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Sirolli S, Guarnera D, Ricotti L, Cafarelli A. Triggerable Patches for Medical Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2310110. [PMID: 38860756 DOI: 10.1002/adma.202310110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 06/05/2024] [Indexed: 06/12/2024]
Abstract
Medical patches have garnered increasing attention in recent decades for several diagnostic and therapeutic applications. Advancements in material science, manufacturing technologies, and bioengineering have significantly widened their functionalities, rendering them highly versatile platforms for wearable and implantable applications. Of particular interest are triggerable patches designed for drug delivery and tissue regeneration purposes, whose action can be controlled by an external signal. Stimuli-responsive patches are particularly appealing as they may enable a high level of temporal and spatial control over the therapy, allowing high therapeutic precision and the possibility to adjust the treatment according to specific clinical and personal needs. This review aims to provide a comprehensive overview of the existing extensive literature on triggerable patches, emphasizing their potential for diverse applications and highlighting the strengths and weaknesses of different triggering stimuli. Additionally, the current open challenges related to the design and use of efficient triggerable patches, such as tuning their mechanical and adhesive properties, ensuring an acceptable trade-off between smartness and biocompatibility, endowing them with portability and autonomy, accurately controlling their responsiveness to the triggering stimulus and maximizing their therapeutic efficacy, are reviewed.
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Affiliation(s)
- Sofia Sirolli
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, Pisa, 56127, Italy
- Department of Excellence in Robotics & AI, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, Pisa, 56127, Italy
| | - Daniele Guarnera
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, Pisa, 56127, Italy
- Department of Excellence in Robotics & AI, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, Pisa, 56127, Italy
| | - Leonardo Ricotti
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, Pisa, 56127, Italy
- Department of Excellence in Robotics & AI, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, Pisa, 56127, Italy
| | - Andrea Cafarelli
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, Pisa, 56127, Italy
- Department of Excellence in Robotics & AI, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, Pisa, 56127, Italy
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2
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Yan D, Ruiz JRL, Hsieh ML, Jeong D, Vöröslakos M, Lanzio V, Warner EV, Ko E, Tian Y, Patel PR, ElBidweihy H, Smith CS, Lee JH, Cheon J, Buzsáki G, Yoon E. Self-Assembled Origami Neural Probes for Scalable, Multifunctional, Three-Dimensional Neural Interface. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.591141. [PMID: 38712092 PMCID: PMC11071508 DOI: 10.1101/2024.04.25.591141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Flexible intracortical neural probes have drawn attention for their enhanced longevity in high-resolution neural recordings due to reduced tissue reaction. However, the conventional monolithic fabrication approach has met significant challenges in: (i) scaling the number of recording sites for electrophysiology; (ii) integrating of other physiological sensing and modulation; and (iii) configuring into three-dimensional (3D) shapes for multi-sided electrode arrays. We report an innovative self-assembly technology that allows for implementing flexible origami neural probes as an effective alternative to overcome these challenges. By using magnetic-field-assisted hybrid self-assembly, multiple probes with various modalities can be stacked on top of each other with precise alignment. Using this approach, we demonstrated a multifunctional device with scalable high-density recording sites, dopamine sensors and a temperature sensor integrated on a single flexible probe. Simultaneous large-scale, high-spatial-resolution electrophysiology was demonstrated along with local temperature sensing and dopamine concentration monitoring. A high-density 3D origami probe was assembled by wrapping planar probes around a thin fiber in a diameter of 80∼105 μm using optimal foldable design and capillary force. Directional optogenetic modulation could be achieved with illumination from the neuron-sized micro-LEDs (μLEDs) integrated on the surface of 3D origami probes. We could identify angular heterogeneous single-unit signals and neural connectivity 360° surrounding the probe. The probe longevity was validated by chronic recordings of 64-channel stacked probes in behaving mice for up to 140 days. With the modular, customizable assembly technologies presented, we demonstrated a novel and highly flexible solution to accommodate multifunctional integration, channel scaling, and 3D array configuration.
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3
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Richie J, Letner JG, Mclane-Svoboda A, Huan Y, Ghaffari DH, Valle ED, Patel PR, Chiel HJ, Pelled G, Weiland JD, Chestek CA. Fabrication and Validation of Sub-Cellular Carbon Fiber Electrodes. IEEE Trans Neural Syst Rehabil Eng 2024; 32:739-749. [PMID: 38294928 PMCID: PMC10919889 DOI: 10.1109/tnsre.2024.3360866] [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] [Indexed: 02/02/2024]
Abstract
Multielectrode arrays for interfacing with neurons are of great interest for a wide range of medical applications. However, current electrodes cause damage over time. Ultra small carbon fibers help to address issues but controlling the electrode site geometry is difficult. Here we propose a methodology to create small, pointed fiber electrodes (SPFe). We compare the SPFe to previously made blowtorched fibers in characterization. The SPFe result in small site sizes [Formula: see text] with consistently sharp points (20.8 ± 7.64°). Additionally, these electrodes were able to record and/or stimulate neurons multiple animal models including rat cortex, mouse retina, Aplysia ganglia and octopus axial cord. In rat cortex, these electrodes recorded significantly higher peak amplitudes than the traditional blowtorched fibers. These SPFe may be applicable to a wide range of applications requiring a highly specific interface with individual neurons.
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4
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Salman IM. Key challenges in exploring the rat as a preclinical neurostimulation model for aortic baroreflex modulation in hypertension. Hypertens Res 2024; 47:399-415. [PMID: 37919429 DOI: 10.1038/s41440-023-01486-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/02/2023] [Accepted: 10/06/2023] [Indexed: 11/04/2023]
Abstract
Electrode-based electrophysiological interfaces with peripheral nerves have come a long way since the 1960s, with several neurostimulation applications witnessing widespread clinical implementation since then. In resistant hypertension, previous clinical trials have shown that "carotid" baroreflex stimulation using device-based baroreflex activation therapy (BAT) can effectively lower blood pressure (BP). However, device-based "aortic" baroreflex stimulation remains untouched for clinical translation. The rat is a remarkable animal model that facilitates exploration of mechanisms pertaining to the baroreceptor reflex and preclinical development of novel therapeutic strategies for BP modulation and hypertension treatment. Specifically, the aortic depressor nerve (ADN) in rats carries a relatively pure population of barosensitive afferent neurons, which enable selective investigation of the aortic baroreflex function. In a rat model of essential hypertension, the spontaneously hypertensive rat (SHR), we have recently investigated the aortic baroreceptor afferents as an alternate target for BP modulation, and showed that "low intensity" stimulation is able to evoke clinically meaningful reductions in BP. Deriving high quality short-term and long-term data on aortic baroreflex modulation in rats is currently hampered by a number of unresolved experimental challenges, including anatomical variations across rats which complicates identification of the ADN, the use of unrefined neurostimulation tools or paradigms, and issues arising from anesthetized and conscious surgical preparations. With the goal of refining existing experimental protocols designed for preclinical investigation of the baroreflex, this review seeks to outline current challenges hindering further progress in aortic baroreflex modulation studies in rats and present some practical considerations and recently emerging ideas to overcome them. Aortic baroreflex modulation.
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Affiliation(s)
- Ibrahim M Salman
- Department of Pharmaceutical Sciences, College of Pharmacy, Alfaisal University, Riyadh, Saudi Arabia.
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5
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Roche AD, Bailey ZK, Gonzalez M, Vu PP, Chestek CA, Gates DH, Kemp SWP, Cederna PS, Ortiz-Catalan M, Aszmann OC. Upper limb prostheses: bridging the sensory gap. J Hand Surg Eur Vol 2023; 48:182-190. [PMID: 36649123 PMCID: PMC9996795 DOI: 10.1177/17531934221131756] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Replacing human hand function with prostheses goes far beyond only recreating muscle movement with feedforward motor control. Natural sensory feedback is pivotal for fine dexterous control and finding both engineering and surgical solutions to replace this complex biological function is imperative to achieve prosthetic hand function that matches the human hand. This review outlines the nature of the problems underlying sensory restitution, the engineering methods that attempt to address this deficit and the surgical techniques that have been developed to integrate advanced neural interfaces with biological systems. Currently, there is no single solution to restore sensory feedback. Rather, encouraging animal models and early human studies have demonstrated that some elements of sensation can be restored to improve prosthetic control. However, these techniques are limited to highly specialized institutions and much further work is required to reproduce the results achieved, with the goal of increasing availability of advanced closed loop prostheses that allow sensory feedback to inform more precise feedforward control movements and increase functionality.
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Affiliation(s)
- Aidan D Roche
- College of Medicine, The Queen's Medical Research Institute, Edinburgh, UK.,Department of Plastic Surgery, NHS Lothian, Livingston, UK
| | - Zachary K Bailey
- Department of Bioengineering, Imperial College London, South Kensington Campus, UK
| | | | - Philip P Vu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Section of Plastic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Cynthia A Chestek
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Section of Plastic Surgery, University of Michigan, Ann Arbor, MI, USA.,Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Deanna H Gates
- Robotics Institute, University of Michigan, Ann Arbor, MI, USA.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,School of Kinesiology, University of Michigan, Ann Arbor, MI, USA
| | - Stephen W P Kemp
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Section of Plastic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Paul S Cederna
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.,Section of Plastic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Max Ortiz-Catalan
- Center for Bionics and Pain Research, Mölndal, Sweden.,Department of Electrical Engineering, Chalmers University of Technology, Sweden.,Operational Area 3, Sahlgrenska University Hospital, Mölndal, Sweden.,Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - Oskar C Aszmann
- Department of Plastic & Reconstructive Surgery, Medical University of Vienna, Austria.,Clinical Laboratory for Bionic Extremity Reconstruction, Medical University of Vienna, Austria
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6
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Saleh MS, Ritchie SM, Nicholas MA, Gordon HL, Hu C, Jahan S, Yuan B, Bezbaruah R, Reddy JW, Ahmed Z, Chamanzar M, Yttri EA, Panat RP. CMU Array: A 3D nanoprinted, fully customizable high-density microelectrode array platform. SCIENCE ADVANCES 2022; 8:eabj4853. [PMID: 36197979 PMCID: PMC9534502 DOI: 10.1126/sciadv.abj4853] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 08/17/2022] [Indexed: 05/27/2023]
Abstract
Microelectrode arrays provide the means to record electrophysiological activity critical to brain research. Despite its fundamental role, there are no means to customize electrode layouts to address specific experimental or clinical needs. Moreover, current electrodes demonstrate substantial limitations in coverage, fragility, and expense. Using a 3D nanoparticle printing approach that overcomes these limitations, we demonstrate the first in vivo recordings from electrodes that make use of the flexibility of the 3D printing process. The customizable and physically robust 3D multi-electrode devices feature high electrode densities (2600 channels/cm2 of footprint) with minimal gross tissue damage and excellent signal-to-noise ratio. This fabrication methodology also allows flexible reconfiguration consisting of different individual shank lengths and layouts, with low overall channel impedances. This is achieved, in part, via custom 3D printed multilayer circuit boards, a fabrication advancement itself that can support several biomedical device possibilities. This effective device design enables both targeted and large-scale recording of electrical signals throughout the brain.
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Affiliation(s)
- Mohammad Sadeq Saleh
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Sandra M. Ritchie
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Mark A. Nicholas
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Center for the Neural Basis of Cognition, Carnegie Mellon University and University of Pittsburgh, PA 15213, USA
| | - Hailey L. Gordon
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Chunshan Hu
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Sanjida Jahan
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Bin Yuan
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Rriddhiman Bezbaruah
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Jay W. Reddy
- Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Zabir Ahmed
- Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Maysamreza Chamanzar
- Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Eric A. Yttri
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Carnegie Mellon Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Rahul P. Panat
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Carnegie Mellon Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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7
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Williams NP, Kushwah N, Dhawan V, Zheng XS, Cui XT. Effects of central nervous system electrical stimulation on non-neuronal cells. Front Neurosci 2022; 16:967491. [PMID: 36188481 PMCID: PMC9521315 DOI: 10.3389/fnins.2022.967491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 08/10/2022] [Indexed: 11/13/2022] Open
Abstract
Over the past few decades, much progress has been made in the clinical use of electrical stimulation of the central nervous system (CNS) to treat an ever-growing number of conditions from Parkinson's disease (PD) to epilepsy as well as for sensory restoration and many other applications. However, little is known about the effects of microstimulation at the cellular level. Most of the existing research focuses on the effects of electrical stimulation on neurons. Other cells of the CNS such as microglia, astrocytes, oligodendrocytes, and vascular endothelial cells have been understudied in terms of their response to stimulation. The varied and critical functions of these cell types are now beginning to be better understood, and their vital roles in brain function in both health and disease are becoming better appreciated. To shed light on the importance of the way electrical stimulation as distinct from device implantation impacts non-neuronal cell types, this review will first summarize common stimulation modalities from the perspective of device design and stimulation parameters and how these different parameters have an impact on the physiological response. Following this, what is known about the responses of different cell types to different stimulation modalities will be summarized, drawing on findings from both clinical studies as well as clinically relevant animal models and in vitro systems.
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Affiliation(s)
- Nathaniel P. Williams
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States
| | - Neetu Kushwah
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Vaishnavi Dhawan
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States
| | - Xin Sally Zheng
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
- Center for the Neural Basis of Cognition, Pittsburgh, PA, United States
- McGowan Institute for Regenerative Medicine, Pittsburgh, PA, United States
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8
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Zhang B, Deng C, Cai C, Li X. In Vivo Neural Interfaces—From Small- to Large-Scale Recording. FRONTIERS IN NANOTECHNOLOGY 2022. [DOI: 10.3389/fnano.2022.885411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Brain functions arise from the coordinated activation of neuronal assemblies distributed across multiple brain regions. The electrical potential from the neuron captured by the electrode can be processed to extract brain information. A large number of densely and simultaneously recorded neuronal potential signals from neurons spanning multiple brain regions contribute to the insight of specific behaviors encoded by the neural ensembles. In this review, we focused on the neural interfaces developed for small- to large-scale recordings and discussed the developmental challenges and strategies in microsystem, electrode device, and interface material levels for the future larger-scale neural ensemble recordings.
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9
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Yan D, Jiman AA, Bottorff EC, Patel PR, Meli D, Welle EJ, Ratze DC, Havton LA, Chestek CA, Kemp SWP, Bruns TM, Yoon E, Seymour JP. Ultraflexible and Stretchable Intrafascicular Peripheral Nerve Recording Device with Axon-Dimension, Cuff-Less Microneedle Electrode Array. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2200311. [PMID: 35491522 PMCID: PMC9167574 DOI: 10.1002/smll.202200311] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 03/08/2022] [Indexed: 05/03/2023]
Abstract
Peripheral nerve mapping tools with higher spatial resolution are needed to advance systems neuroscience, and potentially provide a closed-loop biomarker in neuromodulation applications. Two critical challenges of microscale neural interfaces are 1) how to apply them to small peripheral nerves, and 2) how to minimize chronic reactivity. A flexible microneedle nerve array (MINA) is developed, which is the first high-density penetrating electrode array made with axon-sized silicon microneedles embedded in low-modulus thin silicone. The design, fabrication, acute recording, and chronic reactivity to an implanted MINA, are presented. Distinctive units are identified in the rat peroneal nerve. The authors also demonstrate a long-term, cuff-free, and suture-free fixation manner using rose bengal as a light-activated adhesive for two time-points. The tissue response is investigated at 1-week and 6-week time-points, including two sham groups and two MINA-implanted groups. These conditions are quantified in the left vagus nerve of rats using histomorphometry. Micro computed tomography (micro-CT) is added to visualize and quantify tissue encapsulation around the implant. MINA demonstrates a reduction in encapsulation thickness over previously quantified interfascicular methods. Future challenges include techniques for precise insertion of the microneedle electrodes and demonstrating long-term recording.
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Affiliation(s)
- Dongxiao Yan
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ahmad A Jiman
- Department of Electrical and Computer Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Elizabeth C Bottorff
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Paras R Patel
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Dilara Meli
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Elissa J Welle
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - David C Ratze
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Leif A Havton
- Departments of Neurology and Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- James J Peters Veterans Affairs Medical Center, Bronx, NY, 10468, USA
| | - Cynthia A Chestek
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Stephen W P Kemp
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
- Section of Plastic Surgery, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Tim M Bruns
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Euisik Yoon
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
- Center for Nanomedicine, Institute for Basic Science (IBS) and Graduate Program of Nano Biomedical Engineering (Nano BME), Advanced Science Institute, Yonsei University, Seoul, South Korea
| | - John P Seymour
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Neurosurgery, UTHealth, Houston, TX, 77030, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, 77030, USA
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10
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Liang C, Liu Y, Lu W, Tian G, Zhao Q, Yang D, Sun J, Qi D. Strategies for interface issues and challenges of neural electrodes. NANOSCALE 2022; 14:3346-3366. [PMID: 35179152 DOI: 10.1039/d1nr07226a] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Neural electrodes, as a bridge for bidirectional communication between the body and external devices, are crucial means for detecting and controlling nerve activity. The electrodes play a vital role in monitoring the state of neural systems or influencing it to treat disease or restore functions. To achieve high-resolution, safe and long-term stable nerve recording and stimulation, a neural electrode with excellent electrochemical performance (e.g., impedance, charge storage capacity, charge injection limit), and good biocompatibility and stability is required. Here, the charge transfer process in the tissues, the electrode-tissue interfaces and the electrode materials are discussed respectively. Subsequently, the latest research methods and strategies for improving the electrochemical performance and biocompatibility of neural electrodes are reviewed. Finally, the challenges in the development of neural electrodes are proposed. It is expected that the development of neural electrodes will offer new opportunities for the evolution of neural prosthesis, bioelectronic medicine, brain science, and so on.
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Affiliation(s)
- Cuiyuan Liang
- National and Local Joint Engineering Laboratory for Synthesis, Transformation and Separation of Extreme Environmental Nutrients, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Yan Liu
- National and Local Joint Engineering Laboratory for Synthesis, Transformation and Separation of Extreme Environmental Nutrients, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Weihong Lu
- National and Local Joint Engineering Laboratory for Synthesis, Transformation and Separation of Extreme Environmental Nutrients, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Gongwei Tian
- National and Local Joint Engineering Laboratory for Synthesis, Transformation and Separation of Extreme Environmental Nutrients, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Qinyi Zhao
- National and Local Joint Engineering Laboratory for Synthesis, Transformation and Separation of Extreme Environmental Nutrients, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Dan Yang
- National and Local Joint Engineering Laboratory for Synthesis, Transformation and Separation of Extreme Environmental Nutrients, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Jing Sun
- National and Local Joint Engineering Laboratory for Synthesis, Transformation and Separation of Extreme Environmental Nutrients, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
| | - Dianpeng Qi
- National and Local Joint Engineering Laboratory for Synthesis, Transformation and Separation of Extreme Environmental Nutrients, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
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11
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Roh H, Yoon YJ, Park JS, Kang DH, Kwak SM, Lee BC, Im M. Fabrication of High-Density Out-of-Plane Microneedle Arrays with Various Heights and Diverse Cross-Sectional Shapes. NANO-MICRO LETTERS 2021; 14:24. [PMID: 34888758 PMCID: PMC8656445 DOI: 10.1007/s40820-021-00778-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/16/2021] [Indexed: 06/01/2023]
Abstract
Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine interface. This work presents a novel but simple method to fabricate high-density silicon (Si) microneedle arrays with various heights and diverse cross-sectional shapes depending on photomask pattern designs. The proposed fabrication method is composed of a single photolithography and two subsequent deep reactive ion etching (DRIE) steps. First, a photoresist layer was patterned on a Si substrate to define areas to be etched, which will eventually determine the final location and shape of each individual microneedle. Then, the 1st DRIE step created deep trenches with a highly anisotropic etching of the Si substrate. Subsequently, the photoresist was removed for more isotropic etching; the 2nd DRIE isolated and sharpened microneedles from the predefined trench structures. Depending on diverse photomask designs, the 2nd DRIE formed arrays of microneedles that have various height distributions, as well as diverse cross-sectional shapes across the substrate. With these simple steps, high-aspect ratio microneedles were created in the high density of up to 625 microneedles mm-2 on a Si wafer. Insertion tests showed a small force as low as ~ 172 µN/microneedle is required for microneedle arrays to penetrate the dura mater of a mouse brain. To demonstrate a feasibility of drug delivery application, we also implemented silk microneedle arrays using molding processes. The fabrication method of the present study is expected to be broadly applicable to create microneedle structures for drug delivery, neuroprosthetic devices, and so on.
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Affiliation(s)
- Hyeonhee Roh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea
- Division of Electrical Engineering, College of Engineering, Korea University, Seoul, 02841, South Korea
| | - Young Jun Yoon
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea
| | - Jin Soo Park
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea
- Division of Electrical Engineering, College of Engineering, Korea University, Seoul, 02841, South Korea
| | - Dong-Hyun Kang
- Micro/Nano Fabrication Center, KIST, Seoul, 02792, South Korea
| | - Seung Min Kwak
- Micro/Nano Fabrication Center, KIST, Seoul, 02792, South Korea
| | - Byung Chul Lee
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea
| | - Maesoon Im
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, South Korea.
- Division of Bio-Medical Science & Technology, KIST School, University of Science & Technology (UST), Seoul, 02792, South Korea.
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12
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Nawaz A, Liu Q, Leong WL, Fairfull-Smith KE, Sonar P. Organic Electrochemical Transistors for In Vivo Bioelectronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2101874. [PMID: 34606146 DOI: 10.1002/adma.202101874] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 07/09/2021] [Indexed: 06/13/2023]
Abstract
Organic electrochemical transistors (OECTs) are presently a focus of intense research and hold great potential in expanding the horizons of the bioelectronics industry. The notable characteristics of OECTs, including their electrolyte-gating, which offers intimate interfacing with biological environments, and aqueous stability, make them particularly suitable to be operated within a living organism (in vivo). Unlike the existing in vivo bioelectronic devices, mostly based on rigid metal electrodes, OECTs form a soft mechanical contact with the biological milieu and ensure a high signal-to-noise ratio because of their powerful amplification capability. Such features make OECTs particularly desirable for a wide range of in vivo applications, including electrophysiological recordings, neuron stimulation, and neurotransmitter detection, and regulation of plant processes in vivo. In this review, a systematic compilation of the in vivo applications is presented that are addressed by the OECT technology. First, the operating mechanisms, and the device design and materials design principles of OECTs are examined, and then multiple examples are provided from the literature while identifying the unique device properties that enable the application progress. Finally, one critically looks at the future of the OECT technology for in vivo bioelectronic applications.
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Affiliation(s)
- Ali Nawaz
- Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, Curitiba, PR, 81531-990, Brazil
- Center for Sensors and Devices, Bruno Kessler Foundation (FBK), Trento, 38123, Italy
| | - Qian Liu
- School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, QLD, 4000, Australia
| | - Wei Lin Leong
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Kathryn E Fairfull-Smith
- School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, QLD, 4000, Australia
- Centre for Materials Science, Queensland University of Technology, 2 George Street, Brisbane, QLD, 4000, Australia
| | - Prashant Sonar
- School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, QLD, 4000, Australia
- Centre for Materials Science, Queensland University of Technology, 2 George Street, Brisbane, QLD, 4000, Australia
- Centre for Biomedical Technologies, Queensland University of Technology, 2 George Street, Brisbane, QLD, 4000, Australia
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13
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Park Y, Chung TS, Lee G, Rogers JA. Materials Chemistry of Neural Interface Technologies and Recent Advances in Three-Dimensional Systems. Chem Rev 2021; 122:5277-5316. [PMID: 34739219 DOI: 10.1021/acs.chemrev.1c00639] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Advances in materials chemistry and engineering serve as the basis for multifunctional neural interfaces that span length scales from individual neurons to neural networks, neural tissues, and complete neural systems. Such technologies exploit electrical, electrochemical, optical, and/or pharmacological modalities in sensing and neuromodulation for fundamental studies in neuroscience research, with additional potential to serve as routes for monitoring and treating neurodegenerative diseases and for rehabilitating patients. This review summarizes the essential role of chemistry in this field of research, with an emphasis on recently published results and developing trends. The focus is on enabling materials in diverse device constructs, including their latest utilization in 3D bioelectronic frameworks formed by 3D printing, self-folding, and mechanically guided assembly. A concluding section highlights key challenges and future directions.
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Affiliation(s)
- Yoonseok Park
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois 60208, United States
| | - Ted S Chung
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois 60208, United States.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Geumbee Lee
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois 60208, United States
| | - John A Rogers
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois 60208, United States.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208, United States.,Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.,Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Department of Neurological Surgery, Northwestern University, Evanston, Illinois 60208, United States
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14
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Frederick RA, Troyk PR, Cogan SF. Wireless microelectrode arrays for selective and chronically stable peripheral nerve stimulation for hindlimb movement. J Neural Eng 2021; 18:10.1088/1741-2552/ac2bb8. [PMID: 34592725 PMCID: PMC10685740 DOI: 10.1088/1741-2552/ac2bb8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/30/2021] [Indexed: 11/12/2022]
Abstract
Objective. Maximizing the stability of implanted neural interfaces will be critical to developing effective treatments for neurological and neuromuscular disorders. Our research aims to develop a stable neural interface using wireless communication and intrafascicular microelectrodes to provide highly selective stimulation of neural tissue.Approach. We implanted a wireless floating microelectrode array into the left sciatic nerve of six rats. Over a 38 week implantation period, we recorded stimulation thresholds and movements evoked at each implanted electrode. We also tracked each animal's response to sensory stimuli and performance on two different walking tasks.Main results. Presence of the microelectrode array inside the sciatic nerve did not cause any obvious motor or sensory deficits in the hindlimb. Visible movement in the hindlimb was evoked by stimulating the sciatic nerve with currents as low as 4.1µA. Thresholds for most of the 96 electrodes we implanted were below 20µA, and predictable recruitment of plantar flexion and dorsiflexion was achieved by stimulating rat sciatic nerve with the intrafascicular microelectrode array. Further, motor recruitment patterns for each electrode did not change significantly throughout the study.Significance. Incorporating wireless communication and a low-profile neural interface facilitated highly stable motor recruitment thresholds and fine motor control in the hindlimb throughout an extensive 9.5 month assessment in rodent peripheral nerve. Results of this study indicate that use of the wireless device tested here could be extended to other applications requiring selective neural stimulation and chronic implantation.
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Affiliation(s)
- Rebecca A Frederick
- Bioengineering Department, The University of Texas at Dallas, Richardson, TX, United States of America
| | - Philip R Troyk
- Biomedical Engineering Department, Illinois Institute of Technology, Chicago, IL, United States of America
| | - Stuart F Cogan
- Bioengineering Department, The University of Texas at Dallas, Richardson, TX, United States of America
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15
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Mian SY, Honey JR, Carnicer-Lombarte A, Barone DG. Large Animal Studies to Reduce the Foreign Body Reaction in Brain-Computer Interfaces: A Systematic Review. BIOSENSORS 2021; 11:275. [PMID: 34436077 PMCID: PMC8392711 DOI: 10.3390/bios11080275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 01/08/2023]
Abstract
Brain-computer interfaces (BCI) are reliant on the interface between electrodes and neurons to function. The foreign body reaction (FBR) that occurs in response to electrodes in the brain alters this interface and may pollute detected signals, ultimately impeding BCI function. The size of the FBR is influenced by several key factors explored in this review; namely, (a) the size of the animal tested, (b) anatomical location of the BCI, (c) the electrode morphology and coating, (d) the mechanics of electrode insertion, and (e) pharmacological modification (e.g., drug eluting electrodes). Trialing methods to reduce FBR in vivo, particularly in large models, is important to enable further translation in humans, and we systematically reviewed the literature to this effect. The OVID, MEDLINE, EMBASE, SCOPUS and Scholar databases were searched. Compiled results were analysed qualitatively. Out of 8388 yielded articles, 13 were included for analysis, with most excluded studies experimenting on murine models. Cats, rabbits, and a variety of breeds of minipig/marmoset were trialed. On average, over 30% reduction in inflammatory cells of FBR on post mortem histology was noted across intervention groups. Similar strategies to those used in rodent models, including tip modification and flexible and sinusoidal electrode configurations, all produced good effects in histology; however, a notable absence of trials examining the effect on BCI end-function was noted. Future studies should assess whether the reduction in FBR correlates to an improvement in the functional effect of the intended BCI.
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Affiliation(s)
- Shan Yasin Mian
- Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London SW7 2BX, UK
| | - Jonathan Roy Honey
- School of Clinical Medicine, University of Cambridge, Cambridge CB3 0DF, UK;
| | | | - Damiano Giuseppe Barone
- Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB3 0DF, UK;
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16
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Raspopovic S, Valle G, Petrini FM. Sensory feedback for limb prostheses in amputees. NATURE MATERIALS 2021; 20:925-939. [PMID: 33859381 DOI: 10.1038/s41563-021-00966-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 02/22/2021] [Indexed: 06/12/2023]
Abstract
Commercial prosthetic devices currently do not provide natural sensory information on the interaction with objects or movements. The subsequent disadvantages include unphysiological walking with a prosthetic leg and difficulty in controlling the force exerted with a prosthetic hand, thus creating health issues. Restoring natural sensory feedback from the prosthesis to amputees is an unmet clinical need. An optimal device should be able to elicit natural sensations of touch or proprioception, by delivering the complex signals to the nervous system that would be produced by skin, muscles and joints receptors. This Review covers the various neurotechnological approaches that have been proposed for the development of the optimal sensory feedback restoration device for arm and leg amputees.
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Affiliation(s)
- Stanisa Raspopovic
- Laboratory for Neuroengineering, Department of Health Sciences and Technology, Institute for Robotics and Intelligent Systems, ETH Zürich, Zurich, Switzerland.
| | - Giacomo Valle
- Laboratory for Neuroengineering, Department of Health Sciences and Technology, Institute for Robotics and Intelligent Systems, ETH Zürich, Zurich, Switzerland
| | - Francesco Maria Petrini
- Laboratory for Neuroengineering, Department of Health Sciences and Technology, Institute for Robotics and Intelligent Systems, ETH Zürich, Zurich, Switzerland
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17
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Welle EJ, Woods JE, Jiman AA, Richie JM, Bottorff EC, Ouyang Z, Seymour JP, Patel PR, Bruns TM, Chestek CA. Sharpened and Mechanically Durable Carbon Fiber Electrode Arrays for Neural Recording. IEEE Trans Neural Syst Rehabil Eng 2021; 29:993-1003. [PMID: 34014825 PMCID: PMC8459724 DOI: 10.1109/tnsre.2021.3082056] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Bioelectric medicine treatments target disorders of the nervous system unresponsive to pharmacological methods. While current stimulation paradigms effectively treat many disorders, the underlying mechanisms are relatively unknown, and current neuroscience recording electrodes are often limited in their specificity to gross averages across many neurons or axons. Here, we develop a novel, durable carbon fiber electrode array adaptable to many neural structures for precise neural recording. Carbon fibers ( [Formula: see text] diameter) were sharpened using a reproducible blowtorchmethod that uses the reflection of fibers against the surface of a water bath. The arrays were developed by partially embedding carbon fibers in medical-grade silicone to improve durability. We recorded acute spontaneous electrophysiology from the rat cervical vagus nerve (CVN), feline dorsal root ganglia (DRG), and rat brain. Blowtorching resulted in fibers of 72.3 ± 33.5-degree tip angle with [Formula: see text] exposed carbon. Observable neural clusters were recorded using sharpened carbon fiber electrodes fromrat CVN ( [Formula: see text]), feline DRG ( [Formula: see text]), and rat brain ( [Formula: see text]). Recordings from the feline DRG included physiologically relevant signals from increased bladder pressure and cutaneous brushing. These results suggest that this carbon fiber array is a uniquely durable and adaptable neural recordingdevice. In the future, this device may be useful as a bioelectric medicine tool for diagnosis and closed-loop neural control of therapeutic treatments and monitoring systems.
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18
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Long Y, Li J, Yang F, Wang J, Wang X. Wearable and Implantable Electroceuticals for Therapeutic Electrostimulations. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2004023. [PMID: 33898184 PMCID: PMC8061371 DOI: 10.1002/advs.202004023] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/20/2020] [Indexed: 05/21/2023]
Abstract
Wearable and implantable electroceuticals (WIEs) for therapeutic electrostimulation (ES) have become indispensable medical devices in modern healthcare. In addition to functionality, device miniaturization, conformability, biocompatibility, and/or biodegradability are the main engineering targets for the development and clinical translation of WIEs. Recent innovations are mainly focused on wearable/implantable power sources, advanced conformable electrodes, and efficient ES on targeted organs and tissues. Herein, nanogenerators as a hotspot wearable/implantable energy-harvesting technique suitable for powering WIEs are reviewed. Then, electrodes for comfortable attachment and efficient delivery of electrical signals to targeted tissue/organ are introduced and compared. A few promising application directions of ES are discussed, including heart stimulation, nerve modulation, skin regeneration, muscle activation, and assistance to other therapeutic modalities.
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Affiliation(s)
- Yin Long
- Department of Material Science and EngineeringUniversity of Wisconsin–MadisonMadisonWI53706USA
| | - Jun Li
- Department of Material Science and EngineeringUniversity of Wisconsin–MadisonMadisonWI53706USA
| | - Fan Yang
- Department of Material Science and EngineeringUniversity of Wisconsin–MadisonMadisonWI53706USA
| | - Jingyu Wang
- Department of Material Science and EngineeringUniversity of Wisconsin–MadisonMadisonWI53706USA
| | - Xudong Wang
- Department of Material Science and EngineeringUniversity of Wisconsin–MadisonMadisonWI53706USA
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19
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Sperry ZJ, Na K, Jun J, Madden LR, Socha A, Yoon E, Seymour JP, Bruns TM. High-density neural recordings from feline sacral dorsal root ganglia with thin-film array. J Neural Eng 2021; 18. [PMID: 33545709 DOI: 10.1088/1741-2552/abe398] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 02/05/2021] [Indexed: 12/26/2022]
Abstract
Objective. Dorsal root ganglia (DRG) are promising sites for recording sensory activity. Current technologies for DRG recording are stiff and typically do not have sufficient site density for high-fidelity neural data techniques.Approach. In acute experiments, we demonstrate single-unit neural recordings in sacral DRG of anesthetized felines using a 4.5µm thick, high-density flexible polyimide microelectrode array with 60 sites and 30-40µm site spacing. We delivered arrays into DRG with ultrananocrystalline diamond shuttles designed for high stiffness affording a smaller footprint. We recorded neural activity during sensory activation, including cutaneous brushing and bladder filling, as well as during electrical stimulation of the pudendal nerve and anal sphincter. We used specialized neural signal analysis software to sort densely packed neural signals.Main results. We successfully delivered arrays in five of six experiments and recorded single-unit sensory activity in four experiments. The median neural signal amplitude was 55μV peak-to-peak and the maximum unique units recorded at one array position was 260, with 157 driven by sensory or electrical stimulation. In one experiment, we used the neural analysis software to track eight sorted single units as the array was retracted ∼500μm.Significance. This study is the first demonstration of ultrathin, flexible, high-density electronics delivered into DRG, with capabilities for recording and tracking sensory information that are a significant improvement over conventional DRG interfaces.
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Affiliation(s)
- Zachariah J Sperry
- Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Kyounghwan Na
- Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States of America
| | - James Jun
- Flatiron Institute, Simons Foundation, New York City, NY, United States of America
| | - Lauren R Madden
- Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Alec Socha
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America.,Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States of America
| | - Eusik Yoon
- Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America.,Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States of America.,Center for Nanomedicine, Institute for Basic Science (IBS) and Graduate Program of Nano Biomedical Engineering (NanoBME), Advanced Science Institute, Yonsei University, Seoul, Republic of Korea
| | - John P Seymour
- Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America.,Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States of America.,University of Texas Health Science Center, Department of Neurosurgery, Houston, TX, United States of America.,Department of Electrical and Computer Engineering, Rice University, Houston, TX, United States of America
| | - Tim M Bruns
- Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
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20
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Llerena Zambrano B, Renz AF, Ruff T, Lienemann S, Tybrandt K, Vörös J, Lee J. Soft Electronics Based on Stretchable and Conductive Nanocomposites for Biomedical Applications. Adv Healthc Mater 2021; 10:e2001397. [PMID: 33205564 DOI: 10.1002/adhm.202001397] [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: 08/08/2020] [Revised: 10/08/2020] [Indexed: 12/15/2022]
Abstract
Research on the field of implantable electronic devices that can be directly applied in the body with various functionalities is increasingly intensifying due to its great potential for various therapeutic applications. While conventional implantable electronics generally include rigid and hard conductive materials, their surrounding biological objects are soft and dynamic. The mechanical mismatch between implanted devices and biological environments induces damages in the body especially for long-term applications. Stretchable electronics with outstanding mechanical compliance with biological objects effectively improve such limitations of existing rigid implantable electronics. In this article, the recent progress of implantable soft electronics based on various conductive nanocomposites is systematically described. In particular, representative fabrication approaches of conductive and stretchable nanocomposites for implantable soft electronics and various in vivo applications of implantable soft electronics are focused on. To conclude, challenges and perspectives of current implantable soft electronics that should be considered for further advances are discussed.
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Affiliation(s)
- Byron Llerena Zambrano
- Laboratory of Biosensors and Bioelectronics ETH Zurich Gloriastrasse 35 Zurich 8092 Switzerland
| | - Aline F. Renz
- Laboratory of Biosensors and Bioelectronics ETH Zurich Gloriastrasse 35 Zurich 8092 Switzerland
| | - Tobias Ruff
- Laboratory of Biosensors and Bioelectronics ETH Zurich Gloriastrasse 35 Zurich 8092 Switzerland
| | - Samuel Lienemann
- Laboratory of Organic Electronics Department of Science and Technology Linköping University Norrköping 601 74 Sweden
| | - Klas Tybrandt
- Laboratory of Organic Electronics Department of Science and Technology Linköping University Norrköping 601 74 Sweden
| | - János Vörös
- Laboratory of Biosensors and Bioelectronics ETH Zurich Gloriastrasse 35 Zurich 8092 Switzerland
| | - Jaehong Lee
- Department of Robotics Engineering Daegu Gyeongbuk Institute of Science and Technology (DGIST) 333 Techno jungan‐dareo Daegu 42988 South Korea
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21
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Ghazavi A, González-González MA, Romero-Ortega MI, Cogan SF. Intraneural ultramicroelectrode arrays for function-specific interfacing to the vagus nerve. Biosens Bioelectron 2020; 170:112608. [PMID: 33035896 PMCID: PMC7654841 DOI: 10.1016/j.bios.2020.112608] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 09/01/2020] [Accepted: 09/09/2020] [Indexed: 11/22/2022]
Abstract
Selective interfacing to small multifunctional nerves such as the vagus nerve (VN) which is the main multimodal autonomic nerve that provides a major communication pathway from vital peripheral organs to the brain, can have significant potential in treating and diagnosing diseases as well as enhancing our understanding of peripheral nerve circuits. Here we describe the fabrication of a 16-channel intraneural electrode array with ultramicro-dimensioned electrodes to achieve improved functionally selective recording. We demonstrate that the amorphous silicon carbide ultramicroelectrode arrays (a-SiC UMEAs) provide selectivity in the detection of neural activity in the cVN related to changes in systemic oxygenation and blood pressure. We will also demonstrate spatially selective recording of micro-compound action potentials (μCAPs) by electrical stimulation of the subdiaphragmatic branches of the VN. Distinct neural activity was recorded on electrodes separated by less than about 100 μm. This is the first time that this level of spatially selectivity recording has been demonstrated in the cVN with an intraneural multielectrode array.
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Affiliation(s)
- Atefeh Ghazavi
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA
| | | | - Mario I Romero-Ortega
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Stuart F Cogan
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, 75080, USA.
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22
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Jiman AA, Ratze DC, Welle EJ, Patel PR, Richie JM, Bottorff EC, Seymour JP, Chestek CA, Bruns TM. Multi-channel intraneural vagus nerve recordings with a novel high-density carbon fiber microelectrode array. Sci Rep 2020; 10:15501. [PMID: 32968177 PMCID: PMC7511947 DOI: 10.1038/s41598-020-72512-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/27/2020] [Indexed: 01/03/2023] Open
Abstract
Autonomic nerves convey essential neural signals that regulate vital body functions. Recording clearly distinctive physiological neural signals from autonomic nerves will help develop new treatments for restoring regulatory functions. However, this is very challenging due to the small nature of autonomic nerves and the low-amplitude signals from their small axons. We developed a multi-channel, high-density, intraneural carbon fiber microelectrode array (CFMA) with ultra-small electrodes (8-9 µm in diameter, 150-250 µm in length) for recording physiological action potentials from small autonomic nerves. In this study, we inserted CFMA with up to 16 recording carbon fibers in the cervical vagus nerve of 22 isoflurane-anesthetized rats. We recorded action potentials with peak-to-peak amplitudes of 15.1-91.7 µV and signal-to-noise ratios of 2.0-8.3 on multiple carbon fibers per experiment, determined conduction velocities of some vagal signals in the afferent (0.7-4.4 m/s) and efferent (0.7-8.8 m/s) directions, and monitored firing rate changes in breathing and blood glucose modulated conditions. Overall, these experiments demonstrated that CFMA is a novel interface for in-vivo intraneural action potential recordings. This work is considerable progress towards the comprehensive understanding of physiological neural signaling in vital regulatory functions controlled by autonomic nerves.
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Affiliation(s)
- Ahmad A Jiman
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Electrical and Computer Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - David C Ratze
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
| | - Elissa J Welle
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Paras R Patel
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Julianna M Richie
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Elizabeth C Bottorff
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - John P Seymour
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
- Department of Neurosurgery, University of Texas Health Science Center, Houston, TX, USA
| | - Cynthia A Chestek
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
| | - Tim M Bruns
- Department of Biomedical Engineering, University of Michigan, NCRC - B10 - A-169, 2800 Plymouth Road, Ann Arbor, MI, 48109, USA.
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.
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23
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Otchy TM, Michas C, Lee B, Gopalan K, Nerurkar V, Gleick J, Semu D, Darkwa L, Holinski BJ, Chew DJ, White AE, Gardner TJ. Printable microscale interfaces for long-term peripheral nerve mapping and precision control. Nat Commun 2020; 11:4191. [PMID: 32826892 PMCID: PMC7442820 DOI: 10.1038/s41467-020-18032-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 07/29/2020] [Indexed: 12/28/2022] Open
Abstract
The nascent field of bioelectronic medicine seeks to decode and modulate peripheral nervous system signals to obtain therapeutic control of targeted end organs and effectors. Current approaches rely heavily on electrode-based devices, but size scalability, material and microfabrication challenges, limited surgical accessibility, and the biomechanically dynamic implantation environment are significant impediments to developing and deploying peripheral interfacing technologies. Here, we present a microscale implantable device - the nanoclip - for chronic interfacing with fine peripheral nerves in small animal models that begins to meet these constraints. We demonstrate the capability to make stable, high signal-to-noise ratio recordings of behaviorally-linked nerve activity over multi-week timescales. In addition, we show that multi-channel, current-steering-based stimulation within the confines of the small device can achieve multi-dimensional control of a small nerve. These results highlight the potential of new microscale design and fabrication techniques for realizing viable devices for long-term peripheral interfacing.
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Affiliation(s)
- Timothy M Otchy
- Department of Biology, Boston University, Boston, MA, 02215, USA.
- Neurophotonics Center, Boston University, Boston, MA, 02215, USA.
- Center for Systems Neuroscience, Boston University, Boston, MA, 02215, USA.
| | - Christos Michas
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Blaire Lee
- Department of Biology, Boston University, Boston, MA, 02215, USA
| | - Krithi Gopalan
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Vidisha Nerurkar
- Department of Biology, Boston University, Boston, MA, 02215, USA
| | - Jeremy Gleick
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Dawit Semu
- Department of Biology, Boston University, Boston, MA, 02215, USA
| | - Louis Darkwa
- Department of Biology, Boston University, Boston, MA, 02215, USA
| | - Bradley J Holinski
- Bioelectronics Division, GlaxoSmithKline, Stevenage, Hertfordshire, SG1 2NY, UK
| | - Daniel J Chew
- Bioelectronics Division, GlaxoSmithKline, Stevenage, Hertfordshire, SG1 2NY, UK
| | - Alice E White
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
- Department of Mechanical Engineering, Boston University, Boston, MA, 02215, USA
| | - Timothy J Gardner
- Department of Biology, Boston University, Boston, MA, 02215, USA.
- Neurophotonics Center, Boston University, Boston, MA, 02215, USA.
- Center for Systems Neuroscience, Boston University, Boston, MA, 02215, USA.
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA.
- Knight Campus, University of Oregon, Eugene, OR, 97405, USA.
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Guo T, Chen L, Tran K, Ghelich P, Guo YS, Nolta N, Emadi S, Han M, Feng B. Extracellular single-unit recordings from peripheral nerve axons in vitro by a novel multichannel microelectrode array. SENSORS AND ACTUATORS. B, CHEMICAL 2020; 315:128111. [PMID: 32494111 PMCID: PMC7269151 DOI: 10.1016/j.snb.2020.128111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The peripheral nervous system (PNS) is an attractive target for modulation of afferent input (e.g., nociceptive input signaling tissue damage) to the central nervous system. To advance mechanistic understanding of PNS neural encoding and modulation requires single-unit recordings from individual peripheral neurons or axons. This is challenged by multiple connective tissue layers surrounding peripheral nerve fibers that prevent electrical recordings by existing electrodes or electrode arrays. In this study, we developed a novel microelectrode array (MEA) via silicon-based microfabrication that consists of 5 parallel hydrophilic gold electrodes surrounded by silanized hydrophobic surfaces. This novel hydrophilic/hydrophobic surface pattern guides the peripheral nerve filaments to self-align towards the hydrophilic electrodes, which dramatically reduces the technical challenges in conducting single-unit recordings. We validated our MEA by recording simultaneous single-unit action potentials from individual axons in mouse sciatic nerves, including both myelinated A-fibers and unmyelinated C-fibers. We confirmed that our recordings were single units from individual axons by increasing nerve trunk electrical stimulus intensity, which did not alter the spike shape or amplitude. By reducing the technical challenges, our novel MEA will likely allow peripheral single-unit recordings to be adopted by a larger research community and thus expedite our mechanistic understanding of peripheral neural encoding and modulation.
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Affiliation(s)
- Tiantian Guo
- Department of Biomedical Engineering, University of Connecticut, CT 06269, USA
| | - Longtu Chen
- Department of Biomedical Engineering, University of Connecticut, CT 06269, USA
| | - Khanh Tran
- Department of Biomedical Engineering, University of Connecticut, CT 06269, USA
| | - Pejman Ghelich
- Department of Biomedical Engineering, University of Connecticut, CT 06269, USA
| | - Yi-Syuan Guo
- Department of Biomedical Engineering, University of Connecticut, CT 06269, USA
| | - Nicholas Nolta
- Department of Biomedical Engineering, University of Connecticut, CT 06269, USA
| | - Sharareh Emadi
- Department of Biomedical Engineering, University of Connecticut, CT 06269, USA
| | - Martin Han
- Department of Biomedical Engineering, University of Connecticut, CT 06269, USA
| | - Bin Feng
- Department of Biomedical Engineering, University of Connecticut, CT 06269, USA
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25
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Shah AR, Khan MS, Hirahara AM, Lange M, Ranjan R, Dosdall DJ. In Vitro/Ex Vivo Investigation of Modified Utah Electrode Array to Selectively Sense and Pace the Sub-Surface Cardiac His Bundle. ACS Biomater Sci Eng 2020; 6:3335-3348. [PMID: 32715084 DOI: 10.1021/acsbiomaterials.0c00065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Utah Electrode Arrays (UEAs) have previously been characterized and implanted for neural recordings and stimulation at relatively low current levels. This proof-of-concept study investigated the applicability of UEAs in sub-surface cardiac pacing, for the first time, particularly to selectively sense and pace the His-Bundle (HB). HB pacing produces synchronous ventricular depolarization and improved cardiac function. Modified UEAs with sputtered iridium oxide film (SIROF) tips (100 - 150 μm) were characterized for SIROF delamination using an electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and voltage transient (VT) techniques at various current levels of up to 8 mA for a biphasic pulse with 1 ms duration per phase at 4 Hz. Our results indicate that at a short pacing duration of 20 s with current levels of up to 4 mA, the SIROF exhibited a strong charge-transfer performance. For the longer pacing duration (6 min), SIROF demonstrated its holding capacity at all current levels except for ≥2 mA when delamination commenced for the time exceeded 4 min (EIS) and 2 min (VT). UEAs were inserted in isolated, perfused goat hearts to record the HB electrograms in real-time. Both stimulated and unstimulated electrodes were characterized for SIROF delamination before, during and after in vivo work. Our findings indicate that UEA was stable during the heart's contraction and relaxation phase. Further, at a short pacing duration with current levels of up to 4 mA, UEA demonstrated high selectively in sensing the HB. This proof-of-concept work demonstrates the potential applicability of UEAs in cardiac applications.
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Affiliation(s)
- Ankur R Shah
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Muhammad S Khan
- Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Annie M Hirahara
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Matthias Lange
- Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Ravi Ranjan
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA.,Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Utah, Salt Lake City, UT 84112, USA
| | - Derek J Dosdall
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA.,Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Utah, Salt Lake City, UT 84112, USA.,Division of Cardiothoracic Surgery, Department of Surgery, The University of Utah, Salt Lake City, UT 84112, USA
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26
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Na K, Sperry ZJ, Lu J, Vöröslakos M, Parizi SS, Bruns TM, Yoon E, Seymour JP. Novel diamond shuttle to deliver flexible neural probe with reduced tissue compression. MICROSYSTEMS & NANOENGINEERING 2020; 6:37. [PMID: 32528723 PMCID: PMC7261651 DOI: 10.1038/s41378-020-0149-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/21/2019] [Accepted: 01/15/2020] [Indexed: 05/05/2023]
Abstract
The ability to deliver flexible biosensors through the toughest membranes of the central and peripheral nervous system is an important challenge in neuroscience and neural engineering. Bioelectronic devices implanted through dura mater and thick epineurium would ideally create minimal compression and acute damage as they reach the neurons of interest. We demonstrate that a three-dimensional diamond shuttle can be easily made with a vertical support to deliver ultra-compliant polymer microelectrodes (4.5-µm thick) through dura mater and thick epineurium. The diamond shuttle has 54% less cross-sectional area than an equivalently stiff silicon shuttle, which we simulated will result in a 37% reduction in blood vessel damage. We also discovered that higher frequency oscillation of the shuttle (200 Hz) significantly reduced tissue compression regardless of the insertion speed, while slow speeds also independently reduced tissue compression. Insertion and recording performance are demonstrated in rat and feline models, but the large design space of these tools are suitable for research in a variety of animal models and nervous system targets.
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Affiliation(s)
- Kyounghwan Na
- Electrical Engineering & Computer Science Department, University of Michigan, Ann Arbor, MI 48105 USA
| | - Zachariah J. Sperry
- Biomedical Engineering Department, University of Michigan, Ann Arbor, MI 48105 USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48105 USA
| | - Jiaao Lu
- Electrical Engineering & Computer Science Department, University of Michigan, Ann Arbor, MI 48105 USA
| | - Mihaly Vöröslakos
- Electrical Engineering & Computer Science Department, University of Michigan, Ann Arbor, MI 48105 USA
- The Neuroscience Institute, New York University, New York, NY 10016 USA
| | - Saman S. Parizi
- Electrical Engineering & Computer Science Department, University of Michigan, Ann Arbor, MI 48105 USA
| | - Tim M. Bruns
- Biomedical Engineering Department, University of Michigan, Ann Arbor, MI 48105 USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48105 USA
| | - Euisik Yoon
- Electrical Engineering & Computer Science Department, University of Michigan, Ann Arbor, MI 48105 USA
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul, 03722 Korea
- Graduate Program of Nano Biomedical Engineering (Nano BME), Yonsei-IBS Institute, Yonsei University, Seoul, 03722 Korea
| | - John P. Seymour
- Electrical Engineering & Computer Science Department, University of Michigan, Ann Arbor, MI 48105 USA
- Vivian L Smith Department of Neurosurgery, University of Texas Health Science Center, Houston, TX 77030 USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005 USA
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27
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Song E, Li J, Won SM, Bai W, Rogers JA. Materials for flexible bioelectronic systems as chronic neural interfaces. NATURE MATERIALS 2020; 19:590-603. [PMID: 32461684 DOI: 10.1038/s41563-020-0679-7] [Citation(s) in RCA: 159] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/09/2020] [Indexed: 05/03/2023]
Abstract
Engineered systems that can serve as chronically stable, high-performance electronic recording and stimulation interfaces to the brain and other parts of the nervous system, with cellular-level resolution across macroscopic areas, are of broad interest to the neuroscience and biomedical communities. Challenges remain in the development of biocompatible materials and the design of flexible implants for these purposes, where ulimate goals are for performance attributes approaching those of conventional wafer-based technologies and for operational timescales reaching the human lifespan. This Review summarizes recent advances in this field, with emphasis on active and passive constituent materials, design architectures and integration methods that support necessary levels of biocompatibility, electronic functionality, long-term stable operation in biofluids and reliability for use in vivo. Bioelectronic systems that enable multiplexed electrophysiological mapping across large areas at high spatiotemporal resolution are surveyed, with a particular focus on those with proven chronic stability in live animal models and scalability to thousands of channels over human-brain-scale dimensions. Research in materials science will continue to underpin progress in this field of study.
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Affiliation(s)
- Enming Song
- Center for Bio-Integrated Electronics, Northwestern University, Evanston, IL, USA
| | - Jinghua Li
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, USA
- Center for Chronic Brain Injury, The Ohio State University, Columbus, OH, USA
| | - Sang Min Won
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Wubin Bai
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA
| | - John A Rogers
- Center for Bio-Integrated Electronics, Northwestern University, Evanston, IL, USA.
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA.
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
- Department of Neurological Surgery, Northwestern University, Evanston, IL, USA.
- Department of Chemistry, Northwestern University, Evanston, IL, USA.
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA.
- Department of Electrical Engineering, Northwestern University, Evanston, IL, USA.
- Department of Computer Science, Northwestern University, Evanston, IL, USA.
- Feinberg School of Medicine, Northwestern University, Evanston, IL, USA.
- Querrey-Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA.
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28
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Yildiz KA, Shin AY, Kaufman KR. Interfaces with the peripheral nervous system for the control of a neuroprosthetic limb: a review. J Neuroeng Rehabil 2020; 17:43. [PMID: 32151268 PMCID: PMC7063740 DOI: 10.1186/s12984-020-00667-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 02/17/2020] [Indexed: 12/22/2022] Open
Abstract
The field of prosthetics has been evolving and advancing over the past decade, as patients with missing extremities are expecting to control their prostheses in as normal a way as possible. Scientists have attempted to satisfy this expectation by designing a connection between the nervous system of the patient and the prosthetic limb, creating the field of neuroprosthetics. In this paper, we broadly review the techniques used to bridge the patient's peripheral nervous system to a prosthetic limb. First, we describe the electrical methods including myoelectric systems, surgical innovations and the role of nerve electrodes. We then describe non-electrical methods used alone or in combination with electrical methods. Design concerns from an engineering point of view are explored, and novel improvements to obtain a more stable interface are described. Finally, a critique of the methods with respect to their long-term impacts is provided. In this review, nerve electrodes are found to be one of the most promising interfaces in the future for intuitive user control. Clinical trials with larger patient populations, and for longer periods of time for certain interfaces, will help to evaluate the clinical application of nerve electrodes.
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Affiliation(s)
- Kadir A Yildiz
- Motion Analysis Laboratory, Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Alexander Y Shin
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Kenton R Kaufman
- Motion Analysis Laboratory, Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA.
- Motion Analysis Laboratory, W. Hall Wendel, Jr., Musculoskeletal Research, 200 First Street SW, Rochester, MN, 55905, USA.
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29
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A review for the peripheral nerve interface designer. J Neurosci Methods 2019; 332:108523. [PMID: 31743684 DOI: 10.1016/j.jneumeth.2019.108523] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 12/11/2022]
Abstract
Informational density and relative accessibility of the peripheral nervous system make it an attractive site for therapeutic intervention. Electrode-based electrophysiological interfaces with peripheral nerves have been under development since the 1960s and, for several applications, have seen widespread clinical implementation. However, many applications require a combination of neural target resolution and stability which has thus far eluded existing peripheral nerve interfaces (PNIs). With the goal of aiding PNI designers in development of devices that meet the demands of next-generation applications, this review seeks to collect and present practical considerations and best practices which emerge from the literature, including both lessons learned during early PNI development and recent ideas. Fundamental and practical principles guiding PNI design are reviewed, followed by an updated and critical account of existing PNI designs and strategies. Finally, a brief survey of in vitro and in vivo PNI characterization methods is presented.
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30
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Tam WK, Wu T, Zhao Q, Keefer E, Yang Z. Human motor decoding from neural signals: a review. BMC Biomed Eng 2019; 1:22. [PMID: 32903354 PMCID: PMC7422484 DOI: 10.1186/s42490-019-0022-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 07/21/2019] [Indexed: 01/24/2023] Open
Abstract
Many people suffer from movement disability due to amputation or neurological diseases. Fortunately, with modern neurotechnology now it is possible to intercept motor control signals at various points along the neural transduction pathway and use that to drive external devices for communication or control. Here we will review the latest developments in human motor decoding. We reviewed the various strategies to decode motor intention from human and their respective advantages and challenges. Neural control signals can be intercepted at various points in the neural signal transduction pathway, including the brain (electroencephalography, electrocorticography, intracortical recordings), the nerves (peripheral nerve recordings) and the muscles (electromyography). We systematically discussed the sites of signal acquisition, available neural features, signal processing techniques and decoding algorithms in each of these potential interception points. Examples of applications and the current state-of-the-art performance were also reviewed. Although great strides have been made in human motor decoding, we are still far away from achieving naturalistic and dexterous control like our native limbs. Concerted efforts from material scientists, electrical engineers, and healthcare professionals are needed to further advance the field and make the technology widely available in clinical use.
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Affiliation(s)
- Wing-kin Tam
- Department of Biomedical Engineering, University of Minnesota Twin Cities, 7-105 Hasselmo Hall, 312 Church St. SE, Minnesota, 55455 USA
| | - Tong Wu
- Department of Biomedical Engineering, University of Minnesota Twin Cities, 7-105 Hasselmo Hall, 312 Church St. SE, Minnesota, 55455 USA
| | - Qi Zhao
- Department of Computer Science and Engineering, University of Minnesota Twin Cities, 4-192 Keller Hall, 200 Union Street SE, Minnesota, 55455 USA
| | - Edward Keefer
- Nerves Incorporated, Dallas, TX P. O. Box 141295 USA
| | - Zhi Yang
- Department of Biomedical Engineering, University of Minnesota Twin Cities, 7-105 Hasselmo Hall, 312 Church St. SE, Minnesota, 55455 USA
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31
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Lee Y, Kong C, Chang JW, Jun SB. Carbon-Fiber Based Microelectrode Array Embedded with a Biodegradable Silk Support for In Vivo Neural Recording. J Korean Med Sci 2019; 34:e24. [PMID: 30686948 PMCID: PMC6345632 DOI: 10.3346/jkms.2019.34.e24] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 12/13/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Recently, carbon fibers have been utilized to develop a depth-type microelectrode array for chronic neural recording. Since the diameter of carbon fibers is smaller than the conventional electrodes made of metal wires or microfabricated silicon, the carbon fiber electrodes showed an improved capability for chronic neural recording with less tissue damages. However, the carbon fiber based microelectrodes have a limitation of short insertion depth due to a low stiffness. METHODS We proposed a carbon fiber based microelectrode array embedded with a mechanical support structure to facilitate the penetration into the deeper brain. The support is made of biodegradable silk fibroin to reduce the reactive tissue responses. The 4-channel carbon fiber based microelectrode arrays were fabricated and accessed in terms of electrochemical impedance, recording capability for 1-month implantation in rat hippocampi. The electrodes with tungsten supports were fabricated and tested as a control group. Immunohistochemical analysis was performed to identify the reactive glial responses. RESULTS The carbon fiber based electrode arrays with silk supports showed about 2-fold impedance increase 2 weeks after implantation while the number of active electrodes decreased simultaneously. However, after 1 month, the electrode impedance decreased back to its initial value and the percentage of active electrodes also increased above 70%. Immunohistochemical staining clearly showed that the electrodes with silk supports induced less reactive glial responses than that with tungsten supports. CONCLUSION The proposed carbon fiber based microelectrode array is expected to be used for long-term in vivo neural recording from deep brain regions with the minimized reactive tissue response.
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Affiliation(s)
- Yena Lee
- Department of Electronic and Electrical Engineering, ELTEC College of Engineering, Ewha Womans University, Seoul, Korea
| | - Chanho Kong
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
| | - Jin Woo Chang
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea
| | - Sang Beom Jun
- Department of Electronic and Electrical Engineering, ELTEC College of Engineering, Ewha Womans University, Seoul, Korea
- Department of Brain and Cognitive Science, College of Scranton, Ewha Womans University, Seoul, Korea
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32
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Advances in Penetrating Multichannel Microelectrodes Based on the Utah Array Platform. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1101:1-40. [PMID: 31729670 DOI: 10.1007/978-981-13-2050-7_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The Utah electrode array (UEA) and its many derivatives have become a gold standard for high-channel count bi-directional neural interfaces, in particular in human subject applications. The chapter provides a brief overview of leading electrode concepts and the context in which the UEA has to be understood. It goes on to discuss the key advances and developments of the UEA platform in the past 15 years, as well as novel wireless and system integration technologies that will merge into future generations of fully integrated devices. Aspects covered include novel device architectures that allow scaling of channel count and density of electrode contacts, material improvements to substrate, electrode contacts, and encapsulation. Further subjects are adaptations of the UEA platform to support IR and optogenetic simulation as well as an improved understanding of failure modes and methods to test and accelerate degradation in vitro such as to better predict device failure and lifetime in vivo.
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33
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Choi JR, Kim SM, Ryu RH, Kim SP, Sohn JW. Implantable Neural Probes for Brain-Machine Interfaces - Current Developments and Future Prospects. Exp Neurobiol 2018; 27:453-471. [PMID: 30636899 PMCID: PMC6318554 DOI: 10.5607/en.2018.27.6.453] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 12/14/2022] Open
Abstract
A Brain-Machine interface (BMI) allows for direct communication between the brain and machines. Neural probes for recording neural signals are among the essential components of a BMI system. In this report, we review research regarding implantable neural probes and their applications to BMIs. We first discuss conventional neural probes such as the tetrode, Utah array, Michigan probe, and electroencephalography (ECoG), following which we cover advancements in next-generation neural probes. These next-generation probes are associated with improvements in electrical properties, mechanical durability, biocompatibility, and offer a high degree of freedom in practical settings. Specifically, we focus on three key topics: (1) novel implantable neural probes that decrease the level of invasiveness without sacrificing performance, (2) multi-modal neural probes that measure both electrical and optical signals, (3) and neural probes developed using advanced materials. Because safety and precision are critical for practical applications of BMI systems, future studies should aim to enhance these properties when developing next-generation neural probes.
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Affiliation(s)
- Jong-Ryul Choi
- Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF), Daegu 41061, Korea
| | - Seong-Min Kim
- Department of Medical Science, College of Medicine, Catholic Kwandong University, Gangneung 25601, Korea.,Biomedical Research Institute, Catholic Kwandong University International St. Mary's Hospital, Incheon 21711, Korea
| | - Rae-Hyung Ryu
- Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF), Daegu 41061, Korea
| | - Sung-Phil Kim
- Department of Human Factors Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Jeong-Woo Sohn
- Department of Medical Science, College of Medicine, Catholic Kwandong University, Gangneung 25601, Korea.,Biomedical Research Institute, Catholic Kwandong University International St. Mary's Hospital, Incheon 21711, Korea
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34
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Silveira C, Brunton E, Spendiff S, Nazarpour K. Positioning the Nerve Cuff Distally on the Sciatic Nerve Improves the Classification of Ankle-Movement Proprioceptive ENG Signals. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:2430-2433. [PMID: 30440898 DOI: 10.1109/embc.2018.8512751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recording of neural signals from intact peripheral nerves in patients with spinal cord injury or stroke survivors offers the possibility for the development of closed-loop sensorimotor prostheses. However, questions remain over the positioning of neural interfaces such that the separability of neural data recorded from the peripheral nerves is improved. Afferent electroneurographic signals were recorded with nerve cuffs placed on the sciatic nerve of rats in response to various mechanical stimuli to the hindpaw. The mean absolute value of the signal was extracted and fed into classifiers. The performance of the classifier was evaluated when information was available from a single cuff placed either distally or proximally on the sciatic nerve. Results confirmed earlier findings that proprioceptive ENG signals, elicited by the movement of the ankle, can be identified and separated in neural recordings made with a cuff electrode. In addition, classification scores improved when the nerve cuff was placed distally on the nerve rather than proximally, taking advantage of the nerve's underlying anatomy.
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35
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Hope J, Vanholsbeeck F, McDaid A. Drive and measurement electrode patterns for electrode impedance tomography (EIT) imaging of neural activity in peripheral nerve. Biomed Phys Eng Express 2018; 4. [DOI: 10.1088/2057-1976/aadff3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 09/10/2018] [Indexed: 11/12/2022]
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36
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Effects of Synchronous Electrode Pulses on Neural Recruitment During Multichannel Microstimulation. Sci Rep 2018; 8:13067. [PMID: 30166583 PMCID: PMC6117337 DOI: 10.1038/s41598-018-31247-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 08/09/2018] [Indexed: 11/22/2022] Open
Abstract
The recent proliferation of high-density microelectrode arrays has inspired several new applications of electrical microstimulation, including restoration of sensory functions in the visual, auditory, and somatosensory systems. In each case, the goal is to achieve precisely targeted activation of neurons, while patterning the location and timing of stimulation across the array to mimic naturalistic patterns of neural activity. However, when two or more electrodes deliver stimulation pulses at the same time, the electric fields created by each electrode interact. The effects of field interactions on neuronal recruitment depend on several factors, which have been studied extensively at the macro-scale but have been overlooked in the case of high density arrays. Here, we report that field interactions can significantly affect neural recruitment, even with low amplitude stimulation. We created a computational model of peripheral nerve axons to estimate stimulation parameters sufficient to generate neural recruitment during synchronous and asynchronous stimulation on two microelectrodes located within the peripheral nerve. Across a range of stimulus amplitudes, the model predicted that synchronous stimulation on adjacent electrodes (400 µm separation), would recruit 2–3 times more neurons than during asynchronous stimulation. Our results suggest that field interactions should not be ignored when designing multichannel microstimulation paradigms, even at threshold-level stimulus amplitudes.
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37
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Caldwell R, Mandal H, Sharma R, Solzbacher F, Tathireddy P, Rieth L. Analysis of Al 2O 3-parylene C bilayer coatings and impact of microelectrode topography on long term stability of implantable neural arrays. J Neural Eng 2018; 14:046011. [PMID: 28351998 DOI: 10.1088/1741-2552/aa69d3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Performance of many dielectric coatings for neural electrodes degrades over time, contributing to loss of neural signals and evoked percepts. Studies using planar test substrates have found that a novel bilayer coating of atomic-layer deposited (ALD) Al2O3 and parylene C is a promising candidate for neural electrode applications, exhibiting superior stability to parylene C alone. However, initial results from bilayer encapsulation testing on non-planar devices have been less positive. Our aim was to evaluate ALD Al2O3-parylene C coatings using novel test paradigms, to rigorously evaluate dielectric coatings for neural electrode applications by incorporating neural electrode topography into test structure design. APPROACH Five test devices incorporated three distinct topographical features common to neural electrodes, derived from the utah electrode array (UEA). Devices with bilayer (52 nm Al2O3 + 6 µm parylene C) were evaluated against parylene C controls (N ⩾ 6 per device type). Devices were aged in phosphate buffered saline at 67 °C for up to 311 d, and monitored through: (1) leakage current to evaluate encapsulation lifetimes (>1 nA during 5VDC bias indicated failure), and (2) wideband (1-105 Hz) impedance. MAIN RESULTS Mean-times-to-failure (MTTFs) ranged from 12 to 506 d for bilayer-coated devices, versus 10 to >2310 d for controls. Statistical testing (log-rank test, α = 0.05) of failure rates gave mixed results but favored the control condition. After failure, impedance loss for bilayer devices continued for months and manifested across the entire spectrum, whereas the effect was self-limiting after several days, and restricted to frequencies <100 Hz for controls. These results correlated well with observations of UEAs encapsulated with bilayer and control films. SIGNIFICANCE We observed encapsulation failure modes and behaviors comparable to neural electrode performance which were undetected in studies with planar test devices. We found the impact of parylene C defects to be exacerbated by ALD Al2O3, and conclude that inferior bilayer performance arises from degradation of ALD Al2O3 when directly exposed to saline. This is an important consideration, given that neural electrodes with bilayer coatings are expected to have ALD Al2O3 exposed at dielectric boundaries that delineate electrode sites. Process improvements and use of different inorganic coatings to decrease dissolution in physiological fluids may improve performance. Testing frameworks which take neural electrode complexities into account will be well suited to reliably evaluate such encapsulation schemes.
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Affiliation(s)
- Ryan Caldwell
- Department of Bioengineering, University of Utah, Salt Lake City, UT, United States of America
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Won SM, Song E, Zhao J, Li J, Rivnay J, Rogers JA. Recent Advances in Materials, Devices, and Systems for Neural Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1800534. [PMID: 29855089 DOI: 10.1002/adma.201800534] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 02/28/2018] [Indexed: 06/08/2023]
Abstract
Technologies capable of establishing intimate, long-lived optical/electrical interfaces to neural systems will play critical roles in neuroscience research and in the development of nonpharmacological treatments for neurological disorders. The development of high-density interfaces to 3D populations of neurons across entire tissue systems in living animals, including human subjects, represents a grand challenge for the field, where advanced biocompatible materials and engineered structures for electrodes and light emitters will be essential. This review summarizes recent progress in these directions, with an emphasis on the most promising demonstrated concepts, materials, devices, and systems. The article begins with an overview of electrode materials with enhanced electrical and/or mechanical performance, in forms ranging from planar films, to micro/nanostructured surfaces, to 3D porous frameworks and soft composites. Subsequent sections highlight integration with active materials and components for multiplexed addressing, local amplification, wireless data transmission, and power harvesting, with multimodal operation in soft, shape-conformal systems. These advances establish the foundations for scalable architectures in optical/electrical neural interfaces of the future, where a blurring of the lines between biotic and abiotic systems will catalyze profound progress in neuroscience research and in human health/well-being.
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Affiliation(s)
- Sang Min Won
- Department of Electrical and Computer Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Urbana, IL, 61801, USA
| | - Enming Song
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Northwestern University, Evanston, IL, 60208, USA
| | - Jianing Zhao
- Department of Mechanical Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Urbana, IL, 61801, USA
| | - Jinghua Li
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Northwestern University, Evanston, IL, 60208, USA
| | - Jonathan Rivnay
- Department of Biomedical Engineering, Simpson Querrey Institute for Nanobiotechnology, Northwestern University, Evanston, IL, 60208, USA
| | - John A Rogers
- Center for Bio-Integrated Electronics, Department of Materials Science and Engineering, Biomedical Engineering, Chemistry, Mechanical Engineering, Electrical Engineering and Computer Science, and Neurological Surgery, Simpson Querrey Institute for Nano/biotechnology, McCormick School of Engineering and Feinberg School of Medicine, Northwestern University, Evanston, IL, 60208, USA
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Bettinger CJ. Recent advances in materials and flexible electronics for peripheral nerve interfaces. Bioelectron Med 2018; 4:6. [PMID: 32232082 PMCID: PMC7098226 DOI: 10.1186/s42234-018-0007-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/03/2018] [Indexed: 11/10/2022] Open
Abstract
Peripheral nerve interfaces are a central technology in advancing bioelectronic medicines because these medical devices can record and modulate the activity of nerves that innervate visceral organs. Peripheral nerve interfaces that use electrical signals for recording or stimulation have advanced our collective understanding of the peripheral nervous system. Furthermore, devices such as cuff electrodes and multielectrode arrays of various form factors have been implanted in the peripheral nervous system of humans in several therapeutic contexts. Substantive advances have been made using devices composed of off-the-shelf commodity materials. However, there is also a demand for improved device performance including extended chronic reliability, enhanced biocompatibility, and increased bandwidth for recording and stimulation. These aspirational goals manifest as much needed improvements in device performance including: increasing mechanical compliance (reducing Young's modulus and increasing extensibility); improving the barrier properties of encapsulation materials; reducing impedance and increasing the charge injection capacity of electrode materials; and increasing the spatial resolution of multielectrode arrays. These proposed improvements require new materials and novel microfabrication strategies. This mini-review highlights selected recent advances in flexible electronics for peripheral nerve interfaces. The foci of this mini-review include novel materials for flexible and stretchable substrates, non-conventional microfabrication techniques, strategies for improved device packaging, and materials to improve signal transduction across the tissue-electrode interface. Taken together, this article highlights challenges and opportunities in materials science and processing to improve the performance of peripheral nerve interfaces and advance bioelectronic medicine.
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Affiliation(s)
- Christopher J. Bettinger
- 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
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Silveira C, Brunton E, Spendiff S, Nazarpour K. Influence of nerve cuff channel count and implantation site on the separability of afferent ENG. J Neural Eng 2018; 15:046004. [PMID: 29629880 PMCID: PMC5964361 DOI: 10.1088/1741-2552/aabca0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Objective. Recording of neural signals from intact peripheral nerves
in patients with spinal cord injury or stroke survivors offers the possibility for
the development of closed-loop sensorimotor prostheses. Nerve cuffs have been found
to provide stable recordings from peripheral nerves for prolonged periods of time.
However, questions remain over the design and positioning of nerve cuffs such that
the separability of neural data recorded from the peripheral nerves is improved.
Approach. Afferent electroneurographic (ENG) signals were
recorded with nerve cuffs placed on the sciatic nerve of rats in response to various
mechanical stimuli to the hindpaw. The mean absolute value of the signal was
extracted and input to a classifier. The performance of the classifier was evaluated
under two conditions: (1) when information from either a 3- or 16-channel cuff was
used; (2) when information was available from a cuff placed either distally or
proximally along the nerve. Main results. We show that both 3- and
16-channel cuffs were able to separate afferent ENG signals with an accuracy greater
than chance. The highest classification scores were achieved when the classifier was
fed with information obtained from a 16-channel cuff placed distally. While the
16-channel cuff always outperformed the 3-channel cuff, the difference in performance
was increased when the 16-channel cuff was placed distally rather than proximally on
the nerve. Significance. The results indicate that increasing the
complexity of a nerve cuff may only be advantageous if the nerve cuff is to be
implanted distally, where the nerve has begun to divide into individual
fascicles.
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Affiliation(s)
- Carolina Silveira
- Intelligent Sensing Laboratory, School of Engineering, Newcastle University, NE1 7RU, United Kingdom
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41
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Spearman BS, Desai VH, Mobini S, McDermott MD, Graham JB, Otto KJ, Judy JW, Schmidt CE. Tissue-Engineered Peripheral Nerve Interfaces. ADVANCED FUNCTIONAL MATERIALS 2018; 28:1701713. [PMID: 37829558 PMCID: PMC10569514 DOI: 10.1002/adfm.201701713] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Research on neural interfaces has historically concentrated on development of systems for the brain; however, there is increasing interest in peripheral nerve interfaces (PNIs) that could provide benefit when peripheral nerve function is compromised, such as for amputees. Efforts focus on designing scalable and high-performance sensory and motor peripheral nervous system interfaces. Current PNIs face several design challenges such as undersampling of signals from the thousands of axons, nerve-fiber selectivity, and device-tissue integration. To improve PNIs, several researchers have turned to tissue engineering. Peripheral nerve tissue engineering has focused on designing regeneration scaffolds that mimic normal nerve extracellular matrix composition, provide advanced microarchitecture to stimulate cell migration, and have mechanical properties like the native nerve. By combining PNIs with tissue engineering, the goal is to promote natural axon regeneration into the devices to facilitate close contact with electrodes; in contrast, traditional PNIs rely on insertion or placement of electrodes into or around existing nerves, or do not utilize materials to actively facilitate axon regeneration. This review presents the state-of-the-art of PNIs and nerve tissue engineering, highlights recent approaches to combine neural-interface technology and tissue engineering, and addresses the remaining challenges with foreign-body response.
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Affiliation(s)
- Benjamin S Spearman
- Crayton Pruitt Family Department of Biomedical Engineering, The University of Florida, 1275 Center Dr., BMS Building JG-56, 116131, Gainesville, FL 32611-6131
| | - Vidhi H Desai
- Department of Electrical and Computer Engineering, The University of Florida, 216 Larsen Hall, 116200, Gainesville, FL 32611-6200
- Nanoscience Institute for Medical and Engineering Technology, The University of Florida, 1041 Center Drive, 116621, Gainesville, FL 32611-6621
| | - Sahba Mobini
- Crayton Pruitt Family Department of Biomedical Engineering, The University of Florida, 1275 Center Dr., BMS Building JG-56, 116131, Gainesville, FL 32611-6131
| | - Matthew D McDermott
- Crayton Pruitt Family Department of Biomedical Engineering, The University of Florida, 1275 Center Dr., BMS Building JG-56, 116131, Gainesville, FL 32611-6131
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr., West Lafayette, IN 47907-2032
| | - James B Graham
- Crayton Pruitt Family Department of Biomedical Engineering, The University of Florida, 1275 Center Dr., BMS Building JG-56, 116131, Gainesville, FL 32611-6131
| | - Kevin J Otto
- Crayton Pruitt Family Department of Biomedical Engineering, The University of Florida, 1275 Center Dr., BMS Building JG-56, 116131, Gainesville, FL 32611-6131
- Nanoscience Institute for Medical and Engineering Technology, The University of Florida, 1041 Center Drive, 116621, Gainesville, FL 32611-6621
- Department of Neuroscience, The University of Florida, 1149 Newell Dr., Room L1-100, 100244, Gainesville, FL 32610-0244
- Department of Neurology, The University of Florida, 2000 SW Archer Rd., Third Floor, 100383, Gainesville, FL 32610
| | - Jack W Judy
- Crayton Pruitt Family Department of Biomedical Engineering, The University of Florida, 1275 Center Dr., BMS Building JG-56, 116131, Gainesville, FL 32611-6131
- Department of Electrical and Computer Engineering, The University of Florida, 216 Larsen Hall, 116200, Gainesville, FL 32611-6200
- Nanoscience Institute for Medical and Engineering Technology, The University of Florida, 1041 Center Drive, 116621, Gainesville, FL 32611-6621
| | - Christine E Schmidt
- Crayton Pruitt Family Department of Biomedical Engineering, The University of Florida, 1275 Center Dr., BMS Building JG-56, 116131, Gainesville, FL 32611-6131
- Nanoscience Institute for Medical and Engineering Technology, The University of Florida, 1041 Center Drive, 116621, Gainesville, FL 32611-6621
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Thukral A, Ershad F, Enan N, Rao Z, Yu C. Soft Ultrathin Silicon Electronics for Soft Neural Interfaces: A Review of Recent Advances of Soft Neural Interfaces Based on Ultrathin Silicon. IEEE NANOTECHNOLOGY MAGAZINE 2018. [DOI: 10.1109/mnano.2017.2781290] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Anish Thukral
- Mechanical Engineering, University of Houston, Houston, Texas United States
| | - Faheem Ershad
- Biomedical Engineering, University of Houston, Houston, Texas United States
| | - Nada Enan
- Biomedical Engineering, University of Houston, Houston, Texas United States
| | - Zhoulyu Rao
- Materials Science and Engineering, University of Houston, Houston, Texas United States
| | - Cunjiang Yu
- Mechanical Engineering, University of Houston, Houston, Texas United States
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Staples NA, Goding JA, Gilmour AD, Aristovich KY, Byrnes-Preston P, Holder DS, Morley JW, Lovell NH, Chew DJ, Green RA. Conductive Hydrogel Electrodes for Delivery of Long-Term High Frequency Pulses. Front Neurosci 2018; 11:748. [PMID: 29375292 PMCID: PMC5768631 DOI: 10.3389/fnins.2017.00748] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/22/2017] [Indexed: 11/17/2022] Open
Abstract
Nerve block waveforms require the passage of large amounts of electrical energy at the neural interface for extended periods of time. It is desirable that such waveforms be applied chronically, consistent with the treatment of protracted immune conditions, however current metal electrode technologies are limited in their capacity to safely deliver ongoing stable blocking waveforms. Conductive hydrogel (CH) electrode coatings have been shown to improve the performance of conventional bionic devices, which use considerably lower amounts of energy than conventional metal electrodes to replace or augment sensory neuron function. In this study the application of CH materials was explored, using both a commercially available platinum iridium (PtIr) cuff electrode array and a novel low-cost stainless steel (SS) electrode array. The CH was able to significantly increase the electrochemical performance of both array types. The SS electrode coated with the CH was shown to be stable under continuous delivery of 2 mA square pulse waveforms at 40,000 Hz for 42 days. CH coatings have been shown as a beneficial electrode material compatible with long-term delivery of high current, high energy waveforms.
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Affiliation(s)
- Naomi A Staples
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Josef A Goding
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia.,Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Aaron D Gilmour
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Kirill Y Aristovich
- Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Phillip Byrnes-Preston
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - David S Holder
- Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - John W Morley
- School of Medical Science, University of New South Wales, Sydney, NSW, Australia.,School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Nigel H Lovell
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | | | - Rylie A Green
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia.,Department of Bioengineering, Imperial College London, London, United Kingdom
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44
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Tyler DJ. Neuroprostheses for Restoring Sensation. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00103-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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45
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Prospects for a Robust Cortical Recording Interface. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00028-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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46
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Caldwell R, Sharma R, Takmakov P, Street MG, Solzbacher F, Tathireddy P, Rieth L. Neural electrode resilience against dielectric damage may be improved by use of highly doped silicon as a conductive material. J Neurosci Methods 2018; 293:210-225. [DOI: 10.1016/j.jneumeth.2017.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 10/01/2017] [Accepted: 10/02/2017] [Indexed: 11/28/2022]
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47
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Jung R, Abbas JJ, Kuntaegowdanahalli S, Thota AK. Bionic intrafascicular interfaces for recording and stimulating peripheral nerve fibers. ACTA ACUST UNITED AC 2017; 1:55-69. [PMID: 29480906 DOI: 10.2217/bem-2017-0009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 11/13/2017] [Indexed: 12/16/2022]
Abstract
The network of peripheral nerves presents extraordinary potential for modulating and/or monitoring the functioning of internal organs or the brain. The degree to which these pathways can be used to influence or observe neural activity patterns will depend greatly on the quality and specificity of the bionic interface. The anatomical organization, which consists of multiple nerve fibers clustered into fascicles within a nerve bundle, presents opportunities and challenges that may necessitate insertion of electrodes into individual fascicles to achieve the specificity that may be required for many clinical applications. This manuscript reviews the current state-of-the-art in bionic intrafascicular interfaces, presents specific concerns for stimulation and recording, describes key implementation considerations and discusses challenges for future designs of bionic intrafascicular interfaces.
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Affiliation(s)
- Ranu Jung
- Department of Biomedical Engineering, Florida International University, EC2602, 10555 W Flagler Street, Miami, FL 33134, USA.,Department of Biomedical Engineering, Florida International University, EC2602, 10555 W Flagler Street, Miami, FL 33134, USA
| | - James J Abbas
- Center for Adaptive Neural Systems, School of Biological & Health Systems Engineering, PO Box 879709 Arizona State University, Tempe, AZ 85287-9709, USA.,Center for Adaptive Neural Systems, School of Biological & Health Systems Engineering, PO Box 879709 Arizona State University, Tempe, AZ 85287-9709, USA
| | - Sathyakumar Kuntaegowdanahalli
- Department of Biomedical Engineering, Florida International University, EC2602, 10555 W Flagler Street, Miami, FL 33134, USA.,Department of Biomedical Engineering, Florida International University, EC2602, 10555 W Flagler Street, Miami, FL 33134, USA
| | - Anil K Thota
- Department of Biomedical Engineering, Florida International University, EC2602, 10555 W Flagler Street, Miami, FL 33134, USA.,Department of Biomedical Engineering, Florida International University, EC2602, 10555 W Flagler Street, Miami, FL 33134, USA
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48
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de la Oliva N, Navarro X, Del Valle J. Time course study of long-term biocompatibility and foreign body reaction to intraneural polyimide-based implants. J Biomed Mater Res A 2017; 106:746-757. [PMID: 29052368 DOI: 10.1002/jbm.a.36274] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 10/06/2017] [Accepted: 10/17/2017] [Indexed: 12/26/2022]
Abstract
The foreign body reaction (FBR) against an implanted device is characterized by the formation of a fibrotic tissue around the implant. In the case of interfaces for peripheral nerves, used to stimulate specific group of axons and to record different nerve signals, the FBR induces a matrix deposition around the implant creating a physical separation between nerve fibers and the interface that may reduce its functionality over time. In order to understand how the FBR to intraneural interfaces evolves, polyimide non-functional devices were implanted in rat peripheral nerve. Functional tests (electrophysiological, pain and locomotion) and histological evaluation demonstrated that implanted devices did not cause any alteration in nerve function, in myelinated axons or in nerve architecture. The inflammatory response due to the surgical implantation decreased after 2 weeks. In contrast, inflammation was higher and more prolonged in the device implanted nerves with a peak after 2 weeks. With regard to tissue deposition, a tissue capsule appeared soon around the devices, acquiring maximal thickness at 2 weeks and being remodeled subsequently. Immunohistochemical analysis revealed two different cell types implicated in the FBR in the nerve: macrophages as the first cells in contact with the interface and fibroblasts that appear later at the edge of the capsule. Our results describe how the FBR against a polyimide implant in the peripheral nerve occurs and which are the main cellular players. Increasing knowledge of these responses will help to improve strategies to decrease the FBR against intraneural implants and to extend their usability. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 746-757, 2018.
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Affiliation(s)
- Natàlia de la Oliva
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Institute of Neurosciences, Bellaterra, 08193, Barcelona, Spain
| | - Xavier Navarro
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Institute of Neurosciences, Bellaterra, 08193, Barcelona, Spain
| | - Jaume Del Valle
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Institute of Neurosciences, Bellaterra, 08193, Barcelona, Spain.,Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain
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49
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Ghafoor U, Kim S, Hong KS. Selectivity and Longevity of Peripheral-Nerve and Machine Interfaces: A Review. Front Neurorobot 2017; 11:59. [PMID: 29163122 PMCID: PMC5671609 DOI: 10.3389/fnbot.2017.00059] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 10/17/2017] [Indexed: 11/22/2022] Open
Abstract
For those individuals with upper-extremity amputation, a daily normal living activity is no longer possible or it requires additional effort and time. With the aim of restoring their sensory and motor functions, theoretical and technological investigations have been carried out in the field of neuroprosthetic systems. For transmission of sensory feedback, several interfacing modalities including indirect (non-invasive), direct-to-peripheral-nerve (invasive), and cortical stimulation have been applied. Peripheral nerve interfaces demonstrate an edge over the cortical interfaces due to the sensitivity in attaining cortical brain signals. The peripheral nerve interfaces are highly dependent on interface designs and are required to be biocompatible with the nerves to achieve prolonged stability and longevity. Another criterion is the selection of nerves that allows minimal invasiveness and damages as well as high selectivity for a large number of nerve fascicles. In this paper, we review the nerve-machine interface modalities noted above with more focus on peripheral nerve interfaces, which are responsible for provision of sensory feedback. The invasive interfaces for recording and stimulation of electro-neurographic signals include intra-fascicular, regenerative-type interfaces that provide multiple contact channels to a group of axons inside the nerve and the extra-neural-cuff-type interfaces that enable interaction with many axons around the periphery of the nerve. Section Current Prosthetic Technology summarizes the advancements made to date in the field of neuroprosthetics toward the achievement of a bidirectional nerve-machine interface with more focus on sensory feedback. In the Discussion section, the authors propose a hybrid interface technique for achieving better selectivity and long-term stability using the available nerve interfacing techniques.
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Affiliation(s)
- Usman Ghafoor
- School of Mechanical Engineering, Pusan National University, Busan, South Korea
| | - Sohee Kim
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Keum-Shik Hong
- School of Mechanical Engineering, Pusan National University, Busan, South Korea.,Department of Cogno-Mechatronics Engineering, Pusan National University, Busan, South Korea
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50
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Huang YC, Huang PT, Wu SL, Hu YC, You YH, Chen JM, Huang YY, Chang HC, Lin YH, Duann JR, Chiu TW, Hwang W, Chen KN, Chuang CT, Chiou JC. Ultrahigh-Density 256-Channel Neural Sensing Microsystem Using TSV-Embedded Neural Probes. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2017; 11:1013-1025. [PMID: 28371785 DOI: 10.1109/tbcas.2017.2669439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Highly integrated neural sensing microsystems are crucial to capture accurate signals for brain function investigations. In this paper, a 256-channel neural sensing microsystem with a sensing area of 5 × 5 mm 2 is presented based on 2.5-D through-silicon-via (TSV) integration. This microsystem composes of dissolvable μ-needles, TSV-embedded μ-probes, 256-channel neural amplifiers, 11-bit area-power-efficient successive approximation register analog-to-digital converters, and serializers. This microsystem can detect 256 electrocorticography and local field potential signals within a small area of 5 mm × 5 mm. The neural amplifier realizes 57.8 dB gain with only 9.8 μW per channel. The overall power of this microsystem is only 3.79 mW for 256-channel neural sensing. A smaller microsystem with dimension of 6 mm × 4 mm has been also implanted into rat brain for somatosensory evoked potentials (SSEPs) recording by using contralateral and ipsilateral electrical stimuli with intensity from 0.2 to 1.0 mA, and successfully observed different SSEPs from left somatosensory cortex of a rat.
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Affiliation(s)
- Yu-Chieh Huang
- Institute of Electrical Control Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Po-Tsang Huang
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Shang-Lin Wu
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Yu-Chen Hu
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Yan-Huei You
- Institute of Electrical Control Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Jr-Ming Chen
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Yan-Yu Huang
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Hsiao-Chun Chang
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Yen-Han Lin
- Institute of Electrical Control Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Jeng-Ren Duann
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan, R.O.C
| | - Tzai-Wen Chiu
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Wei Hwang
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Kuan-Neng Chen
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Ching-Te Chuang
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Jin-Chern Chiou
- Institute of Electrical Control Engineering and the Department of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
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