Being able to measure the electrical activity of the brain has helped us gain a much better understanding of the brain’s processes, functions, and diseases over the past decades. So far, much of this activity has been measured via electrodes placed on the scalp (through electroencephalography (EEG)); however, being able to acquire signals directly from inside the brain itself (through neural interfacing devices) during daily life activities could take neuroscience and neuromedicine to completely new levels. A major setback to this plan is that, unfortunately, implementing neural interfaces has proven to be remarkably challenging.
The materials used in the minuscule electrodes that make contact with the neurons, as well as those of all connectors, should be flexible yet durable enough to withstand a relatively harsh environment in the body. Previous attempts at developing long-lasting brain interfaces have proven challenging because the natural biological responses of the body, such as inflammation, degrade the electrical performance of the electrodes over time. But what if we had some practical way to locally administer anti-inflammatory drugs where the electrodes make contact with the brain?
In a recent study published in Microsystems & Nanoengineering , a team of Korean researchers developed a novel multifunctional brain interface that can simultaneously register neuronal activity and deliver liquid drugs to the implantation site. Unlike existing rigid devices, their design has a flexible 3D structure in which an array of microneedles is used to gather multiple neural signals over an area, and thin metallic conductive lines carry these signals to an external circuit. One of the most remarkable aspects of this study is that, by strategically stacking and micromachining multiple polymer layers, the scientists managed to incorporate microfluidic channels on a plane parallel to the conductive lines. These channels are connected to a small reservoir (which contains the drugs to be administered) and can carry a steady flow of liquid toward the microneedles.
The team validated their approach through brain interface experiments on live rats, followed by an analysis of the drug concentration in the tissue around the needles. The overall results are very promising, as Prof. Sohee Kim from Daegu Gyeongbuk Institute of Science and Technology (DGIST), Korea, who led the study, remarks: “ The flexibility and functionalities of our device will help make it more compatible with biological tissues and decrease adverse effects, all of which contribute to increasing the lifespan of the neural interface .”
The development of durable multifunctional brain interfaces has implications across multiple disciplines. “ Our device may be suitable for brain–machine interfaces, which enable paralyzed people to move robotic arms or legs using their thoughts, and for treating neurological diseases using electrical and/or chemical stimulation over years ,” explains Dr. Yoo Na Kang of the Korea Institute of Machinery & Materials (KIMM), first author of the study. Let us hope many people benefit from a direct and durable connection to the brain!
Reference
Authors:
Yoo Na Kang 1 , Namsun Chou 2 , Jae-Won Jang 3 , Han Kyoung Choe 4 , and Sohee Kim 3 *
Title of original paper:
A 3D flexible neural interface based on a microfluidic interconnection cable capable of chemical delivery
Journal:
Microsystems & Nanoengineering
DOI:
10.1038/s41378-021-00295-6
Affiliations:
1 Department of Medical Assistant Robot, Korea Institute of Machinery & Materials (KIMM)
2 Center for BioMicrosystems, Korea Institute of Science and Technology (KIST)
3 Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science
and Technology (DGIST)
4 Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST)
*Corresponding author’s email: soheekim@dgist.ac.kr
About Daegu Gyeongbuk Institute of Science and Technology (DGIST)
Daegu Gyeongbuk Institute of Science and Technology (DGIST) is a well-known and respected research institute located in Daegu, Republic of Korea. Established in 2004 by the Korean Government, the main aim of DGIST is to promote national science and technology, as well as to boost the local economy.
With a vision of “Changing the world through convergence", DGIST has undertaken a wide range of research in various fields of science and technology. DGIST has embraced a multidisciplinary approach to research and undertaken intensive studies in some of today's most vital fields. DGIST also has state-of-the-art-infrastructure to enable cutting-edge research in materials science, robotics, cognitive sciences, and communication engineering.
Website: https://www.dgist.ac.kr/en/html/sub01/010204.html
About the authors
Prof. Sohee Kim, currently with DGIST, is developing various soft bioelectronic devices based on flexible materials to interface our central and peripheral nervous system with assistive or rehabilitative systems, such as robotic hands.
Dr. Yoo Na Kang was the first student that Dr. Sohee Kim supervised after she moved to DGIST. Kang is now working at Korea Institute of Machinery and Materials alongside a team seeking to develop medical assistive robots.
Experimental study
Animals
18-Aug-2021