A team of researchers from Washington University, National Institutes of Health and University of Illinois have developed a wireless device the width of a human hair that can be implanted in the brain and activated by remote control to deliver drugs. The team state that the technology, demonstrated for the first time in mice, may one day be used to treat pain, depression, epilepsy and other neurological disorders in people by targeting therapies to specific brain circuits. They predict that this approach potentially could deliver therapies that are much more targeted but have fewer side effects. The study is published in the journal Cell.
The research is a major step forward in pharmacology and builds on earlier work in optogenetics, a technology that makes individual brain cells sensitive to light and then activates those targeted populations of cells with flashes of light. Because it’s not yet practical to re-engineer human neurons, the researchers made the tiny wireless devices capable of delivering drugs directly into the brain, with the remote push of a button. The team state that in the future, it should be possible to manufacture therapeutic drugs that could be activated with light. They go on to add that with one of these tiny devices implanted, they could theoretically deliver a drug to a specific brain region and activate that drug with light as needed.
Previous studies have attempted to deliver drugs or other agents, such as enzymes or other compounds, to experimental animals and have required the animals to be tethered to pumps and tubes that restricted their movement. However, the new devices in the current study were built with four chambers to carry drugs directly into the brain. By activating brain cells with drugs and with light, the researchers state that they are getting an unprecedented look at the inner workings of the brain.
The team explain that this is the kind of revolutionary tool development that neuroscientists need to map out brain circuit activity and the current study is very much in line with the goals of the NIH’s BRAIN Initiative. They go on to explain that the NIH BRAIN (Brain Research through Advancing Innovative Technologies) Initiative is a program designed to accelerate the development and application of new technologies to shed light on the complex links between brain function and behaviour. The results show literally that the medical community can deliver drug therapy with the press of a button.
The device embeds microfluid channels and microscale pumps, however, it is soft like brain tissue and can remain in the brain and function for a long time without causing inflammation or neural damage. As part of the current 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. However, the researchers were able to interfere with that light-activated pursuit by remotely controlling the release of a drug that blocks the action of dopamine on its receptors.
The researchers also believe that similar, more flexible devices could have applications in areas of the body other than the brain, including peripheral organs. They go on to note that they’ve successfully produced and demonstrated an implantable, cellular-scale microfluidic and micro-optical interface to biology, with application opportunities not only in the brain but in other parts of the nervous system and other organs as well.
The team surmise that for now, the devices contain only four chambers for drugs and in the future they plan to incorporate a design much like a printer’s ink cartridge so that drugs can continue to be delivered to specific cells in the brain, or elsewhere in the body, for as long as required without the need to replace the entire device.