Researchers have developed a new wireless device the width of a human hair that can be implanted in the brain and activated by remote control to deliver drugs.
The technology, demonstrated for the first time in mice, one day may be used to treat pain, depression, epilepsy and other neurological disorders in people by targeting therapies to specific brain circuits, according to the researchers at Washington University School of Medicine in St Louis and the University of Illinois at Urbana-Champaign.
"In the future, it should be possible to manufacture therapeutic drugs that could be activated with light," said co-principal investigator Michael R Bruchas, associate professor of anesthesiology and neurobiology at Washington University.
"With one of these tiny devices implanted, we could theoretically deliver a drug to a specific brain region and activate that drug with light as needed. This approach potentially could deliver therapies that are much more targeted but have fewer side effects," Bruchas said.
Previous attempts to deliver drugs or other agents, such as enzymes or other compounds, to experimental animals have required the animals to be tethered to pumps and tubes that restricted their movement.
But the new devices were built with four chambers to carry drugs directly into the brain. By activating brain cells with drugs and with light, the scientists are getting an unprecedented look at the inner workings of the brain.
The new devices ultimately may help people with neurological disorders and other problems, according to co-first authors Jae-Woong Jeong, a former postdoctoral researcher at the University of Illinois and now assistant professor of electrical, computer and energy engineering at the University of Colorado, Boulder, and Jordan G McCall, a graduate student in the Bruchas lab.
"Now, we literally can deliver drug therapy with the press of a button," McCall said.
"We've designed it to exploit infrared technology, similar to that used in a TV remote. If we want to influence an animal's behaviour with light or with a particular drug, we can simply point the remote at the animal and press a button," he said.
"The device embeds microfluid channels and microscale pumps, but it is soft like brain tissue and can remain in the brain and function for a long time without causing inflammation or neural damage," Jeong added.
As part of the study, the researchers showed that by delivering a drug to one side of an animal's brain, they could stimulate neurons involved in movement, which caused the mouse to move in a circle.
In other mice, shining a light directly onto brain cells expressing a light-sensitive protein prompted the release of dopamine, a neurotransmitter that rewarded the mice by making them feel good. The mice then returned to the same location in a maze to seek another reward.
The study will be published in the journal Cell.