Article
Flexible 3D microelectrode arrays with high-aspect ratio electrodes for neuronal recordings
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Authors
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Simon Decke
- Institute of Biological Information Processing (IBI-3) – Bioelectronics, Forschungszentrum Jülich, Germany; RWTH Aachen University, Germany
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M. Jung
- Institute of Biological Information Processing (IBI-3) – Bioelectronics, Forschungszentrum Jülich, Germany; RWTH Aachen University, Germany
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J. Abu Shihada
- Institute of Biological Information Processing (IBI-3) – Bioelectronics, Forschungszentrum Jülich, Germany; RWTH Aachen University, Germany
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L. Koschinski
- Institute of Biological Information Processing (IBI-3) – Bioelectronics, Forschungszentrum Jülich, Germany; RWTH Aachen University, Germany; Helmholtz Nano Facility (HNF), Forschungszentrum Jülich, Germany
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S. Musall
- Institute of Biological Information Processing (IBI-3) – Bioelectronics, Forschungszentrum Jülich, Germany; RWTH Aachen University, Germany; Faculty of Medicine, Institute of Experimental Epileptology and Cognition Research, University of Bonn, Germany; University Hospital Bonn, Germany
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V. Rincón Montes
- Institute of Biological Information Processing (IBI-3) – Bioelectronics, Forschungszentrum Jülich, Germany
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A. Offenhäusser
- Institute of Biological Information Processing (IBI-3) – Bioelectronics, Forschungszentrum Jülich, Germany
| Published: | May 9, 2025 |
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Outline
Text
Objective: Current neural interfaces targeting deep intraneural regions involve numerous complex manufacturing steps and large cross-sectional footprints, which often trigger foreign body reactions due to their rigid materials. To overcome this, we have recently developed a 3D penetrating, flexible, implantable microelectrode array (MEA) capable of interfacing with different neuronal tissues [1]. To further enhance their potential, we expanded the electrode height to interface with deeper neural layers.
Materials and Methods: 3D flexible MEAs are fabricated by combining Two-Photon Polymerization, thin film technologies and template-assisted electrodeposition. This combination allows to build MEAs on different substrate materials while customizing the design in shape, pitch, and height to the needs of different neural applications. The design has been optimized for cross-section and stability using COMSOL Multiphysics, while the electrodeposition process was refined through a parameter sweep.
Results: MEAs with 3D electrodes, featuring aspect ratios up to 33:1 and pillar heights of up to 400 µm, were successfully tested in various rodent tissues, from ex vivo retinal explants to the in vivo somatosensory cortex. Further design optimizations have achieved pillar heights in the millimeter range and aspect ratios up to 44:1, with successful fabrication of these electrodes.
Discussion: The increased aspect ratio enables access to deep neural regions while maintaining a small cross-section and minimizing implantation trauma. This work, combined with appropriate implantation methods, paves the way for interfacing both thin and deep neural layers, such as the retina and cortical regions, and supports the transfer of this technology to larger animal models.
References
- 1.
- Abu Shihada J, Jung M, Decke S, Koschinski L, Musall S, Rincón Montes V, Offenhäusser A. Highly Customizable 3D Microelectrode Arrays for In Vitro and In Vivo Neuronal Tissue Recordings. Adv Sci. 2024;11: 2305944. DOI: 10.1002/advs.202305944
