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Vatsyayan R, Dayeh SA. A universal model of electrochemical safety limits in vivo for electrophysiological stimulation. Front Neurosci 2022; 16:972252. [PMID: 36277998 PMCID: PMC9582612 DOI: 10.3389/fnins.2022.972252] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 09/12/2022] [Indexed: 11/26/2022] Open
Abstract
Electrophysiological stimulation has been widely adopted for clinical diagnostic and therapeutic treatments for modulation of neuronal activity. Safety is a primary concern in an interventional design leveraging the effects of electrical charge injection into tissue in the proximity of target neurons. While modalities of tissue damage during stimulation have been extensively investigated for specific electrode geometries and stimulation paradigms, a comprehensive model that can predict the electrochemical safety limits in vivo doesn’t yet exist. Here we develop a model that accounts for the electrode geometry, inter-electrode separation, material, and stimulation paradigm in predicting safe current injection limits. We performed a parametric investigation of the stimulation limits in both benchtop and in vivo setups for flexible microelectrode arrays with low impedance, high geometric surface area platinum nanorods and PEDOT:PSS, and higher impedance, planar platinum contacts. We benchmark our findings against standard clinical electrocorticography and depth electrodes. Using four, three and two contact electrochemical impedance measurements and comprehensive circuit models derived from these measurements, we developed a more accurate, clinically relevant and predictive model for the electrochemical interface potential. For each electrode configuration, we experimentally determined the geometric correction factors that dictate geometry-enforced current spreading effects. We also determined the electrolysis window from cyclic-voltammetry measurements which allowed us to calculate stimulation current safety limits from voltage transient measurements. From parametric benchtop electrochemical measurements and analyses for different electrode types, we created a predictive equation for the cathodal excitation measured at the electrode interface as a function of the electrode dimensions, geometric factor, material and stimulation paradigm. We validated the accuracy of our equation in vivo and compared the experimentally determined safety limits to clinically used stimulation protocols. Our new model overcomes the design limitations of Shannon’s equation and applies to macro- and micro-electrodes at different density or separation of contacts, captures the breakdown of charge-density based approaches at long stimulation pulse widths, and invokes appropriate power exponents to current, pulse width, and material/electrode-dependent impedance.
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2
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Varkevisser F, Costa T, Serdijn WA. Energy efficiency of pulse shaping in electrical stimulation: the interdependence of biophysical effects and circuit design losses. Biomed Phys Eng Express 2022; 8. [PMID: 36001921 DOI: 10.1088/2057-1976/ac8c47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/24/2022] [Indexed: 11/12/2022]
Abstract
Power efficiency in electrical stimulator circuits is crucial for developing large-scale multichannel applications like bidirectional brain-computer interfaces and neuroprosthetic devices. Many state-of-the-art papers have suggested that some non-rectangular pulse shapes are more energy-efficient for exciting neural excitation than the conventional rectangular shape. However, additional losses in the stimulator circuit, which arise from employing such pulses, were not considered. In this work, we analyze the total energy efficiency of a stimulation system featuring non-rectangular stimuli, taking into account the losses in the stimulator circuit. To this end, activation current thresholds for different pulse shapes and durations in cortical neurons are modeled, and the energy required to generate the pulses from a constant voltage supply is calculated. The proposed calculation reveals an energy increase of 14-51% for non-rectangular pulses compared to the conventional rectangular stimuli, instead of the decrease claimed in previous literature. This result indicates that a rectangular stimulation pulse is more power-efficient than the tested alternative shapes in large-scale multichannel electrical stimulation systems.
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Affiliation(s)
- Francesc Varkevisser
- Microelectronics, section Bioelectronics, Delft University of Technology EEMCS, Mekelweg 4, Delft, Zuid-Holland, 2628CD, NETHERLANDS
| | - Tiago Costa
- Microelectronics, section Bioelectronics, Delft University of Technology EEMCS, Mekelweg 4, Delft, Zuid-Holland, 2628CD, NETHERLANDS
| | - Wouter A Serdijn
- Microelectronics, section Bioelectronics, Delft University of Technology EEMCS, Mekelweg 4, Delft, Zuid-Holland, 2628CD, NETHERLANDS
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3
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Datta-Chaudhuri T. Closed-loop neuromodulation will increase the utility of mouse models in Bioelectronic Medicine. Bioelectron Med 2021; 7:10. [PMID: 34193309 PMCID: PMC8244222 DOI: 10.1186/s42234-021-00071-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/01/2021] [Indexed: 01/16/2023] Open
Abstract
Mouse models have been of tremendous benefit to medical science for the better part of a century, yet bioelectronic medicine research using mice has been limited to mostly acute studies because of a lack of tools for chronic stimulation and sensing. A wireless neuromodulation platform small enough for implantation in mice will significantly increase the utility of mouse models in bioelectronic medicine. This perspective examines the necessary functionality of such a system and the technical challenges needed to be overcome for its development. Recent progress is examined and the outlook for the future of implantable devices for mice is discussed.
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Affiliation(s)
- Timir Datta-Chaudhuri
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell Health, 350 Community Drive, Manhasset, NY, 11030, USA. .,Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 500 Hofstra University, Hempstead, NY, 11549, USA.
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4
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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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5
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Vatsyayan R, Cleary D, Martin JR, Halgren E, Dayeh SA. Electrochemical safety limits for clinical stimulation investigated using depth and strip electrodes in the pig brain. J Neural Eng 2021; 18. [PMID: 34015769 DOI: 10.1088/1741-2552/ac038b] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 05/20/2021] [Indexed: 11/12/2022]
Abstract
Objective. Diagnostic and therapeutic electrical stimulation are increasingly utilized with the rise of neuromodulation devices. However, systematic investigations that depict the practical clinical stimulation paradigms (bipolar, two-electrode configuration) to determine the safety limits are currently lacking. Further, safe charge densities that were classically determined from conical sharp electrodes are generalized for cylindrical (depth) and flat (surface grid) electrodes completely ignoring geometric factors that govern current spreading and trajectories in tissue.Approach. This work reports the first investigations comparing stimulation limits for clinically used electrodes in two mediums: in benchtop experiments in saline andin vivoin a single acute experiment in the pig brain. We experimentally determine the geometric factors, the water electrolysis windows, and the current safety limits from voltage transients, for the sEEG, depth and surface strip electrodes in both mediums. Using four-electrode and three-electrode configuration measurements and comprehensive circuit models that accurately depict our measurements, we delineate the various elements of the stimulation medium, including the tissue-electrode interface impedance spectra, the medium impedance and the bias-dependent change in the interface impedance as a function of stimulation parameters.Main results. The results of our systematics studies suggest that safe currents in clinical bipolar stimulation determinedin vivocan be as much as 24 times smaller than those determined from benchtop experiments (for depth electrodes at a 1 ms pulse duration). Our detailed circuit modeling attributes this drastic difference in safe limits to the greatly dissimilar electrode/tissue and electrode/saline impedances.Significance. We established the electrochemical safety limits for commonly used clinical electrodesin vivoand revealed by detailied electrochemical modeling how they differ from benchtop evaluation. We argue that electrochemical limits and currents are unique for each electrode, should be measuredin vivoaccording to the protocols established in this work, and should be accounted for while setting the stimulation parameters for clinical applications including for chronic applications.
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Affiliation(s)
- Ritwik Vatsyayan
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California, San Diego, CA 92093, United States of America
| | - Daniel Cleary
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California, San Diego, CA 92093, United States of America.,Department of Neurological Surgery, University of California, San Diego, CA 92097, United States of America
| | - Joel R Martin
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California, San Diego, CA 92093, United States of America.,Department of Neurological Surgery, University of California, San Diego, CA 92097, United States of America
| | - Eric Halgren
- Department of Radiology, University of California, San Diego, CA 92097, United States of America
| | - Shadi A Dayeh
- Integrated Electronics and Biointerfaces Laboratory, Department of Electrical and Computer Engineering, University of California, San Diego, CA 92093, United States of America
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6
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Zheng XS, Tan C, Castagnola E, Cui XT. Electrode Materials for Chronic Electrical Microstimulation. Adv Healthc Mater 2021; 10:e2100119. [PMID: 34029008 PMCID: PMC8257249 DOI: 10.1002/adhm.202100119] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/20/2021] [Indexed: 02/06/2023]
Abstract
Electrical microstimulation has enabled partial restoration of vision, hearing, movement, somatosensation, as well as improving organ functions by electrically modulating neural activities. However, chronic microstimulation is faced with numerous challenges. The implantation of an electrode array into the neural tissue triggers an inflammatory response, which can be exacerbated by the delivery of electrical currents. Meanwhile, prolonged stimulation may lead to electrode material degradation., which can be accelerated by the hostile inflammatory environment. Both material degradation and adverse tissue reactions can compromise stimulation performance over time. For stable chronic electrical stimulation, an ideal microelectrode must present 1) high charge injection limit, to efficiently deliver charge without exceeding safety limits for both tissue and electrodes, 2) small size, to gain high spatial selectivity, 3) excellent biocompatibility that ensures tissue health immediately next to the device, and 4) stable in vivo electrochemical properties over the application period. In this review, the challenges in chronic microstimulation are described in detail. To aid material scientists interested in neural stimulation research, the in vitro and in vivo testing methods are introduced for assessing stimulation functionality and longevity and a detailed overview of recent advances in electrode material research and device fabrication for improving chronic microstimulation performance is provided.
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Affiliation(s)
- Xin Sally Zheng
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Chao Tan
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave. Pittsburgh, Pittsburgh, PA, 15213, USA
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7
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Mughrabi IT, Hickman J, Jayaprakash N, Thompson D, Ahmed U, Papadoyannis ES, Chang YC, Abbas A, Datta-Chaudhuri T, Chang EH, Zanos TP, Lee SC, Froemke RC, Tracey KJ, Welle C, Al-Abed Y, Zanos S. Development and characterization of a chronic implant mouse model for vagus nerve stimulation. eLife 2021; 10:e61270. [PMID: 33821789 PMCID: PMC8051950 DOI: 10.7554/elife.61270] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 04/02/2021] [Indexed: 12/17/2022] Open
Abstract
Vagus nerve stimulation (VNS) suppresses inflammation and autoimmune diseases in preclinical and clinical studies. The underlying molecular, neurological, and anatomical mechanisms have been well characterized using acute electrophysiological stimulation of the vagus. However, there are several unanswered mechanistic questions about the effects of chronic VNS, which require solving numerous technical challenges for a long-term interface with the vagus in mice. Here, we describe a scalable model for long-term VNS in mice developed and validated in four research laboratories. We observed significant heart rate responses for at least 4 weeks in 60-90% of animals. Device implantation did not impair vagus-mediated reflexes. VNS using this implant significantly suppressed TNF levels in endotoxemia. Histological examination of implanted nerves revealed fibrotic encapsulation without axonal pathology. This model may be useful to study the physiology of the vagus and provides a tool to systematically investigate long-term VNS as therapy for chronic diseases modeled in mice.
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Affiliation(s)
- Ibrahim T Mughrabi
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Jordan Hickman
- Departments of Neurosurgery, University of Colorado Anschutz Medical CampusAuroraUnited States
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Naveen Jayaprakash
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Dane Thompson
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
- The Elmezzi Graduate School of Molecular MedicineManhassetUnited States
| | - Umair Ahmed
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Eleni S Papadoyannis
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York UniversityNew YorkUnited States
- Department of Neuroscience and Physiology, Neuroscience Institute, Center for Neural Science, New York University School of Medicine, New York UniversityNew YorkUnited States
- Department of Otolaryngology, New York University School of Medicine, New York UniversityNew YorkUnited States
- Howard Hughes Medical Institute Faculty Scholar, New York University School of Medicine, New York UniversityNew YorkUnited States
| | - Yao-Chuan Chang
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Adam Abbas
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Timir Datta-Chaudhuri
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Eric H Chang
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Theodoros P Zanos
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Sunhee C Lee
- Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Robert C Froemke
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York UniversityNew YorkUnited States
- Department of Neuroscience and Physiology, Neuroscience Institute, Center for Neural Science, New York University School of Medicine, New York UniversityNew YorkUnited States
- Department of Otolaryngology, New York University School of Medicine, New York UniversityNew YorkUnited States
- Howard Hughes Medical Institute Faculty Scholar, New York University School of Medicine, New York UniversityNew YorkUnited States
| | - Kevin J Tracey
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Cristin Welle
- Departments of Neurosurgery, University of Colorado Anschutz Medical CampusAuroraUnited States
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Yousef Al-Abed
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
| | - Stavros Zanos
- Institute of Bioelectronic Medicine, The Feinstein Institutes for Medical Research, Northwell HealthManhassetUnited States
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8
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Millevolte AXT, Dingle AM, Ness JP, Novello J, Zeng W, Lu Y, Minor RL, Nemke B, Markel MD, Suminski AJ, Williams JC, Poore SO. Improving the Selectivity of an Osseointegrated Neural Interface: Proof of Concept For Housing Sieve Electrode Arrays in the Medullary Canal of Long Bones. Front Neurosci 2021; 15:613844. [PMID: 33790731 PMCID: PMC8006940 DOI: 10.3389/fnins.2021.613844] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 02/16/2021] [Indexed: 01/15/2023] Open
Abstract
Sieve electrodes stand poised to deliver the selectivity required for driving advanced prosthetics but are considered inherently invasive and lack the stability required for a chronic solution. This proof of concept experiment investigates the potential for the housing and engagement of a sieve electrode within the medullary canal as part of an osseointegrated neural interface (ONI) for greater selectivity toward improving prosthetic control. The working hypotheses are that (A) the addition of a sieve interface to a cuff electrode housed within the medullary canal of the femur as part of an ONI would be capable of measuring efferent and afferent compound nerve action potentials (CNAPs) through a greater number of channels; (B) that signaling improves over time; and (C) that stimulation at this interface generates measurable cortical somatosensory evoked potentials through a greater number of channels. The modified ONI was tested in a rabbit (n = 1) amputation model over 12 weeks, comparing the sieve component to the cuff, and subsequently compared to historical data. Efferent CNAPs were successfully recorded from the sieve demonstrating physiological improvements in CNAPs between weeks 3 and 5, and somatosensory cortical responses recorded at 12 weeks postoperatively. This demonstrates that sieve electrodes can be housed and function within the medullary canal, demonstrated by improved nerve engagement and distinct cortical sensory feedback. This data presents the conceptual framework for housing more sophisticated sieve electrodes in bone as part of an ONI for improving selectivity with percutaneous connectivity toward improved prosthetic control.
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Affiliation(s)
- Augusto X T Millevolte
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin - Madison, Madison, WI, United States.,Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States
| | - Aaron M Dingle
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin - Madison, Madison, WI, United States
| | - Jared P Ness
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States
| | - Joseph Novello
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States
| | - Weifeng Zeng
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin - Madison, Madison, WI, United States
| | - Yan Lu
- Department of Medical Sciences, University of Wisconsin - Madison, Madison, WI, United States
| | - Rashea L Minor
- Department of Medical Sciences, University of Wisconsin - Madison, Madison, WI, United States
| | - Brett Nemke
- Department of Medical Sciences, University of Wisconsin - Madison, Madison, WI, United States
| | - Mark D Markel
- Department of Medical Sciences, University of Wisconsin - Madison, Madison, WI, United States
| | - Aaron J Suminski
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States.,Department of Medical Sciences, University of Wisconsin - Madison, Madison, WI, United States.,Department of Neurological Surgery, University of Wisconsin - Madison, Madison, WI, United States
| | - Justin C Williams
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States.,Department of Neurological Surgery, University of Wisconsin - Madison, Madison, WI, United States
| | - Samuel O Poore
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin - Madison, Madison, WI, United States.,Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States
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Sahasrabuddhe K, Khan AA, Singh AP, Stern TM, Ng Y, Tadić A, Orel P, LaReau C, Pouzzner D, Nishimura K, Boergens KM, Shivakumar S, Hopper MS, Kerr B, Hanna MES, Edgington RJ, McNamara I, Fell D, Gao P, Babaie-Fishani A, Veijalainen S, Klekachev AV, Stuckey AM, Luyssaert B, Kozai TDY, Xie C, Gilja V, Dierickx B, Kong Y, Straka M, Sohal HS, Angle MR. The Argo: a high channel count recording system for neural recording in vivo. J Neural Eng 2021; 18:015002. [PMID: 33624614 PMCID: PMC8607496 DOI: 10.1088/1741-2552/abd0ce] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Decoding neural activity has been limited by the lack of tools available to record from large numbers of neurons across multiple cortical regions simultaneously with high temporal fidelity. To this end, we developed the Argo system to record cortical neural activity at high data rates. APPROACH Here we demonstrate a massively parallel neural recording system based on platinum-iridium microwire electrode arrays bonded to a CMOS voltage amplifier array. The Argo system is the highest channel count in vivo neural recording system, supporting simultaneous recording from 65 536 channels, sampled at 32 kHz and 12-bit resolution. This system was designed for cortical recordings, compatible with both penetrating and surface microelectrodes. MAIN RESULTS We validated this system through initial bench testing to determine specific gain and noise characteristics of bonded microwires, followed by in-vivo experiments in both rat and sheep cortex. We recorded spiking activity from 791 neurons in rats and surface local field potential activity from over 30 000 channels in sheep. SIGNIFICANCE These are the largest channel count microwire-based recordings in both rat and sheep. While currently adapted for head-fixed recording, the microwire-CMOS architecture is well suited for clinical translation. Thus, this demonstration helps pave the way for a future high data rate intracortical implant.
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Affiliation(s)
| | - Aamir A Khan
- Paradromics, Inc, Austin, TX, United States of America
| | | | - Tyler M Stern
- Paradromics, Inc, Austin, TX, United States of America
| | - Yeena Ng
- Paradromics, Inc, Austin, TX, United States of America
| | | | - Peter Orel
- Paradromics, Inc, Austin, TX, United States of America
| | - Chris LaReau
- Paradromics, Inc, Austin, TX, United States of America
| | | | | | | | | | | | - Bryan Kerr
- Paradromics, Inc, Austin, TX, United States of America
| | | | | | | | - Devin Fell
- Paradromics, Inc, Austin, TX, United States of America
| | - Peng Gao
- Caeleste CVBA, Mechelen, Belgium
| | | | | | | | | | | | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States of America
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, United States of America
- Department of Bioengineering, Rice University, Houston, TX, United States of America
- NeuroEngineering Initiative, Rice University, Houston, TX, United States of America
| | - Vikash Gilja
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States of America
| | | | - Yifan Kong
- Paradromics, Inc, Austin, TX, United States of America
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10
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Dingle AM, Ness JP, Novello J, Millevolte AXT, Zeng W, Sanchez R, Nemke B, Lu Y, Suminski AJ, Markel MD, Williams JC, Poore SO. Experimental Basis for Creating an Osseointegrated Neural Interface for Prosthetic Control: A Pilot Study in Rabbits. Mil Med 2020; 185:462-469. [PMID: 32074371 DOI: 10.1093/milmed/usz246] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
INTRODUCTION While debate persists over how to best prevent or treat amputation neuromas, the more pressing question of how to best marry residual nerves to state-of-the-art robotic prostheses for naturalistic control of a replacement limb has come to the fore. One potential solution involves the transposition of terminal nerve ends into the medullary canal of long bones, creating the neural interface within the bone. Nerve transposition into bone is a long-practiced, clinically relevant treatment for painful neuromas. Despite neuropathic pain relief, the physiological capacity of transposed nerves to conduct motor and sensory signals required for prosthesis control remains unknown. This pilot study addresses the hypotheses that (1) bone provides stability to transposed nerves and (2) nerves transposed into bone remain physiologically active, as they relate to the creation of an osseointegrated neural interface. METHODS New Zealand white rabbits received transfemoral amputation, with the sciatic nerve transposed into the femur. RESULTS Morphological examination demonstrates that nerves remain stable within the medullary canal, while compound nerve action potentials evoked by electrical stimulation of the residual nerve within the bone could be achieved at 12 weeks (p < 0.0005). CONCLUSION Transposed nerves retain a degree of physiological function suitable for creating an osseointegrated neural interface.
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Affiliation(s)
- Aaron M Dingle
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Jared P Ness
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Joseph Novello
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Augusto X T Millevolte
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Weifeng Zeng
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Ruston Sanchez
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Brett Nemke
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Yan Lu
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Aaron J Suminski
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792.,Department of Neurological Surgery, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Mark D Markel
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Justin C Williams
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
| | - Samuel O Poore
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792.,Department of Biomedical Engineering, College of Engineering, University of Wisconsin-Madison, 600 Highland Avenue, Madison WI 53792
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11
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Dunlap CF, Colachis SC, Meyers EC, Bockbrader MA, Friedenberg DA. Classifying Intracortical Brain-Machine Interface Signal Disruptions Based on System Performance and Applicable Compensatory Strategies: A Review. Front Neurorobot 2020; 14:558987. [PMID: 33162885 PMCID: PMC7581895 DOI: 10.3389/fnbot.2020.558987] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 09/09/2020] [Indexed: 12/18/2022] Open
Abstract
Brain-machine interfaces (BMIs) record and translate neural activity into a control signal for assistive or other devices. Intracortical microelectrode arrays (MEAs) enable high degree-of-freedom BMI control for complex tasks by providing fine-resolution neural recording. However, chronically implanted MEAs are subject to a dynamic in vivo environment where transient or systematic disruptions can interfere with neural recording and degrade BMI performance. Typically, neural implant failure modes have been categorized as biological, material, or mechanical. While this categorization provides insight into a disruption's causal etiology, it is less helpful for understanding degree of impact on BMI function or possible strategies for compensation. Therefore, we propose a complementary classification framework for intracortical recording disruptions that is based on duration of impact on BMI performance and requirement for and responsiveness to interventions: (1) Transient disruptions interfere with recordings on the time scale of minutes to hours and can resolve spontaneously; (2) Reversible disruptions cause persistent interference in recordings but the root cause can be remedied by an appropriate intervention; (3) Irreversible compensable disruptions cause persistent or progressive decline in signal quality, but their effects on BMI performance can be mitigated algorithmically; and (4) Irreversible non-compensable disruptions cause permanent signal loss that is not amenable to remediation or compensation. This conceptualization of intracortical BMI disruption types is useful for highlighting specific areas for potential hardware improvements and also identifying opportunities for algorithmic interventions. We review recording disruptions that have been reported for MEAs and demonstrate how biological, material, and mechanical mechanisms of disruption can be further categorized according to their impact on signal characteristics. Then we discuss potential compensatory protocols for each of the proposed disruption classes. Specifically, transient disruptions may be minimized by using robust neural decoder features, data augmentation methods, adaptive machine learning models, and specialized signal referencing techniques. Statistical Process Control methods can identify reparable disruptions for rapid intervention. In-vivo diagnostics such as impedance spectroscopy can inform neural feature selection and decoding models to compensate for irreversible disruptions. Additional compensatory strategies for irreversible disruptions include information salvage techniques, data augmentation during decoder training, and adaptive decoding methods to down-weight damaged channels.
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Affiliation(s)
- Collin F. Dunlap
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH, United States
| | - Samuel C. Colachis
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH, United States
| | - Eric C. Meyers
- Medical Devices and Neuromodulation, Battelle Memorial Institute, Columbus, OH, United States
| | - Marcia A. Bockbrader
- Department of Physical Medicine and Rehabilitation, The Ohio State University, Columbus, OH, United States
| | - David A. Friedenberg
- Advanced Analytics and Health Research, Battelle Memorial Institute, Columbus, OH, United States
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12
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Falcone JD, Liu T, Goldman L, David D P, Rieth L, Bouton CE, Straka M, Sohal HS. A novel microwire interface for small diameter peripheral nerves in a chronic, awake murine model. J Neural Eng 2020; 17:046003. [DOI: 10.1088/1741-2552/ab9b6d] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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13
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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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Vo J, Chang TC, Shea KI, Myers M, Arbabian A, Vasudevan S. Assessment of miniaturized ultrasound-powered implants: an in vivo study. J Neural Eng 2020; 17:016072. [DOI: 10.1088/1741-2552/ab6fc2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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15
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Zheng XS, Griffith AY, Chang E, Looker MJ, Fisher LE, Clapsaddle B, Cui XT. Evaluation of a conducting elastomeric composite material for intramuscular electrode application. Acta Biomater 2020; 103:81-91. [PMID: 31863910 DOI: 10.1016/j.actbio.2019.12.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/25/2019] [Accepted: 12/10/2019] [Indexed: 01/14/2023]
Abstract
Electrical stimulation of the muscle has been proven efficacious in preventing atrophy and/or reanimating paralyzed muscles. Intramuscular electrodes made from metals have significantly higher Young's Moduli than the muscle tissues, which has the potential to cause chronic inflammation and decrease device performance. Here, we present an intramuscular electrode made from an elastomeric conducting polymer composite consisting of PEDOT-PEG copolymer, silicone and carbon nanotubes (CNT) with fluorosilicone insulation. The electrode wire has a Young's modulus of 804 (±99) kPa, which better mimics the muscle tissue modulus than conventional stainless steel (SS) electrodes. Additionally, the non-metallic composition enables metal-artifact free CT and MR imaging. These soft wire (SW) electrodes present comparable electrical impedance to SS electrodes of similar geometric surface area, activate muscle at a lower threshold, and maintain stable electrical properties in vivo up to 4 weeks. Histologically, the SW electrodes elicited significantly less fibrotic encapsulation and less IBA-1 positive macrophage accumulation than the SS electrodes at one and three months. Further phenotyping the macrophages with the iNOS (pro-inflammatory) and ARG-1 (pro-healing) markers revealed significantly less presence of pro-inflammatory macrophage around SW implants at one month. By three months, there was a significant increase in pro-healing macrophages (ARG-1) around the SW implants but not around the SS implants. Furthermore, a larger number of AchR clusters closer to SW implants were found at both time points compared to SS implants. These results suggest that a softer implant encourages a more intimate and healthier electrode-tissue interface. STATEMENT OF SIGNIFICANCE: Intramuscular electrodes made from metals have significantly higher Young's Moduli than the muscle tissues, which has the potential to cause chronic inflammation and decrease device performance. Here, we present an intramuscular electrode made from an elastomeric conducting polymer composite consisting of PEDOT-PEG copolymer, silicone and carbon nanotubes with fluorosilicone insulation. This elastomeric composite results in an electrode wire with a Young's modulus mimicking that of the muscle tissue, which elicits significantly less foreign body response compared to stainless steel wires. The lack of metal in this composite also enables metal-artifact free MRI and CT imaging.
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Affiliation(s)
- X Sally Zheng
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - Azante Y Griffith
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, United States
| | - Emily Chang
- TDA Research Inc., Wheat Ridge, CO 80033, United States
| | | | - Lee E Fisher
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, United States; Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA 15213, United States; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States
| | | | - X Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, United States; Center for Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
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16
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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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Dingle AM, Ness JP, Novello J, Israel JS, Sanchez R, Millevolte AXT, Brodnick S, Krugner-Higby L, Nemke B, Lu Y, Suminski AJ, Markel MD, Williams JC, Poore SO. Methodology for creating a chronic osseointegrated neural interface for prosthetic control in rabbits. J Neurosci Methods 2019; 331:108504. [PMID: 31711884 DOI: 10.1016/j.jneumeth.2019.108504] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 11/04/2019] [Accepted: 11/07/2019] [Indexed: 01/08/2023]
Abstract
BACKGROUND Chronic stability and high degrees of selectivity are both essential but somewhat juxtaposed components for creating an implantable bi-directional PNI capable of controlling of a prosthetic limb. While the more invasive implantable electrode arrays provide greater specificity, they are less stable over time due to compliance mismatch with the dynamic soft tissue environment in which the interface is created. NEW METHOD This paper takes the surgical approach of transposing nerves into bone to create neural interface within the medullary canal of long bones, an osseointegrated neural interface, to provide greater stability for implantable electrodes. In this context, we describe the surgical model for transfemoral amputation with transposition of the sciatic nerve into the medullary canal in rabbits. We investigate the capacity to create a neural interface within the medullary canal histolomorphologically. In a separate proof of concept experiment, we quantify the chronic physiological capacity of transposed nerves to conduct compound nerve action potentials evoked via an Osseointegrated Neural Interface. COMPARISON WITH EXISTING METHOD(S) The rabbit serves as an important animal model for both amputation neuroma and osseointegration research, but is underutilized for the exploration neural interfacing in an amputation setting. RESULTS Our findings demonstrate that transposed nerves remain stable over 12 weeks. Creating a neural interface within the medullary canal is possible and does not impede nerve regeneration or physiological capacity. CONCLUSIONS This article represents the first evidence that an Osseointegrated Neural Interface can be surgically created, capable of chronic stimulation/recording from amputated nerves required for future prosthetic control.
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Affiliation(s)
- Aaron M Dingle
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin - Madison, Madison, WI, United States
| | - Jared P Ness
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States
| | - Joseph Novello
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States
| | - Jacqueline S Israel
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin - Madison, Madison, WI, United States
| | - Ruston Sanchez
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin - Madison, Madison, WI, United States
| | - Augusto X T Millevolte
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin - Madison, Madison, WI, United States
| | - Sarah Brodnick
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States
| | - Lisa Krugner-Higby
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin - Madison, Madison, WI, United States
| | - Brett Nemke
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin - Madison, Madison, WI, United States
| | - Yan Lu
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin - Madison, Madison, WI, United States
| | - Aaron J Suminski
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States; Department of Neurological Surgery, University of Wisconsin - Madison, Madison, WI, United States
| | - Mark D Markel
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin - Madison, Madison, WI, United States
| | - Justin C Williams
- Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States
| | - Samuel O Poore
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin - Madison, Madison, WI, United States; Department of Biomedical Engineering, College of Engineering, University of Wisconsin - Madison, Madison, WI, United States.
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18
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Pancrazio JJ, Cogan SF. Editorial for the Special Issue on Neural Electrodes: Design and Applications. MICROMACHINES 2019; 10:mi10070466. [PMID: 31336980 PMCID: PMC6680485 DOI: 10.3390/mi10070466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 07/09/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, BSB 13.633, Richardson, TX 75080, USA.
| | - Stuart F Cogan
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, BSB 13.633, Richardson, TX 75080, USA.
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Yaghouby F, Shafer B, Vasudevan S. A rodent model for long-term vagus nerve stimulation experiments. ACTA ACUST UNITED AC 2019. [DOI: 10.2217/bem-2019-0016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aim: Investigations into the benefits of vagus nerve stimulation (VNS) using rodents have led to promising findings for treating clinical disorders. However, the majority of research has been limited to acute timelines. We developed a rodent model for longitudinal assessment of VNS and validated it with a long-term experiment incorporating continuous physiological monitoring. While the primary aim was not to investigate the effects of VNS on the cardiovascular system, we analyzed cardiovascular parameters to demonstrate the model's capabilities in a long-term stimulation-and-recording setup. Materials & methods: Rats were implanted with a cuff electrode around the cervical vagus nerve and electrocardiogram monitoring devices were implanted in the peritoneal cavity. We also designed a connector mount for seamless access to the cuff electrode for VNS in awake-behaving rats. Results & conclusion: Results signified easy-to-interface VNS system, electrode robustness and discernible physiological signals in a long-term setup. Analysis of the cardiovascular parameters revealed some transient effects during VNS. Our proposed model enables long-term VNS experiments along with physiological monitoring in unanesthetized rats.
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Affiliation(s)
- Farid Yaghouby
- US Food & Drug Administration, Center for Devices & Radiological Health (CDRH), Office of Science & Engineering Laboratory (OSEL), Division of Biomedical Physics (DBP), Silver Spring, MD 20993, USA
| | - Benjamin Shafer
- US Food & Drug Administration, Center for Devices & Radiological Health (CDRH), Office of Science & Engineering Laboratory (OSEL), Division of Biomedical Physics (DBP), Silver Spring, MD 20993, USA
| | - Srikanth Vasudevan
- US Food & Drug Administration, Center for Devices & Radiological Health (CDRH), Office of Science & Engineering Laboratory (OSEL), Division of Biomedical Physics (DBP), Silver Spring, MD 20993, USA
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Ahmad HMN, Si B, Dutta G, Csoros JR, Seitz WR, Song E. NON-ENZYMATIC ELECTROCHEMICAL DETECTION OF GLUTAMATE USING TEMPLATED POLYMER-BASED TARGET RECEPTORS. INTERNATIONAL SOLID-STATE SENSORS, ACTUATORS AND MICROSYSTEMS CONFERENCE : [PROCEEDINGS]. INTERNATIONAL CONFERENCE ON SOLID-STATE SENSORS, ACTUATORS, AND MICROSYSTEMS 2019; 2019:613-616. [PMID: 32719735 PMCID: PMC7384742 DOI: 10.1109/transducers.2019.8808688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We present a novel electrochemical biosensing platform for the detection of neurotransmitter glutamate using templated polymer-based target receptors. Our sensing approach demonstrates, for the first time, a non-enzymatic approach without the need of glutamate oxidase, leading to a more specific and rapid response. The proposed detection principle is based on the following two claims: (1) our templated polymer-based receptor results in specific molecular recognition of the target glutamate and, (2) upon target binding, the polymer undergoes a conformation change which can then be measured via electrochemical techniques. This sensing platform has the potential to provide direct monitoring of a variety of non-electroactive species and to eliminate the incorporation of enzymes thereby providing a simpler and more robust alternative to enzyme-based sensors.
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Affiliation(s)
- Habib M N Ahmad
- Department of Electrical and Computer Engineering, University of New Hampshire, USA
| | - Bo Si
- Department of Electrical and Computer Engineering, University of New Hampshire, USA
| | - Gaurab Dutta
- Department of Electrical and Computer Engineering, University of New Hampshire, USA
| | - John R Csoros
- Department of Chemistry, University of New Hampshire, USA
| | | | - Edward Song
- Department of Electrical and Computer Engineering, University of New Hampshire, USA
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