Flexible Multichannel Neural Probe Developed by Electropolymerization for Localized Stimulation and Sensing. Issue 8 (1st April 2022)

• Record Type: Journal Article
• Authors: Chik, Gary Kwok Ki; Xiao, Na; Ji, Xudong; Tsang, Anderson Chun On; Leung, Gilberto Ka Kit; Zhang, Shiming; Tin, Chung; Chan, Paddy Kwok Leung
• Is Part Of: Advanced materials technologies. Volume 7:Issue 8(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-01
• Subjects: bioelectronics -- electropolymerization -- hydrogel -- neural probe -- neuronal stimulation; Materials science -- Periodicals; Technological innovations -- Periodicals; Materials science; Technological innovations; Periodicals; 620.1105
• DOI: 10.1002/admt.202200143
• Languages: English
• ISSNs: 2365-709X

Abstract

Abstract: Miniaturization and minimization of mechanical mismatch in neural probes have been two well‐proven directions in suppressing immune response and improving spatial resolution for neuronal stimulations and recordings. While the high impedance brought by the miniaturization of electrodes has been addressed by using conductive polymers coatings in multiple reports, the stiffness of such coatings remains orders of magnitude higher than that of the brain tissue. Here, a flat neural probe based on a highly flexible microelectrode array with electrodeposited hydrogel coatings poly(2‐hydroxyethyl methacrylate) (pHEMA) and conductive polymer poly(3, 4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS), with a cross‐section area at only 300 µ m × 2.5 µ m is presented. The PEDOT/PSS coating provides a low interfacial impedance, and the pHEMA deposition bridges the mechanical mismatch between the probe and the brain tissues. The two layers of polymers modification enhance the signal‐to‐noise ratio and allow the microelectrodes array to be engineered for both recording and stimulation purposes. Besides, in vivo testing of microelectrode arrays implanted in rat hippocampus confirms a high senstivity in neural signal recording and excellent charge injection capacity which can induce long‐term potentiation in neural activities in the hippocampus. The probes provide a robust and low‐cost solution to the brain interfaces problem. Abstract : Flexible multichannel neural probe with PEDOT/PSS/pHEMA coatings is developed for in vivo neuronal stimulation and sensing. Electropolymerization of PEDOT/PSS and pHEMA on gold electrodes provides low impedance and large charge injection capacity and bridges the gap of Young's Modulus between hard electrodes and brain tissue. The fabricated probe provides an advanced device for neuroelectrophysiological investigations.