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Chandra NS, McCarron WM, Yan Y, Ruiz LC, Sallinger EG, Birenbaum NK, Burton H, Green L, Moran DW, Ray WZ, MacEwan MR. Sensory Percepts Elicited by Chronic Macro-Sieve Electrode Stimulation of the Rat Sciatic Nerve. Front Neurosci 2021; 15:758427. [PMID: 34690689 PMCID: PMC8530229 DOI: 10.3389/fnins.2021.758427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 09/17/2021] [Indexed: 11/30/2022] Open
Abstract
Objective: Intuitive control of conventional prostheses is hampered by their inability to provide the real-time tactile and proprioceptive feedback of natural sensory pathways. The macro-sieve electrode (MSE) is a candidate interface to amputees’ truncated peripheral nerves for introducing sensory feedback from external sensors to facilitate prosthetic control. Its unique geometry enables selective control of the complete nerve cross-section by current steering. Unlike previously studied interfaces that target intact nerve, the MSE’s implantation requires transection and subsequent regeneration of the target nerve. Therefore, a key determinant of the MSE’s suitability for this task is whether it can elicit sensory percepts at low current levels in the face of altered morphology and caliber distribution inherent to axon regeneration. The present in vivo study describes a combined rat sciatic nerve and behavioral model developed to answer this question. Approach: Rats learned a go/no-go detection task using auditory stimuli and then underwent surgery to implant the MSE in the sciatic nerve. After healing, they were trained with monopolar electrical stimuli with one multi-channel and eight single-channel stimulus configurations. Psychometric curves derived by the method of constant stimuli (MCS) were used to calculate 50% detection thresholds and associated psychometric slopes. Thresholds and slopes were calculated at two time points 3 weeks apart. Main Results: For the multi-channel stimulus configuration, the average current required for stimulus detection was 19.37 μA (3.87 nC) per channel. Single-channel thresholds for leads located near the nerve’s center were, on average, half those of leads located near the periphery (54.92 μA vs. 110.71 μA, or 10.98 nC vs. 22.14 nC). Longitudinally, 3 of 5 leads’ thresholds decreased or remained stable over the 3-week span. The remaining two leads’ thresholds increased by 70–74%, possibly due to scarring or device failure. Significance: This work represents an important first step in establishing the MSE’s viability as a sensory feedback interface. It further lays the groundwork for future experiments that will extend this model to the study of other devices, stimulus parameters, and task paradigms.
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Affiliation(s)
- Nikhil S Chandra
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States
| | - Weston M McCarron
- Department of Neurosurgery, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| | - Ying Yan
- Department of Neurosurgery, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| | - Luis C Ruiz
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States
| | - Eric G Sallinger
- Department of Biology, Washington University in St. Louis, St. Louis, MO, United States
| | - Nathan K Birenbaum
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States
| | - Harold Burton
- Department of Neuroscience, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| | - Leonard Green
- Department of Psychological & Brain Sciences, Washington University in St. Louis, St. Louis, MO, United States
| | - Daniel W Moran
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States
| | - Wilson Z Ray
- Department of Neurosurgery, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
| | - Matthew R MacEwan
- Department of Neurosurgery, Washington University School of Medicine in St. Louis, St. Louis, MO, United States
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2
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Veith A, Li X, Modi H, Abbaspour A, Luan L, Xie C, Baker AB. Optimized design of a hyperflexible sieve electrode to enhance neurovascular regeneration for a peripheral neural interface. Biomaterials 2021; 275:120924. [PMID: 34147716 PMCID: PMC9939235 DOI: 10.1016/j.biomaterials.2021.120924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 05/13/2021] [Accepted: 05/23/2021] [Indexed: 11/24/2022]
Abstract
One in 190 Americans is currently living with the loss of a limb resulted from injury, amputation, or neurodegenerative disease. Advanced neuroprosthetic devices combine peripheral neural interfaces with sophisticated prosthetics and hold great potential for the rehabilitation of impaired motor and sensory functions. While robotic prosthetics have advanced very rapidly, peripheral neural interfaces have long been limited by the capability of interfacing with the peripheral nervous system. In this work, we developed a hyperflexible regenerative sieve electrode to serve as a peripheral neural interface. We examined tissue neurovascular integration through this novel device. We demonstrated that we could enhance the neurovascular invasion through the device with directional growth factor delivery. Furthermore, we demonstrated that we could reduce the tissue reaction to the device often seen in peripheral neural interfaces. Finally, we show that we can create a stable tissue device interface in a long-term implantation that does not impede the normal regenerative processes of the nerve. Our study developed an optimal platform for the continued development of hyperflexible sieve electrode peripheral neural interfaces.
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Affiliation(s)
- Austin Veith
- The University of Texas at Austin, Department of Biomedical Engineering, Austin, TX
| | - Xue Li
- Rice University, Department of Electrical and Computer Engineering, Houston, TX
| | - Hailey Modi
- The University of Texas at Austin, Department of Biomedical Engineering, Austin, TX
| | - Ali Abbaspour
- The University of Texas at Austin, Department of Biomedical Engineering, Austin, TX
| | - Lan Luan
- Rice University, Department of Electrical and Computer Engineering, Houston, TX
| | - Chong Xie
- Rice University, Department of Electrical and Computer Engineering, Houston, TX
| | - Aaron B. Baker
- The University of Texas at Austin, Department of Biomedical Engineering, Austin, TX,Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX,Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX,Institute for Biomaterials, Drug Delivery and Regenerative Medicine, The University of Texas at Austin, Austin, TX
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3
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Abstract
Peripheral nerve interfaces (PNIs) record and/or modulate neural activity of nerves, which are responsible for conducting sensory-motor information to and from the central nervous system, and for regulating the activity of inner organs. PNIs are used both in neuroscience research and in therapeutical applications such as precise closed-loop control of neuroprosthetic limbs, treatment of neuropathic pain and restoration of vital functions (e.g. breathing and bladder management). Implantable interfaces represent an attractive solution to directly access peripheral nerves and provide enhanced selectivity both in recording and in stimulation, compared to their non-invasive counterparts. Nevertheless, the long-term functionality of implantable PNIs is limited by tissue damage, which occurs at the implant-tissue interface, and is thus highly dependent on material properties, biocompatibility and implant design. Current research focuses on the development of mechanically compliant PNIs, which adapt to the anatomy and dynamic movements of nerves in the body thereby limiting foreign body response. In this paper, we review recent progress in the development of flexible and implantable PNIs, highlighting promising solutions related to materials selection and their associated fabrication methods, and integrated functions. We report on the variety of available interface designs (intraneural, extraneural and regenerative) and different modulation techniques (electrical, optical, chemical) emphasizing the main challenges associated with integrating such systems on compliant substrates.
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Affiliation(s)
- Valentina Paggi
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland. Equally contributing authors
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Ferrari LM, Rodríguez-Meana B, Bonisoli A, Cutrone A, Micera S, Navarro X, Greco F, Del Valle J. All-Polymer Printed Low-Cost Regenerative Nerve Cuff Electrodes. Front Bioeng Biotechnol 2021; 9:615218. [PMID: 33644015 PMCID: PMC7902501 DOI: 10.3389/fbioe.2021.615218] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 01/11/2021] [Indexed: 11/13/2022] Open
Abstract
Neural regeneration after lesions is still limited by several factors and new technologies are developed to address this issue. Here, we present and test in animal models a new regenerative nerve cuff electrode (RnCE). It is based on a novel low-cost fabrication strategy, called "Print and Shrink", which combines the inkjet printing of a conducting polymer with a heat-shrinkable polymer substrate for the development of a bioelectronic interface. This method allows to produce miniaturized regenerative cuff electrodes without the use of cleanroom facilities and vacuum based deposition methods, thus highly reducing the production costs. To fully proof the electrodes performance in vivo we assessed functional recovery and adequacy to support axonal regeneration after section of rat sciatic nerves and repair with RnCE. We investigated the possibility to stimulate the nerve to activate different muscles, both in acute and chronic scenarios. Three months after implantation, RnCEs were able to stimulate regenerated motor axons and induce a muscular response. The capability to produce fully-transparent nerve interfaces provided with polymeric microelectrodes through a cost-effective manufacturing process is an unexplored approach in neuroprosthesis field. Our findings pave the way to the development of new and more usable technologies for nerve regeneration and neuromodulation.
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Affiliation(s)
- Laura M Ferrari
- Center for Micro-BioRobotics @SSSA, Istituto Italiano di Tecnologia, Pontedera, Italy.,The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pontedera, Italy.,Université Côte d'Azur, INRIA, Sophia Antipolis, France
| | - Bruno Rodríguez-Meana
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, and CIBERNED, Bellaterra, Spain
| | - Alberto Bonisoli
- Center for Micro-BioRobotics @SSSA, Istituto Italiano di Tecnologia, Pontedera, Italy.,The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pontedera, Italy
| | - Annarita Cutrone
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pontedera, Italy
| | - Silvestro Micera
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pontedera, Italy.,Bertarelli Foundation Chair in Translational NeuroEngineering, Center for Neuroprosthetics and Institute of Bioengineering, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
| | - Xavier Navarro
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, and CIBERNED, Bellaterra, Spain
| | - Francesco Greco
- Center for Micro-BioRobotics @SSSA, Istituto Italiano di Tecnologia, Pontedera, Italy.,Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Graz, Austria.,Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Jaume Del Valle
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, and CIBERNED, Bellaterra, Spain
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5
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Zellmer ER, MacEwan MR, Moran DW. Modelling the impact of altered axonal morphometry on the response of regenerative nervous tissue to electrical stimulation through macro-sieve electrodes. J Neural Eng 2019; 15:026009. [PMID: 29192607 DOI: 10.1088/1741-2552/aa9e96] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Regenerated peripheral nervous tissue possesses different morphometric properties compared to undisrupted nerve. It is poorly understood how these morphometric differences alter the response of the regenerated nerve to electrical stimulation. In this work, we use computational modeling to explore the electrophysiological response of regenerated and undisrupted nerve axons to electrical stimulation delivered by macro-sieve electrodes (MSEs). APPROACH A 3D finite element model of a peripheral nerve segment populated with mammalian myelinated axons and implanted with a macro-sieve electrode has been developed. Fiber diameters and morphometric characteristics representative of undisrupted or regenerated peripheral nervous tissue were assigned to core conductor models to simulate the two tissue types. Simulations were carried out to quantify differences in thresholds and chronaxie between undisrupted and regenerated fiber populations. The model was also used to determine the influence of axonal caliber on recruitment thresholds for the two tissue types. Model accuracy was assessed through comparisons with in vivo recruitment data from chronically implanted MSEs. MAIN RESULTS Recruitment thresholds of individual regenerated fibers with diameters >2 µm were found to be lower compared to same caliber undisrupted fibers at electrode to fiber distances of less than about 90-140 µm but roughly equal or higher for larger distances. Caliber redistributions observed in regenerated nerve resulted in an overall increase in average recruitment thresholds and chronaxie during whole nerve stimulation. Modeling results also suggest that large diameter undisrupted fibers located close to a longitudinally restricted current source such as the MSE have higher average recruitment thresholds compared to small diameter fibers. In contrast, large diameter regenerated nerve fibers located in close proximity of MSE sites have, on average, lower recruitment thresholds compared to small fibers. Utilizing regenerated fiber morphometry and caliber distributions resulted in accurate predictions of in vivo recruitment data. SIGNIFICANCE Our work uses computational modeling to show how morphometric differences between regenerated and undisrupted tissue results in recruitment threshold discrepancies, quantifies these differences, and illustrates how large undisrupted nerve fibers close to longitudinally restricted current sources have higher recruitment thresholds compared to adjacently positioned smaller fibers while the opposite is true for large regenerated fibers.
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Affiliation(s)
- Erik R Zellmer
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, United States of America
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6
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Delgado-Martínez I, Righi M, Santos D, Cutrone A, Bossi S, D'Amico S, Del Valle J, Micera S, Navarro X. Fascicular nerve stimulation and recording using a novel double-aisle regenerative electrode. J Neural Eng 2018; 14:046003. [PMID: 28382924 DOI: 10.1088/1741-2552/aa6bac] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE As artificial prostheses become more refined, they are most often used as a therapeutic option for hand amputation. By contrast to extra- or intraneural interfaces, regenerative nerve electrodes are designed to enable electrical interfaces with regrowing axonal bundles of injured nerves, aiming to achieve high selectivity for recording and stimulation. However, most of the developed designs pose an obstacle to the regrowth mechanisms due to low transparency and cause impairment to the nerve regeneration. APPROACH Here we present the double-aisle electrode, a new type of highly transparent, non-obstructive regenerative electrode. Using a double-side thin-film polyimide planar multi-contact electrode, two nerve fascicles can regenerate without physical impairment through two electrically isolated aisles. MAIN RESULTS We show that this electrode can be used to selectively record and stimulate fascicles, acutely as well as chronically, and allow regeneration in nerve gaps of several millimeters without impairment. SIGNIFICANCE This multi-aisle regenerative electrode may be suitable for neuroprosthetic applications, such as prostheses, for the restoration of hand function after amputation or severe nerve injuries.
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Affiliation(s)
- I Delgado-Martínez
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain
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7
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Hong KS, Aziz N, Ghafoor U. Motor-commands decoding using peripheral nerve signals: a review. J Neural Eng 2018; 15:031004. [PMID: 29498358 DOI: 10.1088/1741-2552/aab383] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
During the last few decades, substantial scientific and technological efforts have been focused on the development of neuroprostheses. The major emphasis has been on techniques for connecting the human nervous system with a robotic prosthesis via natural-feeling interfaces. The peripheral nerves provide access to highly processed and segregated neural command signals from the brain that can in principle be used to determine user intent and control muscles. If these signals could be used, they might allow near-natural and intuitive control of prosthetic limbs with multiple degrees of freedom. This review summarizes the history of neuroprosthetic interfaces and their ability to record from and stimulate peripheral nerves. We also discuss the types of interfaces available and their applications, the kinds of peripheral nerve signals that are used, and the algorithms used to decode them. Finally, we explore the prospects for future development in this area.
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8
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MacEwan MR, Zellmer ER, Wheeler JJ, Burton H, Moran DW. Regenerated Sciatic Nerve Axons Stimulated through a Chronically Implanted Macro-Sieve Electrode. Front Neurosci 2016; 10:557. [PMID: 28008303 PMCID: PMC5143347 DOI: 10.3389/fnins.2016.00557] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/21/2016] [Indexed: 01/17/2023] Open
Abstract
Sieve electrodes provide a chronic interface for stimulating peripheral nerve axons. Yet, successful utilization requires robust axonal regeneration through the implanted electrode. The present study determined the effect of large transit zones in enhancing axonal regeneration and revealed an intimate neural interface with an implanted sieve electrode. Fabrication of the polyimide sieve electrodes employed sacrificial photolithography. The manufactured macro-sieve electrode (MSE) contained nine large transit zones with areas of ~0.285 mm2 surrounded by eight Pt-Ir metallized electrode sites. Prior to implantation, saline, or glial derived neurotropic factor (GDNF) was injected into nerve guidance silicone-conduits with or without a MSE. The MSE assembly or a nerve guidance conduit was implanted between transected ends of the sciatic nerve in adult male Lewis rats. At 3 months post-operation, fiber counts were similar through both implant types. Likewise, stimulation of nerves regenerated through a MSE or an open silicone conduit evoked comparable muscle forces. These results showed that nerve regeneration was comparable through MSE transit zones and an open conduit. GDNF had a minimal positive effect on the quality and morphology of fibers regenerating through the MSE; thus, the MSE may reduce reliance on GDNF to augment axonal regeneration. Selective stimulation of several individual muscles was achieved through monopolar stimulation of individual electrodes sites suggesting that the MSE might be an optimal platform for functional neuromuscular stimulation.
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Affiliation(s)
- Matthew R MacEwan
- Department of Biomedical Engineering, Washington University St. Louis, MO, USA
| | - Erik R Zellmer
- Department of Biomedical Engineering, Washington University St. Louis, MO, USA
| | - Jesse J Wheeler
- Department of Biomedical Engineering, Washington University St. Louis, MO, USA
| | - Harold Burton
- Department of Neuroscience, Washington University School of Medicine in St. Louis St. Louis, MO, USA
| | - Daniel W Moran
- Department of Biomedical Engineering, Washington University St. Louis, MO, USA
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9
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Adewole DO, Serruya MD, Harris JP, Burrell JC, Petrov D, Chen HI, Wolf JA, Cullen DK. The Evolution of Neuroprosthetic Interfaces. Crit Rev Biomed Eng 2016; 44:123-52. [PMID: 27652455 PMCID: PMC5541680 DOI: 10.1615/critrevbiomedeng.2016017198] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The ideal neuroprosthetic interface permits high-quality neural recording and stimulation of the nervous system while reliably providing clinical benefits over chronic periods. Although current technologies have made notable strides in this direction, significant improvements must be made to better achieve these design goals and satisfy clinical needs. This article provides an overview of the state of neuroprosthetic interfaces, starting with the design and placement of these interfaces before exploring the stimulation and recording platforms yielded from contemporary research. Finally, we outline emerging research trends in an effort to explore the potential next generation of neuroprosthetic interfaces.
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Affiliation(s)
- Dayo O. Adewole
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Penn Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA
| | - Mijail D. Serruya
- Department of Neurology, Jefferson University, Philadelphia, PA, USA
| | - James P. Harris
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
| | - Justin C. Burrell
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
| | - Dmitriy Petrov
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
| | - H. Isaac Chen
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
- Penn Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA
| | - John A. Wolf
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
| | - D. Kacy Cullen
- Center for Brain Injury and Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
- Penn Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, USA
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10
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Clements IP, Mukhatyar VJ, Srinivasan A, Bentley JT, Andreasen DS, Bellamkonda RV. Regenerative scaffold electrodes for peripheral nerve interfacing. IEEE Trans Neural Syst Rehabil Eng 2012; 21:554-66. [PMID: 23033438 DOI: 10.1109/tnsre.2012.2217352] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Advances in neural interfacing technology are required to enable natural, thought-driven control of a prosthetic limb. Here, we describe a regenerative electrode design in which a polymer-based thin-film electrode array is integrated within a thin-film sheet of aligned nanofibers, such that axons regenerating from a transected peripheral nerve are topographically guided across the electrode recording sites. Cultures of dorsal root ganglia were used to explore design parameters leading to cellular migration and neurite extension across the nanofiber/electrode array boundary. Regenerative scaffold electrodes (RSEs) were subsequently fabricated and implanted across rat tibial nerve gaps to evaluate device recording capabilities and influence on nerve regeneration. In 20 of these animals, regeneration was compared between a conventional nerve gap model and an amputation model. Characteristic shaping of regenerated nerve morphology around the embedded electrode array was observed in both groups, and regenerated axon profile counts were similar at the eight week end point. Implanted RSEs recorded evoked neural activity in all of these cases, and also in separate implantations lasting up to five months. These results demonstrate that nanofiber-based topographic cues within a regenerative electrode can influence nerve regeneration, to the potential benefit of a peripheral nerve interface suitable for limb amputees.
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Affiliation(s)
- Isaac P Clements
- Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 USA.
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11
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Abstract
One of the great challenges facing medicine is the repair of the damaged nervous system. Due to the limited capacity of the central (and to a lesser extent the peripheral) nervous systems to regenerate, damage such as spinal cord injury can often result in permanent paralysis. Researchers are attempting to overcome nerve injury by devising methods of sensing neural activity either in the brain or in the spinal cord or peripheral nervous system. This information can act as a control mechanism for either muscle stimulators (e.g. for restoring limb function) or providing function in some other way (such as controlling a cursor on a computer screen). Ideally, sensing devices are implanted into the body, directly accessing the nervous system. Whilst great advancements have been made in implantable neural stimulators, sensing of neural activity has proven to be a more difficult task. This chapter describes how microengineered probes allow construction of neuron-sized neural interfaces for enhanced recording in vivo.
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Affiliation(s)
- Karla D Bustamante Valles
- Orthopaedic & Rehabilitation Engineering Center, The Medical College of Wisconsin & Marquette University, Milwaukee, WI, USA
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12
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FitzGerald J, Lacour S, McMahon S, Fawcett J. Microchannel Electrodes for Recording and Stimulation:In VitroEvaluation. IEEE Trans Biomed Eng 2009; 56:1524-34. [DOI: 10.1109/tbme.2009.2013960] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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13
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Robust and real-time monitoring of nerve regeneration using implantable flexible microelectrode array. Biosens Bioelectron 2009; 24:1883-7. [DOI: 10.1016/j.bios.2008.09.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 09/22/2008] [Accepted: 09/23/2008] [Indexed: 11/23/2022]
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15
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Li J, Shi R. Fabrication of patterned multi-walled poly-l-lactic acid conduits for nerve regeneration. J Neurosci Methods 2007; 165:257-64. [PMID: 17644184 DOI: 10.1016/j.jneumeth.2007.06.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 06/03/2007] [Accepted: 06/04/2007] [Indexed: 10/23/2022]
Abstract
Topographical cues in the micron and nanoscale regime represent a powerful and effective method for controlling neuron and glial cell behavior. Previous studies have shown that contact guidance can facilitate axon pathfinding, accelerate neurite growth and induce glial cell alignment. In this paper, we exploit the concept of haptotaxis via implementation into three-dimensional neural based scaffolds. Polymeric poly-l-lactic acid (PLLA) conduits possessing multiple intralumenal walls and precise topography along the longitudinal axis were fabricated using solvent casting, physical imprinting and a rolling-fusing method. Measurements made on scanning electron micrographs show the conduits demonstrate a transparency factor (void to polymer ratio) of up to 87.9% and an increase in surface area of four to eight times over comparably sized hollow conduits. Intralumenal wall thickness was approximately 20 microm and physical parameters such as the number of lumens, conduit length and diameter were controllable. These results imply that the structures are conducive for cellular infiltration and proliferation. Although PLLA was used, the manufacturing techniques are highly flexible and are compatible with multiple polymer-solvent systems. Thus, the proposed conduits can be custom tailored to resorb in parallel with the healing process. Applications for these scaffolds include autograft substitutes for peripheral nerve transection or potential use in spinal cord related injuries.
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Affiliation(s)
- Jianming Li
- Weldon School of Biomedical Engineering, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA
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16
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Lago N, Udina E, Ramachandran A, Navarro X. Neurobiological assessment of regenerative electrodes for bidirectional interfacing injured peripheral nerves. IEEE Trans Biomed Eng 2007; 54:1129-37. [PMID: 17554832 DOI: 10.1109/tbme.2007.891168] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Regenerative electrodes are designed to interface regenerated axons from a sectioned peripheral nerve. Applicability of regenerative electrodes depends on biocompatibility, success of axonal regeneration, secondary nerve damage, and adequacy of interface electronics. Polyimide sieve electrodes with 281 holes were chronically implanted in the severed sciatic nerve of 30 rats. Regeneration was successful in all the animals, with increasing numbers of regenerated myelinated fibers from 2 to 6 mo. However, constrictive axonopathy affected a few cases from 6 to 12 mo. postimplantation. A second electrode design with 571 holes and 27 ring electrodes was developed. The number of regenerated axons increased thanks to the larger open area. Recordings were obtained from a low proportion of electrodes on the sieve in response to distal stimulation. Difficulties for recording impulses with regenerative electrodes include the small size of regenerated axons, changes in membrane excitability and in target reconnection.
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Affiliation(s)
- Natalia Lago
- Institute of Neurosciences, Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain.
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17
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Koch KP. Neural prostheses and biomedical microsystems in neurological rehabilitation. ACTA NEUROCHIRURGICA. SUPPLEMENT 2007; 97:427-34. [PMID: 17691406 DOI: 10.1007/978-3-211-33079-1_56] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Interfaces between electrodes and the neural system differ with respect to material and shape depending on their intended application and fabrication method. This chapter will review the different electrode designs regarding the technological implementation and fabrication process. Furthermore this book chapter will describe electrodes for interfacing the peripheral nerves like cuff, book or helix as well as electrodes for interfacing the cortex like needle arrays. The implantation method and mechanical interaction between the electrode and the nervous tissue were taken into consideration. To develop appropriate microtechnological assembling strategies that ensure proper interfacing between the tiny electrodes and microelectronics or connectors is one of the major challenges. The integration of electronics into the system helps to improve the reliability of detecting neural signals and reduces the size of the implants. Promising results with these novel electrodes will pave the road for future developments such as visual prosthetics or improved control of artificial limbs in paralyzed patients.
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Affiliation(s)
- K P Koch
- Fraunhofer Institut für Biomedizinische Technik, St. Ingbert, Germany.
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Ramachandran A, Schuettler M, Lago N, Doerge T, Koch KP, Navarro X, Hoffmann KP, Stieglitz T. Design, in vitro and in vivo assessment of a multi-channel sieve electrode with integrated multiplexer. J Neural Eng 2006; 3:114-24. [PMID: 16705267 DOI: 10.1088/1741-2560/3/2/005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This paper reports on the design, in vitro and in vivo investigation of a flexible, lightweight, polyimide based implantable sieve electrode with a hybrid assembly of multiplexers and polymer encapsulation. The integration of multiplexers enables us to connect a large number of electrodes on the sieve using few input connections. The implant assembly of the sieve electrode with the electronic circuitry was verified by impedance measurement. The 27 platinum electrodes of the sieve were coated with platinum black to reduce the electrode impedance. The impedance magnitude of the electrode sites on the sieve (geometric surface area 2,200 microm(2)) was |Z(f=1kHz)| = 5.7 kOmega. The sieve electrodes, encased in silicone, have been implanted in the transected sciatic nerve of rats. Initial experiments showed that axons regenerated through the holes of the sieve and reinnervated distal target organs. Nerve signals were recorded in preliminary tests after 3-7 months post-implantation.
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Affiliation(s)
- Anup Ramachandran
- Department of Medical Engineering and Neuroprosthetics, Fraunhofer-IBMT, Ensheimer Str. 48, 66386 St. Ingbert, Germany.
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Navarro X, Krueger TB, Lago N, Micera S, Stieglitz T, Dario P. A critical review of interfaces with the peripheral nervous system for the control of neuroprostheses and hybrid bionic systems. J Peripher Nerv Syst 2006; 10:229-58. [PMID: 16221284 DOI: 10.1111/j.1085-9489.2005.10303.x] [Citation(s) in RCA: 441] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Considerable scientific and technological efforts have been devoted to develop neuroprostheses and hybrid bionic systems that link the human nervous system with electronic or robotic prostheses, with the main aim of restoring motor and sensory functions in disabled patients. A number of neuroprostheses use interfaces with peripheral nerves or muscles for neuromuscular stimulation and signal recording. Herein, we provide a critical overview of the peripheral interfaces available and trace their use from research to clinical application in controlling artificial and robotic prostheses. The first section reviews the different types of non-invasive and invasive electrodes, which include surface and muscular electrodes that can record EMG signals from and stimulate the underlying or implanted muscles. Extraneural electrodes, such as cuff and epineurial electrodes, provide simultaneous interface with many axons in the nerve, whereas intrafascicular, penetrating, and regenerative electrodes may contact small groups of axons within a nerve fascicle. Biological, technological, and material science issues are also reviewed relative to the problems of electrode design and tissue injury. The last section reviews different strategies for the use of information recorded from peripheral interfaces and the current state of control neuroprostheses and hybrid bionic systems.
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Affiliation(s)
- Xavier Navarro
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain.
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Lee C, Kim Y, Shin H, Kim Y, Lee M. The measurement of compound neural action potential in sciatic nerve using microelectrode array. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2006; 2006:3002-3004. [PMID: 17947003 DOI: 10.1109/iembs.2006.260636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
As a method of observing regeneration of damaged nerves, research is being conducted on analyzing the electric signals of nerve fibers that are damaged and regenerating by implanting a microelectrode array between those nerves. Microelectrode arrays possess high impedance and a unique phase characteristic according to their structural features, thus it requires a phase linearity test and an impedance test to prevent neural signal distortion. Therefore, this paper analyzes the features of microelectrode array and designs a bioamplifier. We also measured signals from sciatic nerves in rats with microelectrode array.
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Affiliation(s)
- Chungkeun Lee
- Dept. of Electr. & Electron. Eng., Yonsei Univ., Seoul, Korea.
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Lee C, Kim Y, Shin H, Kim Y, Lee M. The measurement of compound neural action potential in sciatic nerve using microelectrode array. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2006; Suppl:6743-6746. [PMID: 17959501 DOI: 10.1109/iembs.2006.260936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
As a method of observing regeneration of damaged nerves, research is being conducted on analyzing the electric signals of nerve fibers that are damaged and regenerating by implanting a microelectrode array between those nerves. Microelectrode arrays possess high impedance and a unique phase characteristic according to their structural features,thus it requires a phase linearity test and an impedance test to prevent neural signal distortion.Therefore, this paper analyzes the features of microelectrode array and designs a bioamplifier. We also measured signals from sciatic nerves in rats with microelectrode array.
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Affiliation(s)
- Chungkeun Lee
- Electrical & Electronics Engineering Department, University of Yonsei, Seoul, Korea.
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Dhillon GS, Krüger TB, Sandhu JS, Horch KW. Effects of Short-Term Training on Sensory and Motor Function in Severed Nerves of Long-Term Human Amputees. J Neurophysiol 2005; 93:2625-33. [PMID: 15846000 DOI: 10.1152/jn.00937.2004] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Much has been studied and written about plastic changes in the CNS of humans triggered by events such as limb amputation. However, little is known about the extent to which the original pathways retain residual function after peripheral amputation. Our earlier, acute study on long-term amputees indicated that central pathways associated with amputated peripheral nerves retain at least some sensory and motor function. The purpose of the present study was to determine if these functional connections would be strengthened or improved with experience and training over several days time. To do this, electrodes were implanted within fascicles of severed nerves of long-term human amputees to evaluate the changes in electrically evoked sensations and volitional motor neuron activity associated with attempted phantom limb movements. Nerve stimulation consistently resulted in discrete, unitary, graded sensations of touch/pressure and joint-position sense. There was no significant change in the values of stimulation parameters required to produce these sensations over time. Similarly, while the amputees were able to improve volitional control of motor neuron activity, the rate and pattern of change was similar to that seen with practice in normal individuals on motor tasks. We conclude that the central plasticity seen after amputation is most likely primarily due to unmasking, rather than replacement, of existing synaptic connections. These results also have implications for neural control of prosthetic limbs.
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Affiliation(s)
- G S Dhillon
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA.
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