Researchers at the Washington University of Medicine, St. Louis, and University of Illinois, Urbana-Champaign have created a futuristic remote-controlled tissue implant which with the help of which neuroscientists can shine lights and inject drugs into neurons inside brain cells. The details of the ultra-thin and minimally invasive device were published in the journal Cell. The research was partially funded by the National Institutes of Health (NIH).
Brain Controlled Device — Why Design Such A Device
The Bruchas lab examine circuits involved in various signaling disorders, such as stress, addiction, depression and pain. Scientists studying these circuits often have to choose between injecting drugs via bulky metal tubes and delivering lights via fiber optics. Both these procedures are highly invasive, with risks of damaging parts of the brain or introducing some experimental condition that may affect natural movements.
Addressing these difficulties, Jae-Woong Jeong, Ph.D., a former bioengineer at the University of Illinois at Urbana-Champaign, worked in collaboration with Jordan G. McCall, Ph.D., a graduate student in the Bruchas lab to develop a remote-controlled opt fluidic implant. The latter is constructed using soft materials, with a diameter one-tenth that of a human hair.
“We used powerful nano-manufacturing strategies to fabricate an implant that lets us penetrate deep inside the brain with minimal damage”, stated senior author John A. Rogers Ph.D., Professor of Materials Science, University of Illinois at Urbana-Champaign. “Such ultra-miniaturized devices have tremendous potential for science and medicine”.
Researchers worked on 30 different prototypes before settling on a functioning design. The implant was fabricated using techniques used to manufacture semi-conductor computer chips. The device can accommodate up to four drugs, and also contains four microscale inorganic light-emitting diodes (LED’s). Researcher also added an electric heater beneath the expandable material at the bottom of the drug holding reservoirs. This is meant to control drug delivery – bottom expands when temperature rises and pushes the drug into the brain.
The opt fluidic implant is 80 micrometers thick and 500 micrometers wide, making it thinner than the metallic tubes (cannulas) that scientists conventionally use to inject drugs into the brain. Moreover, compared to a typical cannula, the implant rendered much less damage to brain tissue.
Testing The Device
To proper its effectiveness and superior drug delivery mechanism, scientists surgically inserted the implant into the brains of mice. In certain experiments, they demonstrated that the implant could be used to precisely map neural circuits by injecting viruses that tag cells with genetic dyes. Furthermore, using the implant, scientists injected a drug similar to morphine into the ventral tegmental area (VTA) of the brain and made the mice walk in circles.
The implant’s combined light and drug delivery was also tested by researchers. commanding the device to shine laser impulses on brain cells, mice with light-sensitive VTA neurons were made to stay on one side of their cage. This activity was lost when scientists commanded the device to simultaneously inject a drug that inhibited this neural communication. What’s notable is that in all the experiments, the mice were at a distance of least three feet from the signalling antenna.
Conclusions And Prospects
In the published study, scientists have provided detailed instructions to replicate the implant. “It unplugs a world of possibilities for scientists to learn how brain circuits work in a more natural setting”, commented senior author Michael R. Bruchas, Ph.D., Associate Professor of Anaesthesiology and Neurobiology at Washington University School of Medicine.
“This is the kind of revolutionary tool development neuroscientists need to map out brain circuit activity”, stated James Gnadt, Ph.D., Program Director at the National Institute of Neurological Disorders and Stroke.
Dr. Jeong, now Assistant Professor of Electrical, Computer, and Energy Engineering at University of Colorado Boulder said that the interdisciplinary research study aimed to create a device that met the most prominent needs of today’s neuroscientists. Dr. Bruchas concluded that an open and collaborator approach to neuroscience was the only way to guarantee a proper understanding of healthy brain circuits – the development and use of this implant could provide just that.