We’ve learned a lot about how the brain works, functions, and illnesses since being able to detect electrical activity in the brain. However, being able to acquire signals directly from inside the brain (through neural interfacing devices) during daily life activities could take neuroscience and neuromedicine to completely new levels. So far, most of this activity has been measured using electrodes placed on the scalp (through EEG). Although this concept had high hopes, the implementation of brain interfaces has proved to be very difficult. In order to survive an environment as severe as the human body, the materials utilized in the tiny electrodes that make contact with the neurons must be flexible while still being robust. In the past, efforts to create long-lasting brain interfaces have met with failure because the electrodes’ electrical effectiveness degrades over time due to the body’s normal biological reactions, such as inflammation. However, what if there was a feasible method to deliver anti-inflammatory medications close to the brain’s electrodes?
Scientists from Korea have created and published a new multifunctional brain interface that can simultaneously record neural activity and administer liquid medicines to the implant site in Microsystems & Nanotechnology. They utilize a flexible 3D structure instead of rigid devices to collect numerous neural impulses from a large region using an array of microneedles, and then transmit those signals to an external circuit using thin metallic conductive lines. One of the most impressive features of this research is that the scientists were able to integrate microfluidic channels on a plane parallel to the conductive lines by carefully stacking and micromachining several polymer layers. When the tiny reservoir (which holds the medicines) is filled, a constant stream of liquid is sent to the microneedles through these channels.
Brain interface studies on live rats were used to verify the technique, which was then followed by a drug concentration measurement in the tissue around the needles. DGIST professor Sohee Kim, who led the study, says, “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.” Prof. Kim’s findings are very encouraging in this regard. The creation of long-lasting multifunctional brain interfaces will have ramifications for a wide range of fields. KIMM’s Dr. Yoo Na Kang, the study’s lead author, says, “Our technology may be ideal for brain-machine interfaces, which allow paralyzed individuals to operate robotic limbs or legs with their thoughts, and for curing neurological disorders over years by utilizing electrical and/or chemical stimulation. Hopefully, a direct and long-lasting link to the brain will be beneficial to a large number of individuals!
Journal Reference: Yoo Na Kang, Namsun Chou, Jae-Won Jang, Han Kyoung Choe, Sohee Kim. A 3D flexible neural interface based on a microfluidic interconnection cable capable of chemical delivery. Microsystems & Nanoengineering, 2021; 7 (1) DOI: 10.1038/s41378-021-00295-6