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In vitro recording and stimulation performance of multi-electrode arrays passivated with plasma-enhanced atomic layer-deposited metal oxides
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- Authors
- Yong Hee Kim, Jaehee Lee, Jung Wook Lim, Kukjoo Kim, Dae Hyun Ahn, Congqi Yang, Seongjun Park, Min Sun Kim, Sang-Don Jung
- Issue Date
- 2025-04
- Citation
- Nanoscale, v.17, no.14, pp.8731-8740
- ISSN
- 2040-3364
- Publisher
- Royal Society of Chemistry
- Language
- English
- Type
- Journal Article
- Abstract
- To achieve an intimate contact between neuronal cells and the electrode in non-invasive platforms intended for neurological research, in this study, we fabricated a raised-type Au multi-electrode array (MEA) by employing nanoscale-thick indium-tin oxide (ITO; 50 nm) as a track layer and plasma-enhanced atomic layer-deposited (PEALD) Al2O3 (30-60 nm) and HfO2 (20 nm) as passivation layers. The PEALD Al2O3-passivated Au MEA was subsequently modified with electrodeposited AuPt nanoparticles (NPs) and IrOx to demonstrate the passivation capability and chemical resistance of Al2O3 to Au-, Pt-, and IrOx NP-containing electrolytes. Al2O3-passivated and IrOx/AuPt-modified MEAs could resolve optogenetically activated spikes and spontaneous activities with a root-mean-square noise level of 2.8 ± 0.3 μV generated by the primarily cultured hippocampal neurons transfected with viral vectors. PEALD Al2O3 exhibited a poor resistance to the Ag leaching environment (concentrated nitric acid maintained at 70 °C); therefore, a nanoporous Au (NPG) structure could not be implemented on the Au MEA passivated with Al2O3. By depositing a 20 nm-thick HfO2 over a 40 nm-thick Al2O3 layer, the NPG structure could be implemented on the Au MEA, confirming the chemical resistance of HfO2 to the Ag leaching environment. The nontoxicity of Al2O3 and HfO2 was confirmed by the successful primary culture of dissociated hippocampal neurons and electrophysiological studies performed using a hippocampal slice. Considering the advances in ALD technology and the vast number of metal oxides, these results extend the application of ALD metal oxides from water barriers for biomedical implants to passivation layers for in vitro MEAs.
- KSP Keywords
- 20 nm, 40 nm, Ag leaching, Chemical resistance, Deposited metal, Hippocampal neurons, Hippocampal slice, Indium Tin Oxide(ITO), Intimate contact, Metal-oxide(MOX), Multi-electrode array