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Gupta B, Kepros B, Landgraf JB, Becker MF, Li W, Purcell EK, Siegenthaler JR. All-Diamond Boron-Doped Microelectrodes for Neurochemical Sensing with Fast-Scan Cyclic Voltammetry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.07.606919. [PMID: 39211237 PMCID: PMC11360963 DOI: 10.1101/2024.08.07.606919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Neurochemical sensing with implantable devices has gained remarkable attention over the last few decades. A promising area of this research is the progress of novel electrodes as electrochemical tools for neurotransmitter detection in the brain. The boron-doped diamond (BDD) electrode is one such candidate that previously has been reported for its excellent electrochemical properties, including a wide working potential, superior chemical inertness and mechanical stability, good biocompatibility and resistance to fouling. Meanwhile, limited research has been conducted on the BDD as a microelectrode for neurochemical detection. Our team has developed a freestanding, all diamond microelectrode consisting of a boron-doped polycrystalline diamond core, encapsulated in an insulating polycrystalline diamond shell, with a cleaved planar tip for electrochemical sensing. This all-diamond electrode is advantageous due to its - (1) batch fabrication using wafer technology that eliminates traditional hand fabrication errors and inconsistencies, (2) absence of metal-based wires, or foundations, to improve biocompatibility and flexibility, and (3) sp 3 carbon surface with resistance to biofouling, i.e. adsorption of proteins or unwanted molecules at the electrode surface in a biological environment that impedes overall electrode performance. Here, we provide findings on further in vitro testing and development of the freestanding boron-doped diamond microelectrode (BDDME) for neurotransmitter detection using fast scan cyclic voltammetry (FSCV). In this report, we elaborate on - 1) an updated fabrication scheme and work flow to generate all diamond BDDMEs, 2) slow scan cyclic voltammetry measurements of reference and target analytes to understand basic electrochemical behavior of the electrode, and 3) FSCV characterization of common neurotransmitters, and overall favorability of serotonin (5-HT) detection. The BDDME showed a 2-fold increased FSCV response for 5-HT in comparison to dopamine (DA), with a limit of detection of 0.16 µM for 5-HT and 0.26 µM for DA. These results are intended to expand on the development of the next generation BDDME and guide future in vivo experiments, adding to the growing body of literature on implantable devices for neurochemical sensing.
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Kwon YW, Ahn DB, Park YG, Kim E, Lee DH, Kim SW, Lee KH, Kim WY, Hong YM, Koh CS, Jung HH, Chang JW, Lee SY, Park JU. Power-integrated, wireless neural recording systems on the cranium using a direct printing method for deep-brain analysis. SCIENCE ADVANCES 2024; 10:eadn3784. [PMID: 38569040 PMCID: PMC10990281 DOI: 10.1126/sciadv.adn3784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 02/27/2024] [Indexed: 04/05/2024]
Abstract
Conventional power-integrated wireless neural recording devices suffer from bulky, rigid batteries in head-mounted configurations, hindering the precise interpretation of the subject's natural behaviors. These power sources also pose risks of material leakage and overheating. We present the direct printing of a power-integrated wireless neural recording system that seamlessly conforms to the cranium. A quasi-solid-state Zn-ion microbattery was 3D-printed as a built-in power source geometrically synchronized to the shape of a mouse skull. Soft deep-brain neural probes, interconnections, and auxiliary electronics were also printed using liquid metals on the cranium with high resolutions. In vivo studies using mice demonstrated the reliability and biocompatibility of this wireless neural recording system, enabling the monitoring of neural activities across extensive brain regions without notable heat generation. This all-printed neural interface system revolutionizes brain research, providing bio-conformable, customizable configurations for improved data quality and naturalistic experimentation.
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Affiliation(s)
- Yong Won Kwon
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
| | - David B. Ahn
- Department of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Young-Geun Park
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
| | - Enji Kim
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
| | - Dong Ha Lee
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
| | - Sang-Woo Kim
- Department of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Kwon-Hyung Lee
- Ulsan Advanced Energy Technology R&D Center, Korea Institute of Energy Research (KIER), Ulsan 44776, Republic of Korea
| | - Won-Yeong Kim
- Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 03772, Republic of Korea
| | - Yeon-Mi Hong
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
| | - Chin Su Koh
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Hyun Ho Jung
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Jin Woo Chang
- Department of Neurosurgery, Korea University Anam Hospital, Seoul 02841, Republic of Korea
| | - Sang-Young Lee
- Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 03772, Republic of Korea
| | - Jang-Ung Park
- Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
- Graduate Program of Nano Biomedical Engineering (NanoBME), Advanced Science Institute, Yonsei University, Seoul 03722, Republic of Korea
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Faul EBA, Broussard AM, Rivera DR, Pwint MY, Wu B, Cao Q, Bailey D, Cui XT, Castagnola E. Batch Fabrication of Microelectrode Arrays with Glassy Carbon Microelectrodes and Interconnections for Neurochemical Sensing: Promises and Challenges. MICROMACHINES 2024; 15:277. [PMID: 38399004 PMCID: PMC10892456 DOI: 10.3390/mi15020277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/07/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024]
Abstract
Flexible multielectrode arrays with glassy carbon (GC) electrodes and metal interconnection (hybrid MEAs) have shown promising performance in multi-channel neurochemical sensing. A primary challenge faced by hybrid MEAs fabrication is the adhesion of the metal traces with the GC electrodes, as prolonged electrical and mechanical stimulation can lead to adhesion failure. Previous devices with GC electrodes and interconnects made of a homogeneous material (all GC) demonstrated exceptional electrochemical stability but required miniaturization for enhanced tissue integration and chronic electrochemical sensing. In this study, we used two different methods for the fabrication of all GC-MEAs on thin flexible substrates with miniaturized features. The first method, like that previously reported, involves a double pattern-transfer photolithographic process, including transfer-bonding on temporary polymeric support. The second method requires a double-etching process, which uses a 2 µm-thick low stress silicon nitride coating of the Si wafer as the bottom insulator layer for the MEAs, bypassing the pattern-transfer and demonstrating a novel technique with potential advantages. We confirmed the feasibility of the two fabrication processes by verifying the practical conductivity of 3 µm-wide 2 µm-thick GC traces, the GC microelectrode functionality, and their sensing capability for the detection of serotonin using fast scan cyclic voltammetry. Through the exchange and discussion of insights regarding the strengths and limitations of these microfabrication methods, our goal is to propel the advancement of GC-based MEAs for the next generation of neural interface devices.
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Affiliation(s)
- Emma-Bernadette A. Faul
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
| | - Austin M. Broussard
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
| | - Daniel R. Rivera
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
| | - May Yoon Pwint
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Bingchen Wu
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Qun Cao
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
| | - Davis Bailey
- Institute for Micromanufacturing, Louisiana Tech University, Ruston, LA 15213, USA;
| | - X. Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219-3110, USA
| | - Elisa Castagnola
- Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA; (E.-B.A.F.); (A.M.B.); (D.R.R.)
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (M.Y.P.); (B.W.); (Q.C.); (X.T.C.)
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Wang Q, Li Z, Nie D, Mu X, Wang Y, Jiang Y, Zhang Y, Lu Z. Low-frequency electroacupuncture exerts antinociceptive effects through activation of POMC neural circuit induced endorphinergic input to the periaqueductal gray from the arcuate nucleus. Mol Pain 2024; 20:17448069241254201. [PMID: 38670551 PMCID: PMC11102703 DOI: 10.1177/17448069241254201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 03/12/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
It has been widely recognized that electroacupuncture (EA) inducing the release of β-endorphin represents a crucial mechanism of EA analgesia. The arcuate nucleus (ARC) in the hypothalamus is a vital component of the endogenous opioid peptide system. Serving as an integration center, the periaqueductal gray (PAG) receives neural fiber projections from the frontal cortex, insular cortex, and ARC. However, the specific mechanisms how EA facilitates the release of β-endorphin within the ARC, eliciting analgesic effects are yet to be elucidated. In this study, we conducted in vivo and in vitro experiments by transcriptomics, microdialysis, photogenetics, chemical genetics, and calcium imaging, combined with transgenic animals. Firstly, we detected 2 Hz EA at the Zusanli (ST36) increased the level of β-endorphin and transcriptional level of proopiomelanocortin (POMC). Our transcriptomics profiling demonstrated that 2 Hz EA at the ST36 modulates the expression of c-Fos and Jun B in ARC brain nuclear cluster, and the transcriptional regulation of 2 Hz EA mainly occur in POMC neurons by Immunofluorescence staining verification. Meaning while, 2 Hz EA specifically activated the cAMP-PKA-CREB signaling pathway in ARC which mediating the c-Fos and Jun B transcription, and 2 Hz EA analgesia is dependent on the activation of cAMP-PKA-CREB signaling pathway in ARC. In order to investigate how the β-endorphin produced in ARC transfer to integration center PAG, transneuronal tracing technology was used to observe the 2 Hz EA promoted the neural projection from ARC to PAG compared to 100 Hz EA and sham mice. Inhibited PAGGABA neurons, the transfer of β-endorphin from the ARC nucleus to the PAG nucleus through the ARCPOMC-PAGGABA neural circuit. Furthermore, by manipulating the excitability of POMC neurons from ARCPOMC to PAGGABA using inhibitory chemogenetics and optogenetics, we found that this inhibition significantly reduced transfer of β-endorphin from the ARC nucleus to the PAG nucleus and the effectiveness of 2 Hz EA analgesia in neurological POMC cyclization recombination enzyme (Cre) mice and C57BL/6J mice, which indicates that the transfer of β-endorphin depends on the activation of POMC neurons prefect from ARCPOMC to PAGGABA. These findings contribute to our understanding of the neural circuitry underlying the EA pain-relieving effects and maybe provide valuable insights for optimizing EA stimulation parameters in clinical pain treatment using the in vivo dynamic visual investigating the central analgesic mechanism.
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Affiliation(s)
- Qian Wang
- Shandong University of Traditional Chinese Medicine, Nanjing, China
| | - Zhonghao Li
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence Research, Peking University, Beijing, China
- School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
- Key Laboratory of Acupuncture and Medicine Research of Ministry of Education, Nanjing University of Chinese Medicine, Nanjing, China
- School of Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Dengyun Nie
- Key Laboratory of Acupuncture and Medicine Research of Ministry of Education, Nanjing University of Chinese Medicine, Nanjing, China
- School of Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Xinru Mu
- Key Laboratory of Acupuncture and Medicine Research of Ministry of Education, Nanjing University of Chinese Medicine, Nanjing, China
- School of Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yuxuan Wang
- Key Laboratory of Acupuncture and Medicine Research of Ministry of Education, Nanjing University of Chinese Medicine, Nanjing, China
- School of Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yongwei Jiang
- Key Laboratory of Acupuncture and Medicine Research of Ministry of Education, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yongchen Zhang
- Shandong University of Traditional Chinese Medicine, Nanjing, China
| | - Zhigang Lu
- Key Laboratory of Acupuncture and Medicine Research of Ministry of Education, Nanjing University of Chinese Medicine, Nanjing, China
- School of Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
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Popa RC, Serban CA, Barborica A, Zagrean AM, Buiu O, Dumbravescu N, Paslaru AC, Obreja C, Pachiu C, Stoian M, Marculescu C, Radoi A, Vulpe S, Ion M. Functional Enhancement and Characterization of an Electrophysiological Mapping Electrode Probe with Carbonic, Directional Macrocontacts. SENSORS (BASEL, SWITZERLAND) 2023; 23:7497. [PMID: 37687953 PMCID: PMC10490806 DOI: 10.3390/s23177497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/16/2023] [Accepted: 08/21/2023] [Indexed: 09/10/2023]
Abstract
Electrophysiological mapping (EM) using acute electrode probes is a common procedure performed during functional neurosurgery. Due to their constructive specificities, the EM probes are lagging in innovative enhancements. This work addressed complementing a clinically employed EM probe with carbonic and circumferentially segmented macrocontacts that are operable both for neurophysiological sensing ("recording") of local field potentials (LFP) and for test stimulation. This paper illustrates in-depth the development that is based on the direct writing of functional materials. The unconventional fabrication processes were optimized on planar geometry and then transferred to the cylindrically thin probe body. We report and discuss the constructive concept and architecture of the probe, characteristics of the electrochemical interface deduced from voltammetry and chronopotentiometry, and the results of in vitro and in vivo recording and pulse stimulation tests. Two- and three-directional macrocontacts were added on probes having shanks of 550 and 770 μm diameters and 10-23 cm lengths. The graphitic material presents a ~2.7 V wide, almost symmetric water electrolysis window, and an ultra-capacitive charge transfer. When tested with clinically relevant 150 μs biphasic current pulses, the interfacial polarization stayed safely away from the water window for pulse amplitudes up to 9 mA (135 μC/cm2). The in vivo experiments on adult rat models confirmed the high-quality sensing of LFPs. Additionally, the in vivo-prevailing increase in the electrode impedance and overpotential are discussed and modeled by an ionic mobility-reducing spongiform structure; this restricted diffusion model gives new applicative insight into the in vivo-uprisen stimulation overpotential.
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Affiliation(s)
- Radu C. Popa
- National Institute for R&D in Microtechnologies–IMT Bucharest, 077190 Bucharest, Romania; (O.B.); (N.D.); (C.O.); (C.P.); (M.S.); (C.M.); (A.R.); (S.V.); (M.I.)
| | - Cosmin-Andrei Serban
- Termobit Prod Srl, 020281 Bucharest, Romania; (C.-A.S.); (A.B.)
- Fhc, Inc., Bowdoin, ME 04287, USA
- Faculty of Physics, University of Bucharest, 077125 Magurele, Romania
| | - Andrei Barborica
- Termobit Prod Srl, 020281 Bucharest, Romania; (C.-A.S.); (A.B.)
- Fhc, Inc., Bowdoin, ME 04287, USA
- Faculty of Physics, University of Bucharest, 077125 Magurele, Romania
| | - Ana-Maria Zagrean
- Physiology and Neuroscience Department, “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania; (A.-M.Z.); (A.-C.P.)
| | - Octavian Buiu
- National Institute for R&D in Microtechnologies–IMT Bucharest, 077190 Bucharest, Romania; (O.B.); (N.D.); (C.O.); (C.P.); (M.S.); (C.M.); (A.R.); (S.V.); (M.I.)
| | - Niculae Dumbravescu
- National Institute for R&D in Microtechnologies–IMT Bucharest, 077190 Bucharest, Romania; (O.B.); (N.D.); (C.O.); (C.P.); (M.S.); (C.M.); (A.R.); (S.V.); (M.I.)
| | - Alexandru-Catalin Paslaru
- Physiology and Neuroscience Department, “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania; (A.-M.Z.); (A.-C.P.)
| | - Cosmin Obreja
- National Institute for R&D in Microtechnologies–IMT Bucharest, 077190 Bucharest, Romania; (O.B.); (N.D.); (C.O.); (C.P.); (M.S.); (C.M.); (A.R.); (S.V.); (M.I.)
| | - Cristina Pachiu
- National Institute for R&D in Microtechnologies–IMT Bucharest, 077190 Bucharest, Romania; (O.B.); (N.D.); (C.O.); (C.P.); (M.S.); (C.M.); (A.R.); (S.V.); (M.I.)
| | - Marius Stoian
- National Institute for R&D in Microtechnologies–IMT Bucharest, 077190 Bucharest, Romania; (O.B.); (N.D.); (C.O.); (C.P.); (M.S.); (C.M.); (A.R.); (S.V.); (M.I.)
| | - Catalin Marculescu
- National Institute for R&D in Microtechnologies–IMT Bucharest, 077190 Bucharest, Romania; (O.B.); (N.D.); (C.O.); (C.P.); (M.S.); (C.M.); (A.R.); (S.V.); (M.I.)
| | - Antonio Radoi
- National Institute for R&D in Microtechnologies–IMT Bucharest, 077190 Bucharest, Romania; (O.B.); (N.D.); (C.O.); (C.P.); (M.S.); (C.M.); (A.R.); (S.V.); (M.I.)
| | - Silviu Vulpe
- National Institute for R&D in Microtechnologies–IMT Bucharest, 077190 Bucharest, Romania; (O.B.); (N.D.); (C.O.); (C.P.); (M.S.); (C.M.); (A.R.); (S.V.); (M.I.)
| | - Marian Ion
- National Institute for R&D in Microtechnologies–IMT Bucharest, 077190 Bucharest, Romania; (O.B.); (N.D.); (C.O.); (C.P.); (M.S.); (C.M.); (A.R.); (S.V.); (M.I.)
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Castagnola E, Robbins EM, Krahe DD, Wu B, Pwint MY, Cao Q, Cui XT. Stable in-vivo electrochemical sensing of tonic serotonin levels using PEDOT/CNT-coated glassy carbon flexible microelectrode arrays. Biosens Bioelectron 2023; 230:115242. [PMID: 36989659 PMCID: PMC10101938 DOI: 10.1016/j.bios.2023.115242] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/13/2023] [Accepted: 03/19/2023] [Indexed: 03/29/2023]
Abstract
Chronic sampling of tonic serotonin (5-hydroxytryptamine, 5-HT) concentrations in the brain is critical for tracking neurological disease development and the time course of pharmacological treatments. Despite their value, in vivo chronic multi-site measurements of tonic 5-HT have not been reported. To fill this technological gap, we batch-fabricated implantable glassy carbon (GC) microelectrode arrays (MEAs) onto a flexible SU-8 substrate to provide an electrochemically stable and biocompatible device/tissue interface. To achieve detection of tonic 5-HT concentrations, we applied a poly(3,4-ethylenedioxythiophene)/carbon nanotube (PEDOT/CNT) electrode coating and optimized a square wave voltammetry (SWV) waveform for selective 5-HT measurement. In vitro, the PEDOT/CNT-coated GC microelectrodes achieved high sensitivity to 5-HT, good fouling resistance, and excellent selectivity against the most common neurochemical interferents. In vivo, our PEDOT/CNT-coated GC MEAs successfully detected basal 5-HT concentrations at different locations within the CA2 region of the hippocampus of both anesthetized and awake mice. Furthermore, the PEDOT/CNT-coated MEAs were able to detect tonic 5-HT in the mouse hippocampus for one week after implantation. Histology reveals that the flexible GC MEA implants caused less tissue damage and reduced inflammatory response in the hippocampus compared to commercially available stiff silicon probes. To the best of our knowledge, this PEDOT/CNT-coated GC MEA is the first implantable, flexible sensor capable of chronic in vivo multi-site sensing of tonic 5-HT.
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Affiliation(s)
- Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, PA 15260, Pittsburgh, PA, USA; Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA, 818 Nelson Ave, 71272, USA
| | - Elaine M Robbins
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, PA 15260, Pittsburgh, PA, USA
| | - Daniela D Krahe
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, PA 15260, Pittsburgh, PA, USA
| | - Bingchen Wu
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, PA 15260, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, 4400 Fifth Ave, PA 15213, Pittsburgh, PA, 15261, USA
| | - May Yoon Pwint
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, PA 15260, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, University of Pittsburgh, 4400 Fifth Ave, PA 15213, Pittsburgh, PA, 15261, USA
| | - Qun Cao
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, PA 15260, Pittsburgh, PA, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, PA 15260, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA, 15219-3110, USA; Center for Neural Basis of Cognition, University of Pittsburgh, 4400 Fifth Ave, PA 15213, Pittsburgh, PA, 15261, USA.
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7
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Hollow ring-like flexible electrode architecture enabling subcellular multi-directional neural interfacing. Biosens Bioelectron 2023; 227:115182. [PMID: 36870146 DOI: 10.1016/j.bios.2023.115182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/20/2023] [Accepted: 02/23/2023] [Indexed: 02/27/2023]
Abstract
Implantable neural microelectrodes for recording and stimulating neural activity are critical for research in neuroscience and clinical neuroprosthetic applications. A current need exists for developing new technological solutions for obtaining highly selective and stealthy electrodes that provide reliable neural integration and maintain neuronal viability. This paper reports a novel Hollow Ring-like type electrode to sense and/or stimulate neural activity from three-dimensional neural networks. Due to its unique design, the ring electrode architecture enables easy and reliable access of the electrode to three-dimensional neural networks with reduced mechanical contact on the biological tissue, while providing improved electrical interface with cells. The Hollow Ring electrodes, particularly when coated with the conducting polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), show improved electrical properties with extremely low impedance (7 MΩ μm2) and high charge injection capabilities (15 mC/cm2), when compared to traditional planar disk-type electrodes. The ring design also serves as an optimal architecture for cell growth to create an optimal subcellular electrical-neural interface. In addition, we showed that neural signals recorded by the ring electrode were better resolved than recordings from a traditional disk-type electrode improving the signal-to-noise ratio (SNR) and the burst detection from 3D neuronal networks in vitro. Overall, our results suggest the great potential of the hollow ring design for developing next-generation microelectrodes for applications in neural interfaces used in physiological studies and neuromodulation applications.
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8
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Sun T, Tsaava T, Peragine J, Crosfield C, Lopez MF, Modi R, Sharma R, Li C, Sohal H, Chang EH, Rieth L. Flexible IrO x neural electrode for mouse vagus nerve stimulation. Acta Biomater 2023; 159:394-409. [PMID: 36669547 PMCID: PMC10823593 DOI: 10.1016/j.actbio.2023.01.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 12/26/2022] [Accepted: 01/10/2023] [Indexed: 01/19/2023]
Abstract
Vagus nerve stimulation (VNS) is being actively explored as a treatment for multiple conditions as part of bioelectronic medicine research. Reliable and safe VNS in mouse models is a critical need for understanding mechanisms of these. We report on the development and evaluation of a microfabricated cuff electrode (MouseFlex) constructed of polyimide (PI) and with iridium oxide (IrOx) electrodes that is thermoformed to 86 µm ± 12 µm radius to interface the mouse cervical vagus nerve (r ≈ 50 µm). Innovative bench-top methods were used to evaluate the stimulation stability and electrochemical properties of electrodes. Our aggressive stimulation stability (Stim-Stab) test utilized 1 billion pulses at a 1000 Hz with a current density of 6.28 A/cm2 (1.51 mC/cm2/phase) delivering 3023 × 103 C/cm2 to evaluate electrode lifetimes, and all electrodes remained functional. We also investigated the effects of thermoforming on their impedance, charge storage capacity (CSC), and charge injection capacity (CIC). The modest changes in electrochemical properties indicate that the thermoforming process was well tolerated. Thermoformed electrode safety and efficacy were evaluated in-vivo by performing acute VNS in mice and monitoring their heart and respiration rate as biomarkers. Their electrochemical properties were also measured before, during and after VNS. Bradycardia and bradypnea were reliably induced at stimulation currents of 100 to 200 µA, well below the in-vivo CIC of ∼1250 µA (∼0.5 mC/cm2), supporting their safety and efficacy. The electrode impedance increased and CIC decreased during in-vivo use, but largely reversed these changes in in-vitro testing after enzymatic cleaning, supporting their tolerance for surgical use. STATEMENT OF SIGNIFICANCE: Vagus nerve stimulation (VNS) is a rapidly growing aspect of healthcare and bioelectronic medicine research. Reliable and safe VNS in mice with small diameter (d ≈ 100 µm) nerves has been a challenge due to achieving intimate contact with the nerve, and the stimulation stability of commonly used electrodes. We demonstrate a microfabricated (MouseFlex) cuff electrode constructed of polyimide with IrOx electrodes that is thermoformed to contact the mouse cervical vagus. Bench studies highlight the stimulation stability exceeded 109 pulses at 6.28 A/cm2 and their electrochemical properties were measured before, during, and after bench and nerve stimulation. Nerve stimulation induced bradycardia and bradypnea at currents below the in-vivo charge injection capacity, supporting their safety, efficacy, and tolerance for surgical handling.
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Affiliation(s)
- Tao Sun
- Mechanical & Aerospace Engineering Department, Benjamin M. Statler College of Engineering & Mineral Resources, West Virginia University, Morgantown, WV 26505, United States
| | - Téa Tsaava
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | - Joanne Peragine
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | - Christine Crosfield
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | | | - Romil Modi
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | - Rohit Sharma
- Electrical and Computer Engineering Department, University of Utah, Salt Lake City, UT 84112, United States; Applied Biosensors, Salt Lake City, UT 84115, United States
| | - Chunyan Li
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | | | - Eric H Chang
- Institute of Bioelectronic Medicine, Feinstein Institutes for Medical Research, Manhasset, New York 11030, United States
| | - Loren Rieth
- Mechanical & Aerospace Engineering Department, Benjamin M. Statler College of Engineering & Mineral Resources, West Virginia University, Morgantown, WV 26505, United States.
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9
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Da Y, Luo S, Tian Y. Real-Time Monitoring of Neurotransmitters in the Brain of Living Animals. ACS APPLIED MATERIALS & INTERFACES 2023; 15:138-157. [PMID: 35394736 DOI: 10.1021/acsami.2c02740] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Neurotransmitters, as important chemical small molecules, perform the function of neural signal transmission from cell to cell. Excess concentrations of neurotransmitters are often closely associated with brain diseases, such as Alzheimer's disease, depression, schizophrenia, and Parkinson's disease. On the other hand, the release of neurotransmitters under the induced stimulation indicates the occurrence of reward-related behaviors, including food and drug addiction. Therefore, to understand the physiological and pathological functions of neurotransmitters, especially in complex environments of the living brain, it is urgent to develop effective tools to monitor their dynamics with high sensitivity and specificity. Over the past 30 years, significant advances in electrochemical sensors and optical probes have brought new possibilities for studying neurons and neural circuits by monitoring the changes in neurotransmitters. This Review focuses on the progress in the construction of sensors for in vivo analysis of neurotransmitters in the brain and summarizes current attempts to address key issues in the development of sensors with high selectivity, sensitivity, and stability. Combined with the latest advances in technologies and methods, several strategies for sensor construction are provided for recording chemical signal changes in the complex environment of the brain.
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Affiliation(s)
- Yifan Da
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
| | - Shihua Luo
- Department of Traumatology, Rui Jin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Yang Tian
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai 200241, China
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10
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Xu M, Zhao Y, Xu G, Zhang Y, Sun S, Sun Y, Wang J, Pei R. Recent Development of Neural Microelectrodes with Dual-Mode Detection. BIOSENSORS 2022; 13:59. [PMID: 36671894 PMCID: PMC9856135 DOI: 10.3390/bios13010059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/24/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
Neurons communicate through complex chemical and electrophysiological signal patterns to develop a tight information network. A physiological or pathological event cannot be explained by signal communication mode. Therefore, dual-mode electrodes can simultaneously monitor the chemical and electrophysiological signals in the brain. They have been invented as an essential tool for brain science research and brain-computer interface (BCI) to obtain more important information and capture the characteristics of the neural network. Electrochemical sensors are the most popular methods for monitoring neurochemical levels in vivo. They are combined with neural microelectrodes to record neural electrical activity. They simultaneously detect the neurochemical and electrical activity of neurons in vivo using high spatial and temporal resolutions. This paper systematically reviews the latest development of neural microelectrodes depending on electrode materials for simultaneous in vivo electrochemical sensing and electrophysiological signal recording. This includes carbon-based microelectrodes, silicon-based microelectrode arrays (MEAs), and ceramic-based MEAs, focusing on the latest progress since 2018. In addition, the structure and interface design of various types of neural microelectrodes have been comprehensively described and compared. This could be the key to simultaneously detecting electrochemical and electrophysiological signals.
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Affiliation(s)
- Meng Xu
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
| | - Yuewu Zhao
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
| | - Guanghui Xu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
| | - Yuehu Zhang
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
| | - Shengkai Sun
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
| | - Yan Sun
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
| | - Jine Wang
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
| | - Renjun Pei
- CAS Key Laboratory for Nano-Bio Interface, Division of Nano-biomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215123, China
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China (USTC), Hefei 230026, China
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11
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Castagnola E, Robbins EM, Wu B, Pwint MY, Garg R, Cohen-Karni T, Cui XT. Flexible Glassy Carbon Multielectrode Array for In Vivo Multisite Detection of Tonic and Phasic Dopamine Concentrations. BIOSENSORS 2022; 12:540. [PMID: 35884343 PMCID: PMC9312827 DOI: 10.3390/bios12070540] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 07/13/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
Dopamine (DA) plays a central role in the modulation of various physiological brain functions, including learning, motivation, reward, and movement control. The DA dynamic occurs over multiple timescales, including fast phasic release, as a result of neuronal firing and slow tonic release, which regulates the phasic firing. Real-time measurements of tonic and phasic DA concentrations in the living brain can shed light on the mechanism of DA dynamics underlying behavioral and psychiatric disorders and on the action of pharmacological treatments targeting DA. Current state-of-the-art in vivo DA detection technologies are limited in either spatial or temporal resolution, channel count, longitudinal stability, and ability to measure both phasic and tonic dynamics. We present here an implantable glassy carbon (GC) multielectrode array on a SU-8 flexible substrate for integrated multichannel phasic and tonic measurements of DA concentrations. The GC MEA demonstrated in vivo multichannel fast-scan cyclic voltammetry (FSCV) detection of electrically stimulated phasic DA release simultaneously at different locations of the mouse dorsal striatum. Tonic DA measurement was enabled by coating GC electrodes with poly(3,4-ethylenedioxythiophene)/carbon nanotube (PEDOT/CNT) and using optimized square-wave voltammetry (SWV). Implanted PEDOT/CNT-coated MEAs achieved stable detection of tonic DA concentrations for up to 3 weeks in the mouse dorsal striatum. This is the first demonstration of implantable flexible MEA capable of multisite electrochemical sensing of both tonic and phasic DA dynamics in vivo with chronic stability.
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Affiliation(s)
- Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (E.C.); (E.M.R.); (B.W.); (M.Y.P.)
| | - Elaine M. Robbins
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (E.C.); (E.M.R.); (B.W.); (M.Y.P.)
| | - Bingchen Wu
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (E.C.); (E.M.R.); (B.W.); (M.Y.P.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - May Yoon Pwint
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (E.C.); (E.M.R.); (B.W.); (M.Y.P.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Raghav Garg
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (R.G.); (T.C.-K.)
| | - Tzahi Cohen-Karni
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (R.G.); (T.C.-K.)
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, USA; (E.C.); (E.M.R.); (B.W.); (M.Y.P.)
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
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12
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Whulanza Y, Arafat Y, Rahman S, Utomo M, Kassegne S. On-chip testing of a carbon-based platform for electro-adsorption of glutamate. Heliyon 2022; 8:e09445. [PMID: 35647339 PMCID: PMC9133582 DOI: 10.1016/j.heliyon.2022.e09445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/30/2022] [Accepted: 05/11/2022] [Indexed: 11/25/2022] Open
Abstract
It is known that excessive concentrations of glutamate in the brain can cause neurotoxicity. A common approach to neutralizing this phenomenon is the use of suppressant drugs. However, excessive dependence on suppressant drugs could potentially lead to adversarial side effects, such as drug addiction. Here, we propose an alternative approach to this problem by controlling excessive amounts of glutamate ions through carbon-based, neural implant–mediated uptake. In this study, we introduce a microfluidic system that enables us to emulate the uptake of glutamate into the carbon matrix. The uptake is controlled using electrical pulses to incorporate glutamate ions into the carbon matrix through electro-adsorption. The effect of electric potential on glutamate ion uptake to control the amount of glutamate released into the microfluidic system was observed. The glutamate concentration was measured using a Ultra Violet-Visible spectrophotometer. The current setup demonstrated that a low pulsatile electric potential (0.5–1.5 V) was able to effectively govern the uptake of glutamate ions. The stimulated carbon matrix was able to decrease glutamate concentration by up to 40%. Furthermore, our study shows that these “entrapped” glutamate molecules can be effectively released upon electrical stimulation, thereby reversing the carbon electrical charge through a process called reverse uptake. A release model was used to study the profile of glutamate release from the carbon matrix at a potential of 0–1.5 V. This study showed that a burst release of glutamate was evident at an applied voltage higher than 0.5 V. Ultimately, the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) test for cytotoxicity indicated a cell viability of more than 80% for the carbon matrix. This test demonstrates that the carbon matrix can support the proliferation of cells and has a nontoxic composition; thus, it could be accepted as a candidate material for use as neural implants.
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13
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Nam KH, Abdulhafez M, Castagnola E, Tomaraei GN, Cui XT, Bedewy M. Laser direct write of heteroatom-doped graphene on molecularly controlled polyimides for electrochemical biosensors with nanomolar sensitivity. CARBON 2022; 188:209-219. [PMID: 36101831 PMCID: PMC9467290 DOI: 10.1016/j.carbon.2021.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Fabrication of heteroatom-doped graphene electrodes remains a challenging endeavor, especially on flexible substrates. Precise chemical and morphological control is even more challenging for patterned microelectrodes. We herein demonstrate a scalable process for directly generating micropatterns of heteroatom-doped porous graphene on polyimide with different backbones using a continuous-wave infrared laser. Conventional two-step polycondensation of 4,4'-oxydianiline with three different tetracarboxylic dianhydrides enabled the fabrication of fully aromatic polyimides with various internal linkages such as phenylene, trifluoromethyl or sulfone groups. Accordingly, we leverage this laser-induced polymer-to-doped-graphene conversion for fabricating electrically conductive microelectrodes with efficient utilization of heteroatoms (N-doped, F-doped, and S-doped). Tuning laser fluence enabled achieving electrical resistivity lower than ~13 Ω sq-1 for F-doped and N-doped graphene. Finally, our microelectrodes exhibit superior performance for electrochemical sensing of dopamine, one of the important neurotransmitters in the brain. Compared with carbon fiber microelectrodes, the gold standard in electrochemical dopamine sensing, our F-doped high surface area graphene microelectrodes demonstrated 3 order of magnitude higher sensitivity per unit area, detecting dopamine concentrations as low as 10 nM with excellent reproducibility. Hence, our approach is promising for facile fabrication of microelectrodes with superior capabilities for various electrochemical and sensing applications including early diagnosis of neurological disorders.
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Affiliation(s)
- Ki-Ho Nam
- Department of Industrial Engineering, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA, 15261, USA
| | - Moataz Abdulhafez
- Department of Industrial Engineering, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA, 15261, USA
| | - Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA, 15261, USA
| | - Golnaz Najaf Tomaraei
- Department of Industrial Engineering, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA, 15261, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA, 15261, USA
| | - Mostafa Bedewy
- Department of Industrial Engineering, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA, 15261, USA
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA, 15261, USA
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA, 15261, USA
- Corresponding author. Department of Industrial Engineering, University of Pittsburgh, 3700 O’Hara Street, Pittsburgh, PA, 15261, USA. (M. Bedewy)
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14
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Vėbraitė I, Hanein Y. Soft Devices for High-Resolution Neuro-Stimulation: The Interplay Between Low-Rigidity and Resolution. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:675744. [PMID: 35047928 PMCID: PMC8757739 DOI: 10.3389/fmedt.2021.675744] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/14/2021] [Indexed: 12/27/2022] Open
Abstract
The field of neurostimulation has evolved over the last few decades from a crude, low-resolution approach to a highly sophisticated methodology entailing the use of state-of-the-art technologies. Neurostimulation has been tested for a growing number of neurological applications, demonstrating great promise and attracting growing attention in both academia and industry. Despite tremendous progress, long-term stability of the implants, their large dimensions, their rigidity and the methods of their introduction and anchoring to sensitive neural tissue remain challenging. The purpose of this review is to provide a concise introduction to the field of high-resolution neurostimulation from a technological perspective and to focus on opportunities stemming from developments in materials sciences and engineering to reduce device rigidity while optimizing electrode small dimensions. We discuss how these factors may contribute to smaller, lighter, softer and higher electrode density devices.
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Affiliation(s)
- Ieva Vėbraitė
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Yael Hanein
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
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15
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Schmidt S, Haensch T, Frank R, Jahnke HG, Robitzki AA. Reactive Sputtered Silicon Nitride as an Alternative Passivation Layer for Microelectrode Arrays in Sensitive Bioimpedimetric Cell Monitoring. ACS APPLIED MATERIALS & INTERFACES 2021; 13:59185-59195. [PMID: 34851082 DOI: 10.1021/acsami.1c14981] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Microelectrode arrays (MEAs) are widely used to study the behavior of cells noninvasively and in real time. While the design of MEAs focuses mainly on the electrode material or its application-dependent modification, the passivation layer, which is crucial to define the electrode area and to insulate the conducting paths, remains largely unnoticed. Because often most cells are in direct contact with the passivation layer rather than the electrode material, biocompatible photoresists such as SU-8 are almost exclusively used. However, SU-8 is not without limitations in terms of optical transmission, optimal cell support, or compatibility within polymer-based microfluidic lab on chip systems. Here, we established a silicon nitride (SiN) passivation by physical vapor deposition (PVD), which was optimized and evaluated for impedance spectroscopy-based monitoring of cells. Surface characteristics, biocompatibility, and electrical insulation capability were investigated and compared to SU8 in detail. To investigate the influence of the SiN passivation on the impedimetric analysis of cells, HEK-293 A and MCF-7 were chosen as adherent cell models and measured on microelectrodes of 50-200 μm in diameter. The results clearly revealed an overall suitability of SiN as alternative passivation. While for the smallest electrode size a cell line dependent comparable or slightly decreased cell signal could be observed in comparison with SU-8, a significant higher cell signal was observed for microelectrodes larger than 50 μm in diameter. Furthermore, a high suitability for the bonding of PEGDA and PDMS microfluidic structures on the SiN passivation layer without any leakage could be demonstrated.
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Affiliation(s)
- Sabine Schmidt
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Deutscher Platz 5, D-04103 Leipzig, Germany
| | - Tobias Haensch
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Deutscher Platz 5, D-04103 Leipzig, Germany
| | - Ronny Frank
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Deutscher Platz 5, D-04103 Leipzig, Germany
| | - Heinz-Georg Jahnke
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Deutscher Platz 5, D-04103 Leipzig, Germany
| | - Andrea A Robitzki
- Centre for Biotechnology and Biomedicine, Molecular Biological-Biochemical Processing Technology, Leipzig University, Deutscher Platz 5, D-04103 Leipzig, Germany
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16
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Vajrala VS, Saunier V, Nowak LG, Flahaut E, Bergaud C, Maziz A. Nanofibrous PEDOT-Carbon Composite on Flexible Probes for Soft Neural Interfacing. Front Bioeng Biotechnol 2021; 9:780197. [PMID: 34900968 PMCID: PMC8662776 DOI: 10.3389/fbioe.2021.780197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/12/2021] [Indexed: 11/25/2022] Open
Abstract
In this study, we report a flexible implantable 4-channel microelectrode probe coated with highly porous and robust nanocomposite of poly (3,4-ethylenedioxythiophene) (PEDOT) and carbon nanofiber (CNF) as a solid doping template for high-performance in vivo neuronal recording and stimulation. A simple yet well-controlled deposition strategy was developed via in situ electrochemical polymerization technique to create a porous network of PEDOT and CNFs on a flexible 4-channel gold microelectrode probe. Different morphological and electrochemical characterizations showed that they exhibit remarkable and superior electrochemical properties, yielding microelectrodes combining high surface area, low impedance (16.8 ± 2 MΩ µm2 at 1 kHz) and elevated charge injection capabilities (7.6 ± 1.3 mC/cm2) that exceed those of pure and composite PEDOT layers. In addition, the PEDOT-CNF composite electrode exhibited extended biphasic charge cycle endurance and excellent performance under accelerated lifetime testing, resulting in a negligible physical delamination and/or degradation for long periods of electrical stimulation. In vitro testing on mouse brain slices showed that they can record spontaneous oscillatory field potentials as well as single-unit action potentials and allow to safely deliver electrical stimulation for evoking field potentials. The combined superior electrical properties, durability and 3D microstructure topology of the PEDOT-CNF composite electrodes demonstrate outstanding potential for developing future neural surface interfacing applications.
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Affiliation(s)
| | - Valentin Saunier
- Laboratory for Analysis and Architecture of Systems (LAAS), CNRS, Toulouse, France
| | - Lionel G Nowak
- Centre de Recherche Cerveau et Cognition (CerCo), CNRS, Toulouse, France
| | | | - Christian Bergaud
- Laboratory for Analysis and Architecture of Systems (LAAS), CNRS, Toulouse, France
| | - Ali Maziz
- Laboratory for Analysis and Architecture of Systems (LAAS), CNRS, Toulouse, France
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17
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Nimbalkar S, Samejima S, Dang V, Hunt T, Nunez O, Moritz C, Kassegne S. Graphene on glassy carbon microelectrodes demonstrate long-term structural and functional stability in neurophysiological recording and stimulation. J Neural Eng 2021; 18. [PMID: 34492644 DOI: 10.1088/1741-2552/ac245a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 09/07/2021] [Indexed: 11/12/2022]
Abstract
Objective.There is a growing interest in the use of carbon and its allotropes for microelectrodes in neural probes because of their inertness, long-term electrical and electrochemical stability, and versatility. Building on this interest, we introduce a new electrode material system consisting of an ultra-thin monoatomic layer of graphene (Gr) mechanically supported by a relatively thicker layer of glassy carbon (GC).Approach.Due to its high electrical conductivity and high double-layer capacitance, Gr has impressive electrical and electrochemical properties, two key properties that are useful for neural recording and stimulation applications. However, because of its two-dimensional nature, Gr exhibits a lack of stiffness in the transverse direction and hence almost non-existent flexural and out-of-plane rigidity that will severely limit its wider use. On the other hand, GC is one of carbon's important allotropes and consists of three-dimensional microstructures of Gr fragments with a natural molecular similarity to Gr. Further, GC has exceptional chemical inertness, good electrical properties, high electrochemical stability, purely capacitive charge injection, and fast surface electrokinetics coupled with lithography patternability. This makes GC an ideal candidate for addressing Gr's lack of out-of-plane rigidity through providing a matching sturdier and robust mechanical backing. Combining the strengths of these two allotropes of carbon, we introduce a new neural probe that consists of ∼1 nm thick layer of patterned Gr microelectrodes supported by another layer of 3-5μm thick patterned GC.Main results. We present the fabrication technology for the newGr on GC(graphene on glassy carbon) microelectrodes and the accompanying pattern transfer technology on flexible substrate and report on the bond between these two allotropes of carbon through FTIR, surface morphology through SEM, topography through atomic force microscopy, and microstructure imaging through scanning transmission electron microscopy. A long-term (18 weeks)in vivostudy of the use of theseGr on GCmicroelectrodes assessed the quality of the electrocorticography-based neural signal recording and stimulation through electrophysiological measurements. The probes were demonstrated to be functionally and structurally stable over the 18 week period with minimal glial response-the longest reported so far for Gr-based microelectrodes.Significance.TheGr on GCmicroelectrodes presented here offers a compelling case for expanding the potentials of Gr-based technology in the broad areas of neural probes.
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Affiliation(s)
- Surabhi Nimbalkar
- NanoFAB.SDSU Research Lab, Department of Mechanical Engineering, College of Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, United States of America.,NSF-ERC Center for Neurotechnology (CNT), Seattle, WA 98195, United States of America
| | - Soshi Samejima
- Departments of Electrical & Computer Engineering, and Rehabilitation Medicine, University of Washington, Seattle, WA, United States of America.,NSF-ERC Center for Neurotechnology (CNT), Seattle, WA 98195, United States of America
| | - Viet Dang
- Departments of Electrical & Computer Engineering, and Rehabilitation Medicine, University of Washington, Seattle, WA, United States of America.,NSF-ERC Center for Neurotechnology (CNT), Seattle, WA 98195, United States of America
| | - Trevor Hunt
- NanoFAB.SDSU Research Lab, Department of Mechanical Engineering, College of Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, United States of America.,NSF-ERC Center for Neurotechnology (CNT), Seattle, WA 98195, United States of America
| | - Omar Nunez
- NanoFAB.SDSU Research Lab, Department of Mechanical Engineering, College of Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, United States of America.,NSF-ERC Center for Neurotechnology (CNT), Seattle, WA 98195, United States of America
| | - Chet Moritz
- Departments of Electrical & Computer Engineering, and Rehabilitation Medicine, University of Washington, Seattle, WA, United States of America.,Departments of Physiology Biophysics, University of Washington, Seattle, WA, United States of America.,NSF-ERC Center for Neurotechnology (CNT), Seattle, WA 98195, United States of America
| | - Sam Kassegne
- NanoFAB.SDSU Research Lab, Department of Mechanical Engineering, College of Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, United States of America.,NSF-ERC Center for Neurotechnology (CNT), Seattle, WA 98195, United States of America
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18
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Devi M, Vomero M, Fuhrer E, Castagnola E, Gueli C, Nimbalkar S, Hirabayashi M, Kassegne S, Stieglitz T, Sharma S. Carbon-based neural electrodes: promises and challenges. J Neural Eng 2021; 18. [PMID: 34404037 DOI: 10.1088/1741-2552/ac1e45] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 08/17/2021] [Indexed: 01/01/2023]
Abstract
Neural electrodes are primary functional elements of neuroelectronic devices designed to record neural activity based on electrochemical signals. These electrodes may also be utilized for electrically stimulating the neural cells, such that their response can be simultaneously recorded. In addition to being medically safe, the electrode material should be electrically conductive and electrochemically stable under harsh biological environments. Mechanical flexibility and conformability, resistance to crack formation and compatibility with common microfabrication techniques are equally desirable properties. Traditionally, (noble) metals have been the preferred for neural electrode applications due to their proven biosafety and a relatively high electrical conductivity. Carbon is a recent addition to this list, which is far superior in terms of its electrochemical stability and corrosion resistance. Carbon has also enabled 3D electrode fabrication as opposed to the thin-film based 2D structures. One of carbon's peculiar aspects is its availability in a wide range of allotropes with specialized properties that render it highly versatile. These variations, however, also make it difficult to understand carbon itself as a unique material, and thus, each allotrope is often regarded independently. Some carbon types have already shown promising results in bioelectronic medicine, while many others remain potential candidates. In this topical review, we first provide a broad overview of the neuroelectronic devices and the basic requirements of an electrode material. We subsequently discuss the carbon family of materials and their properties that are useful in neural applications. Examples of devices fabricated using bulk and nano carbon materials are reviewed and critically compared. We then summarize the challenges, future prospects and next-generation carbon technology that can be helpful in the field of neural sciences. The article aims at providing a common platform to neuroscientists, electrochemists, biologists, microsystems engineers and carbon scientists to enable active and comprehensive efforts directed towards carbon-based neuroelectronic device fabrication.
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Affiliation(s)
- Mamta Devi
- School of Engineering, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175075, India
| | - Maria Vomero
- Bioelectronic Systems Laboratory, Columbia University, 500 West 120th Street, New York, NY 10027, United States of America
| | - Erwin Fuhrer
- School of Computing and Electrical Engineering, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175075 India
| | - Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, United States of America
| | - Calogero Gueli
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Koehler-Allee 080, 79110 Freiburg, Germany
| | - Surabhi Nimbalkar
- NanoFAB.SDSU Research Lab, Department of Mechanical Engineering, San Diego State University and NSF-ERC Center for Neurotechnology (CNT), 5500 Campanile Drive, San Diego, CA 92182, United States of America
| | - Mieko Hirabayashi
- NanoFAB.SDSU Research Lab, Department of Mechanical Engineering, San Diego State University and NSF-ERC Center for Neurotechnology (CNT), 5500 Campanile Drive, San Diego, CA 92182, United States of America
| | - Sam Kassegne
- NanoFAB.SDSU Research Lab, Department of Mechanical Engineering, San Diego State University and NSF-ERC Center for Neurotechnology (CNT), 5500 Campanile Drive, San Diego, CA 92182, United States of America
| | - Thomas Stieglitz
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Koehler-Allee 080, 79110 Freiburg, Germany.,BrainLinks-BrainTools Center, University of Freiburg, Georges-Koehler-Allee 080, 79110 Freiburg, Germany.,Bernstein Center Freiburg, University of Freiburg, Hansastr. 9a, 79104 Freiburg, Germany
| | - Swati Sharma
- School of Engineering, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175075, India
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19
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Feng C, Frewin CL, Tanjil MRE, Everly R, Bieber J, Kumar A, Wang MC, Saddow SE. A Flexible a-SiC-Based Neural Interface Utilizing Pyrolyzed-Photoresist Film (C) Active Sites. MICROMACHINES 2021; 12:821. [PMID: 34357231 PMCID: PMC8304835 DOI: 10.3390/mi12070821] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/07/2021] [Accepted: 07/10/2021] [Indexed: 01/06/2023]
Abstract
Carbon containing materials, such as graphene, carbon-nanotubes (CNT), and graphene oxide, have gained prominence as possible electrodes in implantable neural interfaces due to their excellent conductive properties. While carbon is a promising electrochemical interface, many fabrication processes are difficult to perform, leading to issues with large scale device production and overall repeatability. Here we demonstrate that carbon electrodes and traces constructed from pyrolyzed-photoresist-film (PPF) when combined with amorphous silicon carbide (a-SiC) insulation could be fabricated with repeatable processes which use tools easily available in most semiconductor facilities. Directly forming PPF on a-SiC simplified the fabrication process which eliminates noble metal evaporation/sputtering and lift-off processes on small features. PPF electrodes in oxygenated phosphate buffered solution at pH 7.4 demonstrated excellent electrochemical charge storage capacity (CSC) of 14.16 C/cm2, an impedance of 24.8 ± 0.4 kΩ, and phase angle of -35.9 ± 0.6° at 1 kHz with a 1.9 kµm2 recording site area.
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Affiliation(s)
- Chenyin Feng
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA;
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | | | - Md Rubayat-E Tanjil
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | - Richard Everly
- Nanotechnology Research & Education Center, University of South Florida, Tampa, FL 33620, USA; (R.E.); (J.B.)
| | - Jay Bieber
- Nanotechnology Research & Education Center, University of South Florida, Tampa, FL 33620, USA; (R.E.); (J.B.)
| | - Ashok Kumar
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | - Michael Cai Wang
- Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620, USA; (M.R.-E.T.); (A.K.); (M.C.W.)
| | - Stephen E. Saddow
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA;
- Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA
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20
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Castagnola E, Garg R, Rastogi SK, Cohen-Karni T, Cui XT. 3D fuzzy graphene microelectrode array for dopamine sensing at sub-cellular spatial resolution. Biosens Bioelectron 2021; 191:113440. [PMID: 34171734 DOI: 10.1016/j.bios.2021.113440] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/28/2021] [Accepted: 06/13/2021] [Indexed: 02/07/2023]
Abstract
The development of a high sensitivity real-time sensor for multi-site detection of dopamine (DA) with high spatial and temporal resolution is of fundamental importance to study the complex spatial and temporal pattern of DA dynamics in the brain, thus improving the understanding and treatments of neurological and neuropsychiatric disorders. In response to this need, here we present high surface area out-of-plane grown three-dimensional (3D) fuzzy graphene (3DFG) microelectrode arrays (MEAs) for highly selective, sensitive, and stable DA electrochemical sensing. 3DFG microelectrodes present a remarkable sensitivity to DA (2.12 ± 0.05 nA/nM, with LOD of 364.44 ± 8.65 pM), the highest reported for nanocarbon MEAs using Fast Scan Cyclic Voltammetry (FSCV). The high surface area of 3DFG allows for miniaturization of electrode down to 2 × 2 μm2, without compromising the electrochemical performance. Moreover, 3DFG MEAs are electrochemically stable under 7.2 million scans of continuous FSCV cycling, present exceptional selectivity over the most common interferents in vitro with minimum fouling by electrochemical byproducts and can discriminate DA and serotonin (5-HT) in response to the injection of their 50:50 mixture. These results highlight the potential of 3DFG MEAs as a promising platform for FSCV based multi-site detection of DA with high sensitivity, selectivity, and spatial resolution.
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Affiliation(s)
- Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, PA 15260 Pittsburgh, PA, USA
| | - Raghav Garg
- Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA
| | - Sahil K Rastogi
- Department of Biomedical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA
| | - Tzahi Cohen-Karni
- Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA; Department of Biomedical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive Pittsburgh, PA, 15219-3110, USA.
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, PA 15260 Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive Pittsburgh, PA, 15219-3110, USA; Center for Neural Basis of Cognition, University of Pittsburgh, 4400 Fifth Ave, Pittsburgh, PA 15213, Pittsburgh, PA, 15261, USA.
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21
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Zheng XS, Tan C, Castagnola E, Cui XT. Electrode Materials for Chronic Electrical Microstimulation. Adv Healthc Mater 2021; 10:e2100119. [PMID: 34029008 PMCID: PMC8257249 DOI: 10.1002/adhm.202100119] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/20/2021] [Indexed: 02/06/2023]
Abstract
Electrical microstimulation has enabled partial restoration of vision, hearing, movement, somatosensation, as well as improving organ functions by electrically modulating neural activities. However, chronic microstimulation is faced with numerous challenges. The implantation of an electrode array into the neural tissue triggers an inflammatory response, which can be exacerbated by the delivery of electrical currents. Meanwhile, prolonged stimulation may lead to electrode material degradation., which can be accelerated by the hostile inflammatory environment. Both material degradation and adverse tissue reactions can compromise stimulation performance over time. For stable chronic electrical stimulation, an ideal microelectrode must present 1) high charge injection limit, to efficiently deliver charge without exceeding safety limits for both tissue and electrodes, 2) small size, to gain high spatial selectivity, 3) excellent biocompatibility that ensures tissue health immediately next to the device, and 4) stable in vivo electrochemical properties over the application period. In this review, the challenges in chronic microstimulation are described in detail. To aid material scientists interested in neural stimulation research, the in vitro and in vivo testing methods are introduced for assessing stimulation functionality and longevity and a detailed overview of recent advances in electrode material research and device fabrication for improving chronic microstimulation performance is provided.
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Affiliation(s)
- Xin Sally Zheng
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Chao Tan
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
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22
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Brain neurochemical monitoring. Biosens Bioelectron 2021; 189:113351. [PMID: 34049083 DOI: 10.1016/j.bios.2021.113351] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 05/05/2021] [Accepted: 05/13/2021] [Indexed: 02/08/2023]
Abstract
Brain neurochemical monitoring aims to provide continuous and accurate measurements of brain biomarkers. It has enabled significant advances in neuroscience for application in clinical diagnostics, treatment, and prevention of brain diseases. Microfabricated electrochemical and optical spectroscopy sensing technologies have been developed for precise monitoring of brain neurochemicals. Here, a comprehensive review on the progress of sensing technologies developed for brain neurochemical monitoring is presented. The review provides a summary of the widely measured clinically relevant neurochemicals and commonly adopted recognition technologies. Recent advances in sampling, electrochemistry, and optical spectroscopy for brain neurochemical monitoring are highlighted and their application are discussed. Existing gaps in current technologies and future directions to design industry standard brain neurochemical sensing devices for clinical applications are addressed.
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23
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Forouzanfar S, Pala N, Madou M, Wang C. Perspectives on C-MEMS and C-NEMS biotech applications. Biosens Bioelectron 2021; 180:113119. [PMID: 33711652 DOI: 10.1016/j.bios.2021.113119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 02/19/2021] [Accepted: 02/25/2021] [Indexed: 02/04/2023]
Abstract
Carbon microelectromechanical system (C-MEMS) and carbon nanoelectromechanical system (C-NEMS) have been identified as promising technologies for a range of biotech applications, including electrochemical biosensors, biofuel cells, neural probes, and dielectrophoretic cell trapping. Research teams around the world have devoted more and more time to this field. After almost two decades of efforts on developing C-MEMS and C-NEMS, a review of the relevant progress and addressing future research opportunities and critical issues is in order. This review first introduces C-MEMS and C-NEMS fabrication processes that fall into two categories: photolithography- and non-photolithography- based techniques. Next, a detailed discussion of the state of the art, and technical challenges and opportunities associated with C-MEMS and C-NEMS devices used in biotech applications are presented. These devices are discussed in the relevant sub-sections of biosensors, biofuel cells, intracorporeal neural probe, dielectrophoresis cell trapping, and cell culture. The review concludes with an exposition of future perspectives in C-MEMS and C-NEMS.
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Affiliation(s)
- Shahrzad Forouzanfar
- Electrical and Computer Engineering, Florida International University, United States
| | - Nezih Pala
- Electrical and Computer Engineering, Florida International University, United States
| | - Marc Madou
- Mechanical and Aerospace Engineering, University of California Irvine, United States
| | - Chunlei Wang
- Mechanical and Materials Engineering, Florida International University, United States; Center for Study of Matter at Extreme Conditions, Florida International University, United States.
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24
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McGlynn E, Nabaei V, Ren E, Galeote‐Checa G, Das R, Curia G, Heidari H. The Future of Neuroscience: Flexible and Wireless Implantable Neural Electronics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002693. [PMID: 34026431 PMCID: PMC8132070 DOI: 10.1002/advs.202002693] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/15/2021] [Indexed: 05/04/2023]
Abstract
Neurological diseases are a prevalent cause of global mortality and are of growing concern when considering an ageing global population. Traditional treatments are accompanied by serious side effects including repeated treatment sessions, invasive surgeries, or infections. For example, in the case of deep brain stimulation, large, stiff, and battery powered neural probes recruit thousands of neurons with each pulse, and can invoke a vigorous immune response. This paper presents challenges in engineering and neuroscience in developing miniaturized and biointegrated alternatives, in the form of microelectrode probes. Progress in design and topology of neural implants has shifted the goal post toward highly specific recording and stimulation, targeting small groups of neurons and reducing the foreign body response with biomimetic design principles. Implantable device design recommendations, fabrication techniques, and clinical evaluation of the impact flexible, integrated probes will have on the treatment of neurological disorders are provided in this report. The choice of biocompatible material dictates fabrication techniques as novel methods reduce the complexity of manufacture. Wireless power, the final hurdle to truly implantable neural interfaces, is discussed. These aspects are the driving force behind continued research: significant breakthroughs in any one of these areas will revolutionize the treatment of neurological disorders.
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Affiliation(s)
- Eve McGlynn
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Vahid Nabaei
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Elisa Ren
- Laboratory of Experimental Electroencephalography and NeurophysiologyDepartment of BiomedicalMetabolic and Neural SciencesUniversity of Modena and Reggio EmiliaModena41125Italy
| | - Gabriel Galeote‐Checa
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Rupam Das
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Giulia Curia
- Laboratory of Experimental Electroencephalography and NeurophysiologyDepartment of BiomedicalMetabolic and Neural SciencesUniversity of Modena and Reggio EmiliaModena41125Italy
| | - Hadi Heidari
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
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25
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Hejazi M, Tong W, Ibbotson MR, Prawer S, Garrett DJ. Advances in Carbon-Based Microfiber Electrodes for Neural Interfacing. Front Neurosci 2021; 15:658703. [PMID: 33912007 PMCID: PMC8072048 DOI: 10.3389/fnins.2021.658703] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
Neural interfacing devices using penetrating microelectrode arrays have emerged as an important tool in both neuroscience research and medical applications. These implantable microelectrode arrays enable communication between man-made devices and the nervous system by detecting and/or evoking neuronal activities. Recent years have seen rapid development of electrodes fabricated using flexible, ultrathin carbon-based microfibers. Compared to electrodes fabricated using rigid materials and larger cross-sections, these microfiber electrodes have been shown to reduce foreign body responses after implantation, with improved signal-to-noise ratio for neural recording and enhanced resolution for neural stimulation. Here, we review recent progress of carbon-based microfiber electrodes in terms of material composition and fabrication technology. The remaining challenges and future directions for development of these arrays will also be discussed. Overall, these microfiber electrodes are expected to improve the longevity and reliability of neural interfacing devices.
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Affiliation(s)
- Maryam Hejazi
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
| | - Wei Tong
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC, Australia
| | - Michael R. Ibbotson
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC, Australia
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Steven Prawer
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
| | - David J. Garrett
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
- School of Engineering, RMIT University, Melbourne, VIC, Australia
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26
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Jiang S, Song J, Zhang Y, Nie M, Kim J, Marcano AL, Kadlec K, Mills WA, Yan X, Liu H, Tong R, Wang H, Kimbrough IF, Sontheimer H, Zhou W, Jia X. Nano-optoelectrodes Integrated with Flexible Multifunctional Fiber Probes by High-Throughput Scalable Fabrication. ACS APPLIED MATERIALS & INTERFACES 2021; 13:9156-9165. [PMID: 33566572 PMCID: PMC10564641 DOI: 10.1021/acsami.0c19187] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Metallic nano-optoelectrode arrays can simultaneously serve as nanoelectrodes to increase the electrochemical surface-to-volume ratio for high-performance electrical recording and optical nanoantennas to achieve nanoscale light concentrations for ultrasensitive optical sensing. However, it remains a challenge to integrate nano-optoelectrodes with a miniaturized multifunctional probing system for combined electrical recording and optical biosensing in vivo. Here, we report that flexible nano-optoelectrode-integrated multifunctional fiber probes can have hybrid optical-electrical sensing multimodalities, including optical refractive index sensing, surface-enhanced Raman spectroscopy, and electrophysiological recording. By physical vapor deposition of thin metal films through free-standing masks of nanohole arrays, we exploit a scalable nanofabrication process to create nano-optoelectrode arrays on the tips of flexible multifunctional fiber probes. We envision that the development of flexible nano-optoelectrode-integrated multifunctional fiber probes can open significant opportunities by allowing for multimodal monitoring of brain activities with combined capabilities for simultaneous electrical neural recording and optical biochemical sensing at the single-cell level.
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Affiliation(s)
- Shan Jiang
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24060, USA
| | - Junyeob Song
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24060, USA
| | - Yujing Zhang
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24060, USA
| | - Meitong Nie
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24060, USA
| | - Jongwoon Kim
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24060, USA
| | - Ana Lopez Marcano
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24060, USA
| | - Kelly Kadlec
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24060, USA
| | - William A. Mills
- Translational Biology, Medicine, and Health, Virginia Tech, Roanoke, VA 24061, USA
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
| | - Xiaodong Yan
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Hefei Liu
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Rong Tong
- Department of Chemical Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - Han Wang
- Fralin Biomedical Research Institute, Roanoke, VA 24061, USA
| | - Ian F. Kimbrough
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
| | - Harald Sontheimer
- Translational Biology, Medicine, and Health, Virginia Tech, Roanoke, VA 24061, USA
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Biomedical Research Institute, Roanoke, VA 24061, USA
| | - Wei Zhou
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24060, USA
| | - Xiaoting Jia
- Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24060, USA
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27
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Purcell EK, Becker MF, Guo Y, Hara SA, Ludwig KA, McKinney CJ, Monroe EM, Rechenberg R, Rusinek CA, Saxena A, Siegenthaler JR, Sortwell CE, Thompson CH, Trevathan JK, Witt S, Li W. Next-Generation Diamond Electrodes for Neurochemical Sensing: Challenges and Opportunities. MICROMACHINES 2021; 12:128. [PMID: 33530395 PMCID: PMC7911340 DOI: 10.3390/mi12020128] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/19/2021] [Accepted: 01/19/2021] [Indexed: 12/12/2022]
Abstract
Carbon-based electrodes combined with fast-scan cyclic voltammetry (FSCV) enable neurochemical sensing with high spatiotemporal resolution and sensitivity. While their attractive electrochemical and conductive properties have established a long history of use in the detection of neurotransmitters both in vitro and in vivo, carbon fiber microelectrodes (CFMEs) also have limitations in their fabrication, flexibility, and chronic stability. Diamond is a form of carbon with a more rigid bonding structure (sp3-hybridized) which can become conductive when boron-doped. Boron-doped diamond (BDD) is characterized by an extremely wide potential window, low background current, and good biocompatibility. Additionally, methods for processing and patterning diamond allow for high-throughput batch fabrication and customization of electrode arrays with unique architectures. While tradeoffs in sensitivity can undermine the advantages of BDD as a neurochemical sensor, there are numerous untapped opportunities to further improve performance, including anodic pretreatment, or optimization of the FSCV waveform, instrumentation, sp2/sp3 character, doping, surface characteristics, and signal processing. Here, we review the state-of-the-art in diamond electrodes for neurochemical sensing and discuss potential opportunities for future advancements of the technology. We highlight our team's progress with the development of an all-diamond fiber ultramicroelectrode as a novel approach to advance the performance and applications of diamond-based neurochemical sensors.
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Affiliation(s)
- Erin K. Purcell
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA; (Y.G.); (A.S.); (W.L.)
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, USA;
- Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA;
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Michael F. Becker
- Fraunhofer USA Center Midwest, East Lansing, MI 48824, USA; (M.F.B.); (R.R.); (J.R.S.); (S.W.)
| | - Yue Guo
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA; (Y.G.); (A.S.); (W.L.)
| | - Seth A. Hara
- Division of Engineering, Mayo Clinic, Rochester, MN 55905, USA;
| | - Kip A. Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; (K.A.L.); (J.K.T.)
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Collin J. McKinney
- Department of Chemistry, Electronics Core Facility, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA;
| | - Elizabeth M. Monroe
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154, USA; (E.M.M.); (C.A.R.)
| | - Robert Rechenberg
- Fraunhofer USA Center Midwest, East Lansing, MI 48824, USA; (M.F.B.); (R.R.); (J.R.S.); (S.W.)
| | - Cory A. Rusinek
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154, USA; (E.M.M.); (C.A.R.)
| | - Akash Saxena
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA; (Y.G.); (A.S.); (W.L.)
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - James R. Siegenthaler
- Fraunhofer USA Center Midwest, East Lansing, MI 48824, USA; (M.F.B.); (R.R.); (J.R.S.); (S.W.)
| | - Caryl E. Sortwell
- Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA;
- Department of Translational Neuroscience, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - Cort H. Thompson
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, USA;
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - James K. Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; (K.A.L.); (J.K.T.)
- Grainger Institute for Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Suzanne Witt
- Fraunhofer USA Center Midwest, East Lansing, MI 48824, USA; (M.F.B.); (R.R.); (J.R.S.); (S.W.)
| | - Wen Li
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA; (Y.G.); (A.S.); (W.L.)
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, USA;
- Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA;
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
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28
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Castagnola E, Robbins EM, Woeppel KM, McGuier M, Golabchi A, Taylor IM, Michael AC, Cui XT. Real-Time Fast Scan Cyclic Voltammetry Detection and Quantification of Exogenously Administered Melatonin in Mice Brain. Front Bioeng Biotechnol 2020; 8:602216. [PMID: 33330433 PMCID: PMC7732424 DOI: 10.3389/fbioe.2020.602216] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/30/2020] [Indexed: 01/19/2023] Open
Abstract
Melatonin (MT) has been recently considered an excellent candidate for the treatment of sleep disorders, neural injuries, and neurological diseases. To better investigate the actions of MT in various brain functions, real-time detection of MT concentrations in specific brain regions is much desired. Previously, we have demonstrated detection of exogenously administered MT in anesthetized mouse brain using square wave voltammetry (SWV). Here, for the first time, we show successful detection of exogenous MT in the brain using fast scan cyclic voltammetry (FSCV) on electrochemically pre-activated carbon fiber microelectrodes (CFEs). In vitro evaluation showed the highest sensitivity (28.1 nA/μM) and lowest detection limit (20.2 ± 4.8 nM) ever reported for MT detection at carbon surface. Additionally, an extensive CFE stability and fouling assessment demonstrated that a prolonged CFE pre-conditioning stabilizes the background, in vitro and in vivo, and provides consistent CFE sensitivity over time even in the presence of a high MT concentration. Finally, the stable in vivo background, with minimized CFE fouling, allows us to achieve a drift-free FSCV detection of exogenous administered MT in mouse brain over a period of 3 min, which is significantly longer than the duration limit (usually < 90 s) for traditional in vivo FSCV acquisition. The MT concentration and dynamics measured by FSCV are in good agreement with SWV, while microdialysis further validated the concentration range. These results demonstrated reliable MT detection using FSCV that has the potential to monitor MT in the brain over long periods of time.
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Affiliation(s)
- Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Elaine M. Robbins
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kevin M. Woeppel
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States
| | - Moriah McGuier
- Department of Chemistry, Saint Vincent College, Latrobe, PA, United States
| | - Asiyeh Golabchi
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States
| | - I. Mitch Taylor
- Department of Chemistry, Saint Vincent College, Latrobe, PA, United States
| | - Adrian C. Michael
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
- Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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29
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Boehler C, Carli S, Fadiga L, Stieglitz T, Asplund M. Tutorial: guidelines for standardized performance tests for electrodes intended for neural interfaces and bioelectronics. Nat Protoc 2020; 15:3557-3578. [DOI: 10.1038/s41596-020-0389-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/28/2020] [Indexed: 01/22/2023]
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Vahidi NW, Rudraraju S, Castagnola E, Cea C, Nimbalkar S, Hanna R, Arvizu R, Dayeh SA, Gentner TQ, Kassegne S. Epi-Intra neural probes with glassy carbon microelectrodes help elucidate neural coding and stimulus encoding in 3D volume of tissue. J Neural Eng 2020; 17:046005. [PMID: 32521531 DOI: 10.1088/1741-2552/ab9b5c] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE In this study, we demonstrate practical applications of a novel 3-dimensional neural probe for simultaneous electrophysiological recordings from the surface of the brain as well as deep intra-cortical tissue. We used this 3D probe to investigate signal propagation mechanisms between neuronal cells and their responses to stimuli in a 3D fashion. APPROACH This novel probe leverage 2D thin-film microfabrication technique to combine an epi-cortical (surface) and an intra-cortical (depth) microelectrode arrays (Epi-Intra), that unfold into an origami 3D-like probe during brain implantation. The flexible epi-cortical component conforms to the brain surface while the intra-cortical array is reinforced with stiffer durimide polymer layer for ease of tissue penetration. The microelectrodes are made of glassy carbon material that is biocompatible and has low electrochemical impedance that is important for high fidelity neuronal recordings. These recordings were performed on the auditory region of anesthetized European starling songbirds during playback of conspecific songs as auditory stimuli. MAIN RESULTS The Epi-Intra probe recorded broadband activity including local field potentials (LFPs) signals as well as single-unit activity and multi-unit activity from both surface and deep brain. The majority of recorded cellular activities were stimulus-locked and exhibited low noise. Notably, while LFPs recorded on surface and depth electrodes did not exhibit strong correlation, composite receptive fields (CRFs)-extracted from individual neuron cells through a non-linear model and that are cell-dependent-were correlated. SIGNIFICANCE These findings demonstrate that CRFs extracted from Epi-Intra recordings are excellent candidates for neural coding and for understanding the relationship between sensory neuronal responses and their stimuli (stimulus encoding). Beyond CRFs, this novel neural probe may enable new spatiotemporal 3D volumetric mapping to address, with cellular resolution, how the brain coordinates function.
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Affiliation(s)
- Nasim W Vahidi
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92093, United States of America
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31
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Gueli C, Vomero M, Sharma S, Stieglitz T. Integration of Micro-Patterned Carbon Fiber Mats into Polyimide for the Development of Flexible Implantable Neural Devices. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:3931-3934. [PMID: 31946732 DOI: 10.1109/embc.2019.8856960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Polymer-derived carbon as neural electrode material has recently been subject of interest due to its ability to act as a multimodal platform for simultaneous recording and stimulation of neural activity and neurotransmitter detection. Its mechanical properties and the inverse fabrication protocol commonly used for the manufacturing of pyrolyzed carbon thin-film devices, however, only allow for its use as the electrode material and not as material for interconnects and other conductive components. In this study -for the first time-a process to fabricate flexible neural devices entirely made of carbon fibers (CFs) and polyimide (PI) was developed. The devices consist of carbonized polyacrylonitrile (PAN) fiber mats embedded in polyimide, which were patterned into the desired shapes using reactive ion etching (RIE). This method allowed for the fabrication of miniaturized, flexible and conductive carbon components with critical dimensions of 12.5 μm. Tensile tests were performed to evaluate the mechanical stability of the CF/PI composite, to detect potential electrical resistance changes due to bending and to study the adhesion of different PI layers onto each other. A strong mechanical interlock between CFs and PI was demonstrated and no significant change in the resistance of the CFs was detected after 100k cycles of tensile bending (r = 3 mm). The fabrication approach proposed here successfully yielded entirely metal-free and entirely flexible electrodes. It opens the door to further studies with the guarantee of highly stable electrodes, both mechanically and electrically.
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Fan B, Rusinek CA, Thompson CH, Setien M, Guo Y, Rechenberg R, Gong Y, Weber AJ, Becker MF, Purcell E, Li W. Flexible, diamond-based microelectrodes fabricated using the diamond growth side for neural sensing. MICROSYSTEMS & NANOENGINEERING 2020; 6:42. [PMID: 32685185 PMCID: PMC7355183 DOI: 10.1038/s41378-020-0155-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/06/2020] [Accepted: 03/25/2020] [Indexed: 05/02/2023]
Abstract
Diamond possesses many favorable properties for biochemical sensors, including biocompatibility, chemical inertness, resistance to biofouling, an extremely wide potential window, and low double-layer capacitance. The hardness of diamond, however, has hindered its applications in neural implants due to the mechanical property mismatch between diamond and soft nervous tissues. Here, we present a flexible, diamond-based microelectrode probe consisting of multichannel boron-doped polycrystalline diamond (BDD) microelectrodes on a soft Parylene C substrate. We developed and optimized a wafer-scale fabrication approach that allows the use of the growth side of the BDD thin film as the sensing surface. Compared to the nucleation surface, the BDD growth side exhibited a rougher morphology, a higher sp 3 content, a wider water potential window, and a lower background current. The dopamine (DA) sensing capability of the BDD growth surface electrodes was validated in a 1.0 mM DA solution, which shows better sensitivity and stability than the BDD nucleation surface electrodes. The results of these comparative studies suggest that using the BDD growth surface for making implantable microelectrodes has significant advantages in terms of the sensitivity, selectivity, and stability of a neural implant. Furthermore, we validated the functionality of the BDD growth side electrodes for neural recordings both in vitro and in vivo. The biocompatibility of the microcrystalline diamond film was also assessed in vitro using rat cortical neuron cultures.
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Affiliation(s)
- Bin Fan
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI USA
| | - Cory A. Rusinek
- Fraunhofer USA Center for Coatings and Diamond Technologies, East Lansing, MI USA
| | - Cort H. Thompson
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI USA
| | - Monica Setien
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI USA
| | - Yue Guo
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI USA
| | - Robert Rechenberg
- Fraunhofer USA Center for Coatings and Diamond Technologies, East Lansing, MI USA
| | - Yan Gong
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI USA
| | - Arthur J. Weber
- Department of Physiology, Michigan State University, East Lansing, MI USA
| | - Michael F. Becker
- Fraunhofer USA Center for Coatings and Diamond Technologies, East Lansing, MI USA
| | - Erin Purcell
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI USA
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI USA
| | - Wen Li
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI USA
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Dalrymple AN, Huynh M, Robles UA, Marroquin JB, Lee CD, Petrossians A, Whalen JJ, Li D, Parkington HC, Forsythe JS, Green RA, Poole-Warren LA, Shepherd RK, Fallon JB. Electrochemical and mechanical performance of reduced graphene oxide, conductive hydrogel, and electrodeposited Pt-Ir coated electrodes: an active in vitro study. J Neural Eng 2019; 17:016015. [PMID: 31652427 DOI: 10.1088/1741-2552/ab5163] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE To systematically compare the in vitro electrochemical and mechanical properties of several electrode coatings that have been reported to increase the efficacy of medical bionics devices by increasing the amount of charge that can be delivered safely to the target neural tissue. APPROACH Smooth platinum (Pt) ring and disc electrodes were coated with reduced graphene oxide, conductive hydrogel, or electrodeposited Pt-Ir. Electrodes with coatings were compared with uncoated smooth Pt electrodes before and after an in vitro accelerated aging protocol. The various coatings were compared mechanically using the adhesion-by-tape test. Electrodes were stimulated in saline for 24 hours/day 7 days/week for 21 d at 85 °C (1.6-year equivalence) at a constant charge density of 200 µC/cm2/phase. Electrodes were graded on surface corrosion and trace analysis of Pt in the electrolyte after aging. Electrochemical measurements performed before, during, and after aging included electrochemical impedance spectroscopy, cyclic voltammetry, and charge injection limit and impedance from voltage transient recordings. MAIN RESULTS All three coatings adhered well to smooth Pt and exhibited electrochemical advantage over smooth Pt electrodes prior to aging. After aging, graphene coated electrodes displayed a stimulation-induced increase in impedance and reduction in the charge injection limit (p < 0.001), alongside extensive corrosion and release of Pt into the electrolyte. In contrast, both conductive hydrogel and Pt-Ir coated electrodes had smaller impedances and larger charge injection limits than smooth Pt electrodes (p < 0.001) following aging regardless of the stimulus level and with little evidence of corrosion or Pt dissolution. SIGNIFICANCE This study rigorously tested the mechanical and electrochemical performance of electrode coatings in vitro and provided suitable candidates for future in vivo testing.
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Ou Y, Buchanan AM, Witt CE, Hashemi P. Frontiers in Electrochemical Sensors for Neurotransmitter Detection: Towards Measuring Neurotransmitters as Chemical Diagnostics for Brain Disorders. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2019; 11:2738-2755. [PMID: 32724337 PMCID: PMC7386554 DOI: 10.1039/c9ay00055k] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
It is extremely challenging to chemically diagnose disorders of the brain. There is hence great interest in designing and optimizing tools for direct detection of chemical biomarkers implicated in neurological disorders to improve diagnosis and treatment. Tools that are capable of monitoring brain chemicals, neurotransmitters in particular, need to be biocompatible, perform with high spatiotemporal resolution, and ensure high selectivity and sensitivity. Recent advances in electrochemical methods are addressing these criteria; the resulting devices demonstrate great promise for in vivo neurotransmitter detection. None of these devices are currently used for diagnostic purposes, however these cutting-edge technologies are promising more sensitive, selective, faster, and less invasive measurements. Via this review we highlight significant technical advances and in vivo studies, performed in the last 5 years, that we believe will facilitate the development of diagnostic tools for brain disorders.
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Affiliation(s)
- Yangguang Ou
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia SC
| | - Anna Marie Buchanan
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia SC
| | - Colby E. Witt
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia SC
| | - Parastoo Hashemi
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia SC
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Nimbalkar S, Fuhrer E, Silva P, Nguyen T, Sereno M, Kassegne S, Korvink J. Glassy carbon microelectrodes minimize induced voltages, mechanical vibrations, and artifacts in magnetic resonance imaging. MICROSYSTEMS & NANOENGINEERING 2019; 5:61. [PMID: 31754453 PMCID: PMC6859162 DOI: 10.1038/s41378-019-0106-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/28/2019] [Accepted: 08/27/2019] [Indexed: 05/07/2023]
Abstract
The recent introduction of glassy carbon (GC) microstructures supported on flexible polymeric substrates has motivated the adoption of GC in a variety of implantable and wearable devices. Neural probes such as electrocorticography and penetrating shanks with GC microelectrode arrays used for neural signal recording and electrical stimulation are among the first beneficiaries of this technology. With the expected proliferation of these neural probes and potential clinical adoption, the magnetic resonance imaging (MRI) compatibility of GC microstructures needs to be established to help validate this potential in clinical settings. Here, we present GC microelectrodes and microstructures-fabricated through the carbon micro-electro-mechanical systems process and supported on flexible polymeric substrates-and carry out experimental measurements of induced vibrations, eddy currents, and artifacts. Through induced vibration, induced voltage, and MRI experiments and finite element modeling, we compared the performances of these GC microelectrodes against those of conventional thin-film platinum (Pt) microelectrodes and established that GC microelectrodes demonstrate superior magnetic resonance compatibility over standard metal thin-film microelectrodes. Specifically, we demonstrated that GC microelectrodes experienced no considerable vibration deflection amplitudes and minimal induced currents, while Pt microelectrodes had significantly larger currents. We also showed that because of their low magnetic susceptibility and lower conductivity, the GC microelectrodes caused almost no susceptibility shift artifacts and no eddy-current-induced artifacts compared to Pt microelectrodes. Taken together, the experimental, theoretical, and finite element modeling establish that GC microelectrodes exhibit significant MRI compatibility, hence demonstrating clear clinical advantages over current conventional thin-film materials, further opening avenues for wider adoption of GC microelectrodes in chronic clinical applications.
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Affiliation(s)
- Surabhi Nimbalkar
- MEMS Research Lab, Department of Mechanical Engineering,College of Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 USA
- NSF-ERC Center for Neurotechnology (CNT), Seattle, WA USA
| | - Erwin Fuhrer
- Institute of Microstructure Technology – Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz, 76344 Eggenstein-Leopoldshafen, Germany
| | - Pedro Silva
- Institute of Microstructure Technology – Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz, 76344 Eggenstein-Leopoldshafen, Germany
| | - Tri Nguyen
- MEMS Research Lab, Department of Mechanical Engineering,College of Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 USA
- NSF-ERC Center for Neurotechnology (CNT), Seattle, WA USA
| | - Martin Sereno
- Magnetic Resonance Imaging Lab, San Diego State University, San Diego, CA 92182 USA
| | - Sam Kassegne
- MEMS Research Lab, Department of Mechanical Engineering,College of Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 USA
- NSF-ERC Center for Neurotechnology (CNT), Seattle, WA USA
| | - Jan Korvink
- Institute of Microstructure Technology – Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz, 76344 Eggenstein-Leopoldshafen, Germany
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36
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Vomero M, Zucchini E, Delfino E, Gueli C, Mondragon NC, Carli S, Fadiga L, Stieglitz T. Glassy Carbon Electrocorticography Electrodes on Ultra-Thin and Finger-Like Polyimide Substrate: Performance Evaluation Based on Different Electrode Diameters. MATERIALS 2018; 11:ma11122486. [PMID: 30544545 PMCID: PMC6316905 DOI: 10.3390/ma11122486] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/03/2018] [Accepted: 12/05/2018] [Indexed: 02/07/2023]
Abstract
Glassy carbon (GC) has high potential to serve as a biomaterial in neural applications because it is biocompatible, electrochemically inert and can be incorporated in polyimide-based implantable devices. Miniaturization and applicability of GC is, however, thought to be partially limited by its electrical conductivity. For this study, ultra-conformable polyimide-based electrocorticography (ECoG) devices with different-diameter GC electrodes were fabricated and tested in vitro and in rat models. For achieving conformability to the rat brain, polyimide was patterned in a finger-like shape and its thickness was set to 8 µm. To investigate different electrode sizes, each ECoG device was assigned electrodes with diameters of 50, 100, 200 and 300 µm. They were electrochemically characterized and subjected to 10 million biphasic pulses—for achieving a steady-state—and to X-ray photoelectron spectroscopy, for examining their elemental composition. The electrodes were then implanted epidurally to evaluate the ability of each diameter to detect neural activity. Results show that their performance at low frequencies (up to 300 Hz) depends on the distance from the signal source rather than on the electrode diameter, while at high frequencies (above 200 Hz) small electrodes have higher background noises than large ones, unless they are coated with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS).
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Affiliation(s)
- Maria Vomero
- Institute of Microsystem Technology (IMTEK), Laboratory for Biomedical Microtechnology, Georges-Koehler-Allee 102, D-79110 Freiburg, Germany.
- Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Georges-Koehler-Allee 80, 79110 Freiburg, Germany.
| | - Elena Zucchini
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di Tecnologia (IIT), Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
- Section of Human Physiology University of Ferrara, Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
| | - Emanuela Delfino
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di Tecnologia (IIT), Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
- Section of Human Physiology University of Ferrara, Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
| | - Calogero Gueli
- Institute of Microsystem Technology (IMTEK), Laboratory for Biomedical Microtechnology, Georges-Koehler-Allee 102, D-79110 Freiburg, Germany.
| | - Norma Carolina Mondragon
- Institute of Microsystem Technology (IMTEK), Laboratory for Biomedical Microtechnology, Georges-Koehler-Allee 102, D-79110 Freiburg, Germany.
| | - Stefano Carli
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di Tecnologia (IIT), Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
| | - Luciano Fadiga
- Center for Translational Neurophysiology of Speech and Communication, Istituto Italiano di Tecnologia (IIT), Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
- Section of Human Physiology University of Ferrara, Via Fossato di Mortara 17/19, 44121 Ferrara, Italy.
| | - Thomas Stieglitz
- Institute of Microsystem Technology (IMTEK), Laboratory for Biomedical Microtechnology, Georges-Koehler-Allee 102, D-79110 Freiburg, Germany.
- Cluster of Excellence BrainLinks-BrainTools, University of Freiburg, Georges-Koehler-Allee 80, 79110 Freiburg, Germany.
- Bernstein Center Freiburg, University of Freiburg, Hansastrasse 9a, 79104 Freiburg, Germany.
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