Laser-patterned epoxy-based 3D microelectrode arrays for extracellular recording

• Published in: Nanoscale Vol. 16; no. 30; pp. 14295 - 14301
• Main Authors: Peng, Hu, Kopic, Inola, Potfode, Shivani Ratnakar, Teshima, Tetsuhiko F, Boustani, George Al, Hiendlmeier, Lukas, Wang, Chen, Hussain, Mian Zahid, Özkale, Berna, Fischer, Roland A, Wolfrum, Bernhard
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 07.08.2024
• Subjects: Arrays; Electrochemical impedance spectroscopy; Electrodes; Insulation; Laser ablation; Laser arrays; Lasers; Microelectrodes; Recording
• ISSN: 2040-3364; 2040-3372; 2040-3372
• DOI: 10.1039/d4nr01727g

Microelectrode arrays are commonly used to study the electrophysiological behavior of cells. Recently, there has been a growing interest in fabricating three-dimensional microelectrode arrays. Here, we present a novel process for the fast fabrication of epoxy-based 3D microelectrode array platforms with the assistance of laser-patterning technology. To this end, we photopatterned 3D pillars as scaffolds using epoxy-based dry films. Electrodes and conductor traces were fabricated by laser patterning of sputtered platinum films on top of the 3D structures, followed by deposition of parylene-C for insulation. Microelectrodes at the tip of the 3D structures were exposed using a vertical laser ablation process. The final electrodes demonstrated a low impedance of ∼10 kΩ at 1 kHz in electrochemical impedance spectroscopy measurements under physiological conditions. We investigated the maximum compression force of the 3D structures, which could withstand approximately 0.6 N per pillar. The 3D microelectrode arrays were used to record extracellular signals from HL-1 cells in culture as a proof of principle. Our results show regular firing of action potentials recorded at the tip of the 3D structures, demonstrating the possibility of recording cell signals in non-planar environments.