One of the biggest issues in pharmacology involves unwanted side effects and their effect on the body. Drugs designed to treat one ailment could cause another condition, creating a dangerous and inconvenient spiral of health problems. The more targeted a drug is — that is, the more successfully it can affect only that which it is meant to — the less likely it will cause unwanted side effects. Inserting a drug for the brain directly into the brain is a good way to target. The ability to target specific circuits within the brain is even better.

A team of researchers has developed a device, as thin as a single human hair, which can be implanted in the brain and deliver drugs by the command of a remote control.

Demonstrated recently for the first time on mice, this technology is a major step forward in pharmacology, and may be used one day to treat depression, pain, epilepsy, and other neurological brain disorders by targeting therapies to specific brain circuits.

The study was conducted by researchers at Washington University School of Medicine in St. Louis and the University of Illinois at Urbana-Champaign, and builds on earlier work concerning optogenetics — a method combining optics and genetics. The technology makes individual cells in the brain sensitive to light, then activates those specific cells with flashes of light. It isn’t practical to re-engineer human neurons yet, so researchers came up with the device instead.

"In the future, it should be possible to manufacture therapeutic drugs that could be activated with light," said co-principal investigator Dr. Michael R. Bruchas, associate professor of anesthesiology and neurobiology at Washington University, in a press release. "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."

There have been attempts in the past to deliver drugs to experimental animals, but they always required the animal to be tethered to a pump or tube that restricted their movement. The new device does no such thing and is offering researchers an unprecedented look at the inner workings of the brain.

"This is the kind of revolutionary tool development that neuroscientists need to map out brain circuit activity," said Dr. James Gnadt, program director at the National Institute of Neurological Disorders and Stroke at the National Institutes of Health (NIH) in a press release. "It's very much in line with the goals of the NIH's BRAIN Initiative."

The NIH BRAIN (Brain Research through Advancing Innovative Technologies) Initiative is a program that hopes to fast-track the development and application of new tools to shed light on the complex links between brain function and behavior.

The new device has the ability to stimulate neurons and influence behavior, but is physically soft — able to remain in the brain tissue for a long time without causing damage or inflammation.

"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 behavior with light or with a particular drug, we can simply point the remote at the animal and press a button."

For now, the device only has a limited capacity to carry drugs, but researchers hope that in the future they can create a design that allows drugs to be administered for as long as needed without replacement.

Source: Jeong JW , McCall JG, et al. Wireless optofluidic systems for programmable in vivo pharmacology and optogenetics. Cell. 2015.