, which use light to heat up nanoparticles while fighting brain tumors, are nothing new; however, they can only be applied during surgeries while the tumor is exposed to the light source.

The late Sam Gambhir, MD, former chair of radiology at Stanford Medicine and a pioneer in molecular imaging contacted Ada Poon, Ph.D., a Stanford University associate professor of electrical engineering to come up with a new fashion that'll help fight brain tumors without baring the brain.

"When I got that email from Sam, I saw that what he wanted to do was really aligned with what our lab is focusing on, which is using electronics to treat diseases," Poon said.

How does it work?

After a four-year hard work, researchers developed a system that can generate heat precisely at the site of tumors to defeat them. The wireless implant is implanted between the skin and the skull; then the gold nanoparticles are injected into the tumor through a tiny hole in the skull. The implant emits infrared light, which penetrates brain tissue to activate the nanoparticles that increase in temperature by up to 5 degrees Celsius. Various sizes of tumors can be killed by adjusting the power and wavelength of light.

"We think this short amount of heating, which is in the clinically acceptable range, is not affecting normal activities," Arami said.

According to the researchers, mice that received the treatment lived longer than untreated mice. The survival times doubled, even tripled on average. Combined with chemotherapy, the treatment was a success in making the mice even longer.

"Glioblastoma patients don't often live more than two to three years after diagnosis because you can't get rid of every part of the tumor, and the tumor can become drug-resistant or radiation-resistant," Arami said. "The goal is to combine this with other treatments to extend survival."

Abstract:

Current clinical brain tumour therapy practices are based on tumour resection and post-operative chemotherapy or X-ray radiation. Resection requires technically challenging open-skull surgeries that can lead to major neurological deficits and, in some cases, death. Treatments with X-ray and chemotherapy, on the other hand, cause major side-effects such as damage to surrounding normal brain tissues and other organs. Here we report the development of an integrated nanomedicine–bioelectronics brain–machine interface that enables continuous and on-demand treatment of brain tumours, without open-skull surgery and toxicological side-effects on other organs. Near-infrared surface plasmon characteristics of our gold nanostars enabled the precise treatment of deep brain tumours in freely behaving mice. Moreover, the nanostars’ surface coating enabled their selective diffusion in tumour tissues after intratumoral administration, leading to the exclusive heating of tumours for treatment. This versatile remotely controlled and wireless method allows the adjustment of nanoparticles’ photothermal strength, as well as power and wavelength of the therapeutic light, to target tumours in different anatomical locations within the brain.