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Mueller NN, Kim Y, Ocoko MYM, Dernelle P, Kale I, Patwa S, Hermoso AC, Chirra D, Capadona JR, Hess-Dunning A. Effects of Micromachining on Anti-oxidant Elution from a Mechanically-Adaptive Polymer. JOURNAL OF MICROMECHANICS AND MICROENGINEERING : STRUCTURES, DEVICES, AND SYSTEMS 2024; 34:10.1088/1361-6439/ad27f7. [PMID: 38586082 PMCID: PMC10996452 DOI: 10.1088/1361-6439/ad27f7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Intracortical microelectrodes (IMEs) can be used to restore motor and sensory function as a part of brain-computer interfaces in individuals with neuromusculoskeletal disorders. However, the neuroinflammatory response to IMEs can result in their premature failure, leading to reduced therapeutic efficacy. Mechanically-adaptive, resveratrol-eluting (MARE) neural probes target two mechanisms believed to contribute to the neuroinflammatory response by reducing the mechanical mismatch between the brain tissue and device, as well as locally delivering an antioxidant therapeutic. To create the mechanically-adaptive substrate, a dispersion, casting, and evaporation method is used, followed by a microfabrication process to integrate functional recording electrodes on the material. Resveratrol release experiments were completed to generate a resveratrol release profile and demonstrated that the MARE probes are capable of long-term controlled release. Additionally, our results showed that resveratrol can be degraded by laser-micromachining, an important consideration for future device fabrication. Finally, the electrodes were shown to have a suitable impedance for single-unit neural recording and could record single units in vivo.
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Affiliation(s)
- Natalie N Mueller
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Youjoung Kim
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Mali Ya Mungu Ocoko
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Peter Dernelle
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Ishani Kale
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Simran Patwa
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Anna Clarissa Hermoso
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Deeksha Chirra
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Jeffrey R Capadona
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Allison Hess-Dunning
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
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2
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Sharafkhani N, Long JM, Adams SD, Kouzani AZ. A self-stiffening compliant intracortical microprobe. Biomed Microdevices 2024; 26:17. [PMID: 38345721 PMCID: PMC10861748 DOI: 10.1007/s10544-024-00700-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2024] [Indexed: 02/15/2024]
Abstract
Utilising a flexible intracortical microprobe to record/stimulate neurons minimises the incompatibility between the implanted microprobe and the brain, reducing tissue damage due to the brain micromotion. Applying bio-dissolvable coating materials temporarily makes a flexible microprobe stiff to tolerate the penetration force during insertion. However, the inability to adjust the dissolving time after the microprobe contact with the cerebrospinal fluid may lead to inaccuracy in the microprobe positioning. Furthermore, since the dissolving process is irreversible, any subsequent positioning error cannot be corrected by re-stiffening the microprobe. The purpose of this study is to propose an intracortical microprobe that incorporates two compressible structures to make the microprobe both adaptive to the brain during operation and stiff during insertion. Applying a compressive force by an inserter compresses the two compressible structures completely, resulting in increasing the equivalent elastic modulus. Thus, instant switching between stiff and soft modes can be accomplished as many times as necessary to ensure high-accuracy positioning while causing minimal tissue damage. The equivalent elastic modulus of the microprobe during operation is ≈ 23 kPa, which is ≈ 42% less than the existing counterpart, resulting in ≈ 46% less maximum strain generated on the surrounding tissue under brain longitudinal motion. The self-stiffening microprobe and surrounding neural tissue are simulated during insertion and operation to confirm the efficiency of the design. Two-photon polymerisation technology is utilised to 3D print the proposed microprobe, which is experimentally validated and inserted into a lamb's brain without buckling.
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Affiliation(s)
- Naser Sharafkhani
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - John M Long
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - Scott D Adams
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - Abbas Z Kouzani
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia.
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3
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Trotier A, Bagnoli E, Walski T, Evers J, Pugliese E, Lowery M, Kilcoyne M, Fitzgerald U, Biggs M. Micromotion Derived Fluid Shear Stress Mediates Peri-Electrode Gliosis through Mechanosensitive Ion Channels. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2301352. [PMID: 37518828 PMCID: PMC10520674 DOI: 10.1002/advs.202301352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/11/2023] [Indexed: 08/01/2023]
Abstract
The development of bioelectronic neural implant technologies has advanced significantly over the past 5 years, particularly in brain-machine interfaces and electronic medicine. However, neuroelectrode-based therapies require invasive neurosurgery and can subject neural tissues to micromotion-induced mechanical shear, leading to chronic inflammation, the formation of a peri-electrode void and the deposition of reactive glial scar tissue. These structures act as physical barriers, hindering electrical signal propagation and reducing neural implant functionality. Although well documented, the mechanisms behind the initiation and progression of these processes are poorly understood. Herein, in silico analysis of micromotion-induced peri-electrode void progression and gliosis is described. Subsequently, ventral mesencephalic cells exposed to milliscale fluid shear stress in vitro exhibited increased expression of gliosis-associated proteins and overexpression of mechanosensitive ion channels PIEZO1 (piezo-type mechanosensitive ion channel component 1) and TRPA1 (transient receptor potential ankyrin 1), effects further confirmed in vivo in a rat model of peri-electrode gliosis. Furthermore, in vitro analysis indicates that chemical inhibition/activation of PIEZO1 affects fluid shear stress mediated astrocyte reactivity in a mitochondrial-dependent manner. Together, the results suggest that mechanosensitive ion channels play a major role in the development of a peri-electrode void and micromotion-induced glial scarring at the peri-electrode region.
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Affiliation(s)
- Alexandre Trotier
- SFI Research Centre for Medical Devices (CÚRAM)University of GalwayGalwayH91 W2TYIreland
- Galway Neuroscience CentreUniversity of GalwayGalwayH91 W2TYIreland
| | - Enrico Bagnoli
- SFI Research Centre for Medical Devices (CÚRAM)University of GalwayGalwayH91 W2TYIreland
- Galway Neuroscience CentreUniversity of GalwayGalwayH91 W2TYIreland
| | - Tomasz Walski
- SFI Research Centre for Medical Devices (CÚRAM)University of GalwayGalwayH91 W2TYIreland
- Department of Biomedical EngineeringFaculty of Fundamental Problems of TechnologyWrocław University of Science and TechnologyWroclaw50‐370Poland
| | - Judith Evers
- School of Electrical and Electronic EngineeringUniversity College DublinDublin 4Ireland
| | - Eugenia Pugliese
- SFI Research Centre for Medical Devices (CÚRAM)University of GalwayGalwayH91 W2TYIreland
| | - Madeleine Lowery
- School of Electrical and Electronic EngineeringUniversity College DublinDublin 4Ireland
| | - Michelle Kilcoyne
- SFI Research Centre for Medical Devices (CÚRAM)University of GalwayGalwayH91 W2TYIreland
- Galway Neuroscience CentreUniversity of GalwayGalwayH91 W2TYIreland
- Carbohydrate Signalling GroupDiscipline of MicrobiologyUniversity of GalwayGalwayH91 W2TYIreland
| | - Una Fitzgerald
- SFI Research Centre for Medical Devices (CÚRAM)University of GalwayGalwayH91 W2TYIreland
- Galway Neuroscience CentreUniversity of GalwayGalwayH91 W2TYIreland
| | - Manus Biggs
- SFI Research Centre for Medical Devices (CÚRAM)University of GalwayGalwayH91 W2TYIreland
- Galway Neuroscience CentreUniversity of GalwayGalwayH91 W2TYIreland
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4
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Ziemba AM, Woodson MCC, Funnell JL, Wich D, Balouch B, Rende D, Amato DN, Bao J, Oprea I, Cao D, Bajalo N, Ereifej ES, Capadona JR, Palermo EF, Gilbert RJ. Development of a Slow-Degrading Polymerized Curcumin Coating for Intracortical Microelectrodes. ACS APPLIED BIO MATERIALS 2023; 6:806-818. [PMID: 36749645 DOI: 10.1021/acsabm.2c00969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Intracortical microelectrodes are used with brain-computer interfaces to restore lost limb function following nervous system injury. While promising, recording ability of intracortical microelectrodes diminishes over time due, in part, to neuroinflammation. As curcumin has demonstrated neuroprotection through anti-inflammatory activity, we fabricated a 300 nm-thick intracortical microelectrode coating consisting of a polyurethane copolymer of curcumin and polyethylene glycol (PEG), denoted as poly(curcumin-PEG1000 carbamate) (PCPC). The uniform PCPC coating reduced silicon wafer hardness by two orders of magnitude and readily absorbed water within minutes, demonstrating that the coating is soft and hydrophilic in nature. Using an in vitro release model, curcumin eluted from the PCPC coating into the supernatant over 1 week; the majority of the coating was intact after an 8-week incubation in buffer, demonstrating potential for longer term curcumin release and softness. Assessing the efficacy of PCPC within a rat intracortical microelectrode model in vivo, there were no significant differences in tissue inflammation, scarring, neuron viability, and myelin damage between the uncoated and PCPC-coated probes. As the first study to implant nonfunctional probes with a polymerized curcumin coating, we have demonstrated the biocompatibility of a PCPC coating and presented a starting point in the design of poly(pro-curcumin) polymers as coating materials for intracortical electrodes.
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Affiliation(s)
- Alexis M Ziemba
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Neuroscience Program, Department of Biological Sciences, Smith College, Northampton 01063, Massachusetts, United States
| | - Mary Clare Crochiere Woodson
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Jessica L Funnell
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Douglas Wich
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Bailey Balouch
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Deniz Rende
- Center for Materials, Devices, and Integrated Systems, Rensselaer Polytechnic Institute, 110 8th Street, Troy 12180-3590, New York, United States
| | - Dahlia N Amato
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Jonathan Bao
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Ingrid Oprea
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Dominica Cao
- Neuroscience Program, Department of Biological Sciences, Smith College, Northampton 01063, Massachusetts, United States
| | - Neda Bajalo
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Evon S Ereifej
- Veteran Affairs Ann Arbor Healthcare System, Ann Arbor 48104, Michigan, United States.,Department of Biomedical Engineering, University of Michigan, Ann Arbor 48104, Michigan, United States.,Department of Neurology, University of Michigan, Ann Arbor 48104, Michigan, United States.,United States Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland 44106, Ohio, United States
| | - Jeffrey R Capadona
- United States Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland 44106, Ohio, United States.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland 44106, Ohio, United States
| | - Edmund F Palermo
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Ryan J Gilbert
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
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5
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Al Abed A, Amatoury J, Khraiche M. Finite Element Modeling of Magnitude and Location of Brain Micromotion Induced Strain for Intracortical Implants. Front Neurosci 2022; 15:727715. [PMID: 35069092 PMCID: PMC8770436 DOI: 10.3389/fnins.2021.727715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 10/08/2021] [Indexed: 11/13/2022] Open
Abstract
Micromotion-induced stress remains one of the main determinants of life of intracortical implants. This is due to high stress leading to tissue injury, which in turn leads to an immune response coupled with a significant reduction in the nearby neural population and subsequent isolation of the implant. In this work, we develop a finite element model of the intracortical probe-tissue interface to study the effect of implant micromotion, implant thickness, and material properties on the strain levels induced in brain tissue. Our results showed that for stiff implants, the strain magnitude is dependent on the magnitude of the motion, where a micromotion increase from 1 to 10 μm induced an increase in the strain by an order of magnitude. For higher displacement over 10 μm, the change in the strain was relatively smaller. We also showed that displacement magnitude has no impact on the location of maximum strain and addressed the conflicting results in the literature. Further, we explored the effect of different probe materials [i.e., silicon, polyimide (PI), and polyvinyl acetate nanocomposite (PVAc-NC)] on the magnitude, location, and distribution of strain. Finally, we showed that strain distribution across cortical implants was in line with published results on the size of the typical glial response to the neural probe, further reaffirming that strain can be a precursor to the glial response.
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Affiliation(s)
- Ali Al Abed
- Department of Mechanical Engineering, American University of Beirut, Beirut, Lebanon
| | - Jason Amatoury
- Sleep and Upper Airway Research Group, Biomedical Engineering Program, American University of Beirut, Beirut, Lebanon
| | - Massoud Khraiche
- Neural Engineering and Nanobiosensors Group, Biomedical Engineering Program, American University of Beirut, Beirut, Lebanon
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6
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Kim Y, Ereifej ES, Schwartzman WE, Meade SM, Chen K, Rayyan J, Feng H, Aluri V, Mueller NN, Bhambra R, Bhambra S, Taylor DM, Capadona JR. Investigation of the Feasibility of Ventricular Delivery of Resveratrol to the Microelectrode Tissue Interface. MICROMACHINES 2021; 12:1446. [PMID: 34945296 PMCID: PMC8708660 DOI: 10.3390/mi12121446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/12/2021] [Accepted: 11/19/2021] [Indexed: 12/02/2022]
Abstract
(1) Background: Intracortical microelectrodes (IMEs) are essential to basic brain research and clinical brain-machine interfacing applications. However, the foreign body response to IMEs results in chronic inflammation and an increase in levels of reactive oxygen and nitrogen species (ROS/RNS). The current study builds on our previous work, by testing a new delivery method of a promising antioxidant as a means of extending intracortical microelectrodes performance. While resveratrol has shown efficacy in improving tissue response, chronic delivery has proven difficult because of its low solubility in water and low bioavailability due to extensive first pass metabolism. (2) Methods: Investigation of an intraventricular delivery of resveratrol in rats was performed herein to circumvent bioavailability hurdles of resveratrol delivery to the brain. (3) Results: Intraventricular delivery of resveratrol in rats delivered resveratrol to the electrode interface. However, intraventricular delivery did not have a significant impact on electrophysiological recordings over the six-week study. Histological findings indicated that rats receiving intraventricular delivery of resveratrol had a decrease of oxidative stress, yet other biomarkers of inflammation were found to be not significantly different from control groups. However, investigation of the bioavailability of resveratrol indicated a decrease in resveratrol accumulation in the brain with time coupled with inconsistent drug elution from the cannulas. Further inspection showed that there may be tissue or cellular debris clogging the cannulas, resulting in variable elution, which may have impacted the results of the study. (4) Conclusions: These results indicate that the intraventricular delivery approach described herein needs further optimization, or may not be well suited for this application.
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Affiliation(s)
- Youjoung Kim
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Evon S. Ereifej
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
- Veteran Affairs Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - William E. Schwartzman
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Seth M. Meade
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Keying Chen
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Jacob Rayyan
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - He Feng
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Varoon Aluri
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Natalie N. Mueller
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Raman Bhambra
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Sahaj Bhambra
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Dawn M. Taylor
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
- Cleveland Functional Electrical Stimulation Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Rehabilitation Research and Development, Cleveland, OH 44106, USA
- Department of Neurosciences, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Jeffrey R. Capadona
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
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7
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Kim K, Sung C, Lee J, Won J, Jeon W, Seo S, Yoon K, Park S. Computational and Histological Analyses for Investigating Mechanical Interaction of Thermally Drawn Fiber Implants with Brain Tissue. MICROMACHINES 2021; 12:mi12040394. [PMID: 33918390 PMCID: PMC8067235 DOI: 10.3390/mi12040394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/25/2021] [Accepted: 03/31/2021] [Indexed: 01/24/2023]
Abstract
The development of a compliant neural probe is necessary to achieve chronic implantation with minimal signal loss. Although fiber-based neural probes fabricated by the thermal drawing process have been proposed as a solution, their long-term effect on the brain has not been thoroughly investigated. Here, we examined the mechanical interaction of thermally drawn fiber implants with neural tissue through computational and histological analyses. Specifically, finite element analysis and immunohistochemistry were conducted to evaluate the biocompatibility of various fiber implants made with different base materials (steel, silica, polycarbonate, and hydrogel). Moreover, the effects of the coefficient of friction and geometric factors including aspect ratio and the shape of the cross-section on the strain were investigated with the finite element model. As a result, we observed that the fiber implants fabricated with extremely softer material such as hydrogel exhibited significantly lower strain distribution and elicited a reduced immune response. In addition, the implants with higher coefficient of friction (COF) and/or circular cross-sections showed a lower strain distribution and smaller critical volume. This work suggests the materials and design factors that need to be carefully considered to develop future fiber-based neural probes to minimize mechanical invasiveness.
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Affiliation(s)
- Kanghyeon Kim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Deajeon 34141, Korea; (K.K.); (C.S.); (W.J.)
| | - Changhoon Sung
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Deajeon 34141, Korea; (K.K.); (C.S.); (W.J.)
| | - Jungjoon Lee
- Program of Brain and Cognitive Engineering, Korea Advanced Institute of Science and Technology (KAIST), Deajeon 34141, Korea; (J.L.); (J.W.)
| | - Joonhee Won
- Program of Brain and Cognitive Engineering, Korea Advanced Institute of Science and Technology (KAIST), Deajeon 34141, Korea; (J.L.); (J.W.)
| | - Woojin Jeon
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Deajeon 34141, Korea; (K.K.); (C.S.); (W.J.)
| | - Seungbeom Seo
- Department of Electrical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea;
| | - Kyungho Yoon
- Center for Healthcare Robotics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea
- Correspondence: (K.Y.); (S.P.)
| | - Seongjun Park
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Deajeon 34141, Korea; (K.K.); (C.S.); (W.J.)
- Program of Brain and Cognitive Engineering, Korea Advanced Institute of Science and Technology (KAIST), Deajeon 34141, Korea; (J.L.); (J.W.)
- KAIST Institute of Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Correspondence: (K.Y.); (S.P.)
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8
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Investigating the Association between Motor Function, Neuroinflammation, and Recording Metrics in the Performance of Intracortical Microelectrode Implanted in Motor Cortex. MICROMACHINES 2020; 11:mi11090838. [PMID: 32899336 PMCID: PMC7570280 DOI: 10.3390/mi11090838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 11/26/2022]
Abstract
Long-term reliability of intracortical microelectrodes remains a challenge for increased acceptance and deployment. There are conflicting reports comparing measurements associated with recording quality with postmortem histology, in attempts to better understand failure of intracortical microelectrodes (IMEs). Our group has recently introduced the assessment of motor behavior tasks as another metric to evaluate the effects of IME implantation. We hypothesized that adding the third dimension to our analysis, functional behavior testing, could provide substantial insight on the health of the tissue, success of surgery/implantation, and the long-term performance of the implanted device. Here we present our novel analysis scheme including: (1) the use of numerical formal concept analysis (nFCA) and (2) a regression analysis utilizing modern model/variable selection. The analyses found complimentary relationships between the variables. The histological variables for glial cell activation had associations between each other, as well as the neuronal density around the electrode interface. The neuronal density had associations to the electrophysiological recordings and some of the motor behavior metrics analyzed. The novel analyses presented herein describe a valuable tool that can be utilized to assess and understand relationships between diverse variables being investigated. These models can be applied to a wide range of ongoing investigations utilizing various devices and therapeutics.
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