Transparent Inorganic-Organic Bilayer Neural Electrode Array and Integration to Miniscope System for In Vivo Calcium Imaging and Electrophysiology

Abstract

Transparent neural electrodes serve not only to detect neural signals and stimulate nerve tissue but also to significantly reduce image artifacts in various medical imaging modalities. Furthermore, when integrated with an optical system, they offer the detection of both electrical and optical signals at the targeted location. In this study, a cost-effective, highly transparent, and conductive inorganic-organic neural electrode array (BioCLEAR) comprising a random network of AgNW and GOPS-doped PEDOT:PSS is proposed. Additionally, a system capable of conducting in vivo electrophysiology and calcium imaging in specific brain regions by integrating BioCLEAR with an implantable GRIN lens is introduced. By harnessing the advantages of both materials, this electrode demonstrates high conductivity, excellent biocompatibility, and optical transmittance exceeding 85% at a wavelength of 550 nm. The viability of BioCLEAR is demonstrated through various in vitro and in vivo analyses, including electrochemical EIS, CV, accelerated soak tests, cell viability assessments, neural electrophysiological recording, and calcium imaging in rodents. By integrating BioCLEAR with a GRIN prism lens, in vivo electrophysiology and calcium imaging are successfully conducted with minimal occurrence of image artifacts. The BioCLEAR system holds significant promise for concurrently measuring and analyzing electrical signals and imaging data from the nervous system.