Hair-thin electrode extends brain signal recording duration threefold
– Nano-coating technology triples electrode lifespan, enabling long-term brain signal monitoring
image: To apply a uniform, thin polymer coating to the flexible neural electrode surface, a photoinitiated chemical vapor deposition (piCVD) process was employed. In this low-pressure vapor deposition process, monomers and crosslinkers (HEMA and EGDMA) are introduced into a vacuum chamber in the vapor phase. These precursors are activated by UV irradiation and polymerize directly on the electrode surface. The resulting polymer coating swells upon exposure to moisture, preventing proteins and cells from adhering to the electrode surface.
Credit: Korea Institute of Science and Technology
The rapid progression of an aging society has led to a sharp rise in patients with neurodegenerative diseases such as dementia and Parkinson’s disease, making it a critical issue in healthcare and welfare. To properly understand and treat such conditions, it is essential to continuously monitor the electrical signals exchanged by neurons deep inside the brain. However, conventional electrodes lose functionality within one month due to inflammation and scar tissue formation after implantation, limiting their use in long-term research and therapy.
A research team led by Dr. Hyejeong Seong at the Brain Convergence Research Division of the Korea Institute of Science and Technology (KIST, President Sang-Rok Oh), in collaboration with Prof. Seongjun Park at Seoul National University (President Hong-Lim Ryu), announced the development of a breakthrough coating technology that extends the lifespan of implanted electrodes from 1 month to over 3 months. This achievement establishes a foundation for stable, long-term recording of brain signals, greatly broadening opportunities for both neuroscience research and clinical applications.
The team fabricated the electrode using flexible plastic instead of rigid silicon to minimize tissue damage, and applied a special nano-coating only 100 nanometers (nm, one-billionth of a meter) thick to enhance durability. With a thickness about one-third that of a human hair, the electrode can not only record neuronal activity in real time but also deliver drugs when needed. Critically, the coating expands like a sponge upon contact with cerebrospinal fluid, preventing proteins and immune cells from adhering to the electrode surface. This suppresses inflammation and scar tissue formation, ensuring long-term, stable contact between the electrode and neurons.
The electrode’s performance was validated in animal studies. In mice, the coated electrodes reduced inflammatory responses by more than 60% and improved neuronal survival by 85% compared to conventional electrodes. Moreover, the signal-to-noise ratio (SNR) consistently improved over time, demonstrating stable and reliable long-term brain signal recordings. These results highlight the practical utility of the technology for both brain disease research and neural signal–based technologies.
The new technology provides a platform for long-term studies of degenerative brain diseases such as dementia and Parkinson’s disease, while also contributing to the commercialization of brain-computer interface (BCI) systems. Furthermore, it is expected to enhance the stability and performance of various implantable medical devices, including heart stents and artificial joints, creating wide-ranging beneficial effects across the medical device industry. Moving forward, the team plans to evaluate the electrode’s applicability in rehabilitation monitoring, mental health management, and brain disease diagnostics, and to expand the coating technology to other implantable medical devices to maximize its industrial value.
Dr. Seong at KIST stated, “This research is highly meaningful as it fundamentally solves the electrode lifespan problem, enabling long-term and stable acquisition of neural signals.”
Prof. Park at Seoul National University commented, “This novel electrode technology will not only advance brain research but also provide a crucial foundation for developing new treatment methods for neurological disorders.”
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KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://www.kist.re.kr/eng/index.do
This research was supported by the Ministry of Science and ICT (Minister Kyung-hoon Bae) through KIST’s Major Program, the Excellent Young Researcher Program, the Mid-Career Researcher Program , and the Boston-Korea Project. The results were published in the international journal Biomaterials (Impact Factor 12.9, JCR Top 3.6%).