- Development of next-generation neural interface technology, integrating electrophysiology and deep brain imaging

- This research was published in Advanced Functional Materials, an internationally renowned journal.

The University of Seoul announced that a research team led by Professor Dong-Wook Park from the School of Electrical and Computer Engineering, in collaboration with the University of Wisconsin-Madison and Inscopix, has developed BioCLEAR, a transparent neural electrode system that can simultaneously measure electrical and optical signals from deep-brain neurons. 

The research findings were published in the paper titled "Transparent Inorganic–Organic Bilayer Neural Electrode Array and Integration to Miniscope System for In Vivo Calcium Imaging and Electrophysiology" on October 23 in Advanced Functional Materials, an internationally renowned journal (IF 19, top 4.5% in JCR).

BioCLEAR is recognized as a multimodal neural measurement technology that can perform both electrophysiology and calcium imaging on a single platform.

BioCLEAR uses a hybrid organic-inorganic structure that combines a silver nanowire (AgNW)–based inorganic conductor with a doped PEDOT:PSS organic polymer layer. This structure addresses the opacity and imaging interference issues of conventional metal electrodes while providing high electrical performance and flexibility. The performance of the transparent neural electrode was systematically validated using several methods, including electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), accelerated lifetime testing, cell viability assessments, and rodent animal experiments.

▶ BioCLEAR Electrodes Fabricated on a Silicon Wafer and an Overview of the System

The integration of the transparent neural electrode array with the GRIN lens system from Inscopix, a Silicon Valley-based neuroimaging company, enabled simultaneous detection of both electrical signals and calcium-based optical signals from neurons. Researchers validated this integrated system using in vivo animal models. Because of BioCLEAR's high transparency, electrical and optical signals can be observed at the same time with minimal image distortion.

▶ BioCLEAR Deep Brain Implantation, Calcium Imaging, and Electrophysiology Data

This provides a foundation for researchers to analyze the interactions between neuronal electrical excitation and calcium dynamics with precision. BioCLEAR's high transparency will make it suitable for integration with optogenetics and two-photon imaging technologies. The research team expects that this technology has significant potential for expansion into advanced neuroscience applications, including brain-computer interfaces (BCI), neuroprosthetics, and devices for monitoring and treating brain disorders.

Professor Dong-Wook Park stated, "BioCLEAR is a new tool enabling simultaneous electrical and optical observation of neuronal activity in deep brain regions," and added that "this technology will enhance the technical competitiveness of BCI and neural electrode technologies, and contribute to the development of the brain engineering ecosystem."

▶ Dr. Dongjun Han, University of Seoul; Dr. Jonathan Nassi, Inscopix; Professor Justin Williams, University of Wisconsin-Madison; Professor Dong-Wook Park, University of Seoul 

This study is considered a representative example of successful international collaborative research. Dr. Dongjun Han, a postdoctoral researcher (first author) at the University of Seoul’s School of Electrical and Computer Engineering, led the analysis of BioCLEAR's materials, structure, electrochemical characteristics, and optical properties. The in vivo validations, including deep-brain experimental validation, were completed in collaboration with the University of Wisconsin-Madison and Inscopix in the United States.

This research was supported by the Ministry of Science and ICT and the National Research Foundation of Korea (NRF) through the Global Basic Research Laboratory Program, the Mid-Career Researcher Program, and the National Agenda Research Project. It was also supported by the National Institutes of Health/NIMH grant 1R44MH122084 to Inscopix, Inc.  This research was conducted based on the research infrastructure of the Center for Semiconductor Research (UOS Fab) at the University of Seoul.