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Welle CG, Gao YR, Ye M, Lozzi A, Boretsky A, Abliz E, Hammer DX. Longitudinal neural and vascular structural dynamics produced by chronic microelectrode implantation. Biomaterials 2020; 238:119831. [PMID: 32045783 DOI: 10.1016/j.biomaterials.2020.119831] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 01/06/2020] [Accepted: 01/25/2020] [Indexed: 12/16/2022]
Abstract
Implanted microelectrode arrays sense local neuronal activity, signals which are used as control commands for brain computer interface (BCI) technology. Patients with tetraplegia have used BCI technology to achieve an extraordinary degree of interaction with their local environment. However, current microelectrode arrays for BCIs lose the ability to record high-quality neural signals in the months-to-years following implantation. Very little is known regarding the dynamic response of neurons and vasculature in the months following electrode array implantation, but loss of structural integrity near the electrode may contribute to the degradation of recording signals. Here, we use in-vivo dual-modality imaging to characterize neuronal and vasculature structures in the same animal for 3 months following electrode insertion. We find ongoing neuronal atrophy, but relative vascular stability, in close proximity to the electrode, along with evidence suggesting links between rare, abrupt hypoxic events and neuronal process atrophy.
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Affiliation(s)
- Cristin G Welle
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA; Departments of Neurosurgery and Physiology & Biophysics, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA.
| | - Yu-Rong Gao
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA; Department of Neuroscience and Multiphoton Imaging Core Facility, University of Rochester Medical Center, Rochester, NY, USA
| | - Meijun Ye
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA
| | - Andrea Lozzi
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA; Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Adam Boretsky
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA; Engility Corporation, San Antonio, TX, USA
| | - Erkinay Abliz
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA
| | - Daniel X Hammer
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA
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Solarana K, Ye M, Gao YR, Rafi H, Hammer DX. Longitudinal multimodal assessment of neurodegeneration and vascular remodeling correlated with signal degradation in chronic cortical silicon microelectrodes. NEUROPHOTONICS 2020; 7:015004. [PMID: 32042853 PMCID: PMC6991888 DOI: 10.1117/1.nph.7.1.015004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/14/2020] [Indexed: 05/19/2023]
Abstract
Significance: Cortically implanted microelectrode arrays provide a direct interface with neuronal populations and are used to restore movement capabilities and provide sensory feedback to patients with paralysis or amputation. Penetrating electrodes experience high rates of signal degradation within the first year that limit effectiveness and lead to eventual device failure. Aim: To assess vascular and neuronal changes over time in mice with implanted electrodes and examine the contribution of the brain tissue response to electrode performance. Approach: We used a multimodal approach combining in vivo electrophysiology and subcellular-level optical imaging. Results: At acute timescales, we observed structural damage from the mechanical trauma of electrode insertion, evidenced by severed dendrites in the electrode path and local hypofluorescence. Superficial vessel growth and remodeling occurred within the first few weeks in both electrode-implanted and window-only animals, but the deeper capillary growth evident in window-only animals was suppressed in electrode-implanted animals. After longer implantation periods, there was evidence of degeneration of transected dendrites superficial to the electrode path and localized neuronal cell body loss, along with deep vascular velocity changes near the electrode. Total spike rate (SR) across all animals reached a peak between 3 and 9 months postimplantation, then decreased. The local field potential signal remained relatively constant for up to 6 months, particularly in the high-gamma band, indicating long-term electrode viability and neuronal functioning at further distances from the electrode, but it showed a reduction in some animals at later time points. Most importantly, we found that progressive high-gamma and SR reductions both correlate positively with localized cell loss and decreasing capillary density within 100 μ m of the electrode. Conclusions: This multifaceted approach provided a more comprehensive picture of the ongoing biological response at the brain-electrode interface than can be achieved with postmortem histology alone and established a real-time relationship between electrophysiology and tissue damage.
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Affiliation(s)
- Krystyna Solarana
- Food and Drug Administration, Center for Radiological Devices, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Meijun Ye
- Food and Drug Administration, Center for Radiological Devices, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Yu-Rong Gao
- Food and Drug Administration, Center for Radiological Devices, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Harmain Rafi
- Food and Drug Administration, Center for Radiological Devices, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Daniel X. Hammer
- Food and Drug Administration, Center for Radiological Devices, Office of Science and Engineering Laboratories, Division of Biomedical Physics, Silver Spring, Maryland, United States
- Address all correspondence to Daniel X. Hammer, E-mail:
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Vasudevan S, Vo J, Shafer B, Nam AS, Vakoc BJ, Hammer DX. Toward optical coherence tomography angiography-based biomarkers to assess the safety of peripheral nerve electrostimulation. J Neural Eng 2019; 16:036024. [PMID: 30917357 PMCID: PMC6583899 DOI: 10.1088/1741-2552/ab1405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Peripheral nerves serve as a link between the central nervous system and its targets. Altering peripheral nerve activity through targeted electrical stimulation is being investigated as a therapy for modulating end organ function. To support rapid advancement in the field, novel approaches to predict and prevent nerve injury resulting from electrical stimulation must be developed to overcome the limitations of traditional histological methods. The present study aims to develop an optical imaging-based approach for real-time assessment of peripheral nerve injury associated with electrical stimulation. APPROACH We developed an optical coherence tomography (OCT) angiography system and a 3D printed stimulating nerve stabilizer (sNS) to assess the real-time microvascular and blood flow changes associated with electrical stimulation of peripheral nerves. We then compared the microvascular changes with established nerve function analysis and immunohistochemistry to correlate changes with nerve injury. MAIN RESULTS Electrical stimulation of peripheral nerves has a direct influence on vessel diameter and capillary flow. The stimulation used in this study did not alter motor function significantly, but a delayed onset of mechanical allodynia at lower thresholds was observed using a sensory function test. Immunohistochemical analysis pointed to an increased number of macrophages within nerve fascicles and axon sprouting potentially related to nerve injury. SIGNIFICANCE This study is the first to demonstrate the ability to image peripheral nerve microvasculature changes during electrical stimulation. This expands the knowledge in the field and can be used to develop potential biomarkers to predict nerve injury resulting from electrical stimulation.
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Affiliation(s)
- Srikanth Vasudevan
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States of America
| | - Jesse Vo
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States of America
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States of America
| | - Benjamin Shafer
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States of America
| | - Ahhyun S Nam
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, United States of America
| | - Benjamin J Vakoc
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, United States of America
| | - Daniel X Hammer
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, United States of America
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Shoffstall AJ, Paiz J, Miller D, Rial G, Willis M, Menendez D, Hostler S, Capadona JR. Potential for thermal damage to the blood-brain barrier during craniotomy: implications for intracortical recording microelectrodes. J Neural Eng 2018; 15:034001. [PMID: 29205169 PMCID: PMC6482047 DOI: 10.1088/1741-2552/aa9f32] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Our objective was to determine how readily disruption of the blood-brain barrier (BBB) occurred as a result of bone drilling during a craniotomy to implant microelectrodes in rat cortex. While the phenomenon of heat production during bone drilling is well known, practices to evade damage to the underlying brain tissue are inconsistently practiced and reported in the literature. APPROACH We conducted a review of the intracortical microelectrode literature to summarize typical approaches to mitigate drill heating during rodent craniotomies. Post mortem skull-surface and transient brain-surface temperatures were experimentally recorded using an infrared camera and thermocouple, respectively. A number of drilling conditions were tested, including varying drill speed and continuous versus intermittent contact. In vivo BBB permeability was assayed 1 h after the craniotomy procedure using Evans blue dye. MAIN RESULTS Of the reviewed papers that mentioned methods to mitigate thermal damage during craniotomy, saline irrigation was the most frequently cited (in six of seven papers). In post mortem tissues, we observed increases in skull-surface temperature ranging from +3 °C to +21 °C, dependent on drill speed. In vivo, pulsed-drilling (2 s-on/2 s-off) and slow-drilling speeds (1000 r.p.m.) were the most effective methods we studied to mitigate heating effects from drilling, while inconclusive results were obtained with saline irrigation. SIGNIFICANCE Neuroinflammation, initiated by damage to the BBB and perpetuated by the foreign body response, is thought to play a key role in premature failure of intracortical recording microelectrodes. This study demonstrates the extreme sensitivity of the BBB to overheating caused by bone drilling. To avoid damage to the BBB, the authors recommend that craniotomies be drilled with slow speeds and/or with intermittent drilling with complete removal of the drill from the skull during 'off' periods. While saline alone was ineffective at preventing overheating, its use is still recommended to remove bone dust from the surgical site and to augment other cooling methods.
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Affiliation(s)
- Andrew J. Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
- Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Blvd, 151 W/APT, Cleveland, OH 44106-1702, USA
| | - Jen Paiz
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
| | - David Miller
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
| | - Griffin Rial
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
| | - Mitchell Willis
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
| | - Dhariyat Menendez
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
| | - Stephen Hostler
- Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Jeffrey R. Capadona
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
- Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Blvd, 151 W/APT, Cleveland, OH 44106-1702, USA
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Prospects for a Robust Cortical Recording Interface. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00028-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Woeppel K, Yang Q, Cui XT. Recent Advances in Neural Electrode-Tissue Interfaces. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2017; 4:21-31. [PMID: 29423457 PMCID: PMC5798641 DOI: 10.1016/j.cobme.2017.09.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Neurotechnology is facing an exponential growth in the recent decades. Neural electrode-tissue interface research has been well recognized as an instrumental component of neurotechnology development. While satisfactory long-term performance was demonstrated in some applications, such as cochlear implants and deep brain stimulators, more advanced neural electrode devices requiring higher resolution for single unit recording or microstimulation still face significant challenges in reliability and longevity. In this article, we review the most recent findings that contribute to our current understanding of the sources of poor reliability and longevity in neural recording or stimulation, including the material failure, biological tissue response and the interplay between the two. The newly developed characterization tools are introduced from electrophysiology models, molecular and biochemical analysis, material characterization to live imaging. The effective strategies that have been applied to improve the interface are also highlighted. Finally, we discuss the challenges and opportunities in improving the interface and achieving seamless integration between the implanted electrodes and neural tissue both anatomically and functionally.
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Affiliation(s)
- Kevin Woeppel
- Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
| | - Qianru Yang
- Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
| | - Xinyan Tracy Cui
- Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
- McGowan Institute for Regenerative Medicine, University of Pittsburgh
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Nicolai EN, Trevathan JK, Ross EK, Lujan JL, Blaha CD, Bennet KE, Lee KH, Ludwig KA. Detection of Norepinephrine in Whole Blood via Fast Scan Cyclic Voltammetry. ... IEEE INTERNATIONAL SYMPOSIUM ON MEDICAL MEASUREMENTS AND APPLICATIONS : PROCEEDINGS. IEEE INTERNATIONAL SYMPOSIUM ON MEDICAL MEASUREMENTS AND APPLICATIONS 2017; 2017:111-116. [PMID: 29177248 PMCID: PMC5698011 DOI: 10.1109/memea.2017.7985859] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Bioelectronic Medicines is an emerging field that capitalizes on minimally-invasive technology to stimulate the autonomic nervous system in order to evoke therapeutic biomolecular changes at the end-organ. The goal of Bioelectronic Medicines is to realize both 'precision and personalized' medicine. 'Precise' stimulation of neural circuitry creates biomolecular changes targeted exactly where needed to maximize therapeutic effects while minimizing off-target changes associated with side-effects. The therapy is then 'personalized' by utilizing implanted sensors to measure the biomolecular concentrations at, or near, the end-organ of interest and continually adjusting therapy to account for patient-specific biological changes throughout the day. To realize the promise of Bioelectronic Medicines, there is a need for minimally invasive, real-time measurement of biomarkers associated with the effects of autonomic nerve stimulation to be used for continuous titration of therapy. In this study we examine the feasibility of using fast scan cyclic voltammetry (FSCV) to measure norepinephrine levels, a neurochemical relevant to end-organ function, directly from blood. FSCV is a well-understood method for measuring electroactive neurochemicals in the central nervous system with high temporal and high spatial resolution that has yet to be adapted to the study of the autonomic nervous system. The results demonstrate that while detecting the electroactive neurochemical norepinephrine in blood is more challenging than obtaining the same FSCV measurements in a buffer solution due to biofouling of the electrode, it is feasible to utilize a minimally invasive FSCV electrode to obtain neurochemical measurements in blood.
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Affiliation(s)
- Evan N Nicolai
- Neurologic Surgery, Mayo Clinic, Rochester MN, United States
| | | | - Erika K Ross
- Neurologic Surgery, Mayo Clinic, Rochester MN, United States
| | - J Luis Lujan
- Neurologic Surgery, Mayo Clinic, Rochester MN, United States
| | - Charles D Blaha
- Neurologic Surgery, Mayo Clinic, Rochester MN, United States
| | - Kevin E Bennet
- Neurologic Surgery, Mayo Clinic, Rochester MN, United States
| | - Kendall H Lee
- Neurologic Surgery, Mayo Clinic, Rochester MN, United States
| | - Kip A Ludwig
- Neurologic Surgery, Mayo Clinic, Rochester MN, United States
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