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O'Sullivan KP, Coats B. Coupled Eulerian-Lagrangian model prediction of neural tissue strain during microelectrode insertion. J Neural Eng 2024; 21:046055. [PMID: 39074496 DOI: 10.1088/1741-2552/ad68a6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 07/29/2024] [Indexed: 07/31/2024]
Abstract
Objective.Implanted neural microelectrodes are an important tool for recording from and stimulating the cerebral cortex. The performance of chronically implanted devices, however, is often hindered by the development of a reactive tissue response. Previous computational models have investigated brain strain from micromotions of neural electrodes after they have been inserted, to investigate design parameters that might minimize triggers to the reactive tissue response. However, these models ignore tissue damage created during device insertion, an important contributing factor to the severity of inflammation. The objective of this study was to evaluate the effect of electrode geometry, insertion speed, and surface friction on brain tissue strain during insertion.Approach. Using a coupled Eulerian-Lagrangian approach, we developed a 3D finite element model (FEM) that simulates the dynamic insertion of a neural microelectrode in brain tissue. Geometry was varied to investigate tip bluntness, cross-sectional shape, and shank thickness. Insertion velocities were varied from 1 to 8 m s-1. Friction was varied from frictionless to 0.4. Tissue strain and potential microvasculature hemorrhage radius were evaluated for brain regions along the electrode shank and near its tip.Main results. Sharper tips resulted in higher mean max principal strains near the tip except for the bluntest tip on the square cross-section electrode, which exhibited high compressive strain values due to stress concentrations at the corners. The potential vascular damage radius around the electrode was primarily a function of the shank diameter, with smaller shank diameters resulting in smaller distributions of radial strain around the electrode. However, the square shank interaction with the tip taper length caused unique strain distributions that increased the damage radius in some cases. Faster insertion velocities created more strain near the tip but less strain along the shank. Increased friction between the brain and electrode created more strain near the electrode tip and along the shank, but frictionless interactions resulted in increased tearing of brain tissue near the tip.Significance. These results demonstrate the first dynamic FEM study of neural electrode insertion, identifying design factors that can reduce tissue strain and potentially mitigate initial reactive tissue responses due to traumatic microelectrode array insertion.
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Affiliation(s)
- K P O'Sullivan
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States of America
| | - B Coats
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, United States of America
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Wu B, Castagnola E, McClung CA, Cui XT. PEDOT/CNT Flexible MEAs Reveal New Insights into the Clock Gene's Role in Dopamine Dynamics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2308212. [PMID: 38430532 PMCID: PMC11251561 DOI: 10.1002/advs.202308212] [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: 10/31/2023] [Revised: 01/26/2024] [Indexed: 03/04/2024]
Abstract
Substantial evidence has shown that the Circadian Locomotor Output Cycles Kaput (Clock) gene is a core transcription factor of circadian rhythms that regulates dopamine (DA) synthesis. To shed light on the mechanism of this interaction, flexible multielectrode arrays (MEAs) are developed that can measure both DA concentrations and electrophysiology chronically. The dual functionality is enabled by conducting polymer PEDOT doped with acid-functionalized carbon nanotubes (CNT). The PEDOT/CNT microelectrode coating maintained stable electrochemical impedance and DA detection by square wave voltammetry for 4 weeks in vitro. When implanted in wild-type (WT) and Clock mutation (MU) mice, MEAs measured tonic DA concentration and extracellular neural activity with high spatial and temporal resolution for 4 weeks. A diurnal change of DA concentration in WT is observed, but not in MU, and a higher basal DA concentration and stronger cocaine-induced DA increase in MU. Meanwhile, striatal neuronal firing rate is found to be positively correlated with DA concentration in both animal groups. These findings offer new insights into DA dynamics in the context of circadian rhythm regulation, and the chronically reliable performance and dual measurement capability of this technology hold great potential for a broad range of neuroscience research.
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Affiliation(s)
- Bingchen Wu
- Department of BioengineeringUniversity of PittsburghPittsburghPA15213USA
- Center for the Neural Basis of CognitionPittsburghPA15213USA
| | - Elisa Castagnola
- Department of BioengineeringUniversity of PittsburghPittsburghPA15213USA
- Department of Biomedical EngineeringLouisiana Tech UniversityRustonLA71272USA
| | | | - Xinyan Tracy Cui
- Department of BioengineeringUniversity of PittsburghPittsburghPA15213USA
- Center for the Neural Basis of CognitionPittsburghPA15213USA
- McGowan Institute for Regenerative MedicinePittsburghPA15219USA
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3
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Malekoshoaraie MH, Wu B, Krahe DD, Ahmed Z, Pupa S, Jain V, Cui XT, Chamanzar M. Fully flexible implantable neural probes for electrophysiology recording and controlled neurochemical modulation. MICROSYSTEMS & NANOENGINEERING 2024; 10:91. [PMID: 38947533 PMCID: PMC11211464 DOI: 10.1038/s41378-024-00685-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 02/01/2024] [Accepted: 02/28/2024] [Indexed: 07/02/2024]
Abstract
Targeted delivery of neurochemicals and biomolecules for neuromodulation of brain activity is a powerful technique that, in addition to electrical recording and stimulation, enables a more thorough investigation of neural circuit dynamics. We have designed a novel, flexible, implantable neural probe capable of controlled, localized chemical stimulation and electrophysiology recording. The neural probe was implemented using planar micromachining processes on Parylene C, a mechanically flexible, biocompatible substrate. The probe shank features two large microelectrodes (chemical sites) for drug loading and sixteen small microelectrodes for electrophysiology recording to monitor neuronal response to drug release. To reduce the impedance while keeping the size of the microelectrodes small, poly(3,4-ethylenedioxythiophene) (PEDOT) was electrochemically coated on recording microelectrodes. In addition, PEDOT doped with mesoporous sulfonated silica nanoparticles (SNPs) was used on chemical sites to achieve controlled, electrically-actuated drug loading and releasing. Different neurotransmitters, including glutamate (Glu) and gamma-aminobutyric acid (GABA), were incorporated into the SNPs and electrically triggered to release repeatedly. An in vitro experiment was conducted to quantify the stimulated release profile by applying a sinusoidal voltage (0.5 V, 2 Hz). The flexible neural probe was implanted in the barrel cortex of the wild-type Sprague Dawley rats. As expected, due to their excitatory and inhibitory effects, Glu and GABA release caused a significant increase and decrease in neural activity, respectively, which was recorded by the recording microelectrodes. This novel flexible neural probe technology, combining on-demand chemical release and high-resolution electrophysiology recording, is an important addition to the neuroscience toolset used to dissect neural circuitry and investigate neural network connectivity.
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Affiliation(s)
| | - Bingchen Wu
- Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260 USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittburgh, 15213 USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, 15219 USA
| | - Daniela D. Krahe
- Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Zabir Ahmed
- Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 USA
| | - Stephen Pupa
- Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 USA
| | - Vishal Jain
- Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 USA
| | - Xinyan Tracy Cui
- Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260 USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittburgh, 15213 USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, 15219 USA
| | - Maysamreza Chamanzar
- Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 USA
- Carnegie Mellon Neuroscience Institute, Carnegie Mellon University, Pittsburgh, 15213 USA
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4
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McNamara IN, Wellman SM, Li L, Eles JR, Savya S, Sohal HS, Angle MR, Kozai TDY. Electrode sharpness and insertion speed reduce tissue damage near high-density penetrating arrays. J Neural Eng 2024; 21:026030. [PMID: 38518365 DOI: 10.1088/1741-2552/ad36e1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/22/2024] [Indexed: 03/24/2024]
Abstract
Objective. Over the past decade, neural electrodes have played a crucial role in bridging biological tissues with electronic and robotic devices. This study focuses on evaluating the optimal tip profile and insertion speed for effectively implanting Paradromics' high-density fine microwire arrays (FμA) prototypes into the primary visual cortex (V1) of mice and rats, addressing the challenges associated with the 'bed-of-nails' effect and tissue dimpling.Approach. Tissue response was assessed by investigating the impact of electrodes on the blood-brain barrier (BBB) and cellular damage, with a specific emphasis on tailored insertion strategies to minimize tissue disruption during electrode implantation.Main results.Electro-sharpened arrays demonstrated a marked reduction in cellular damage within 50μm of the electrode tip compared to blunt and angled arrays. Histological analysis revealed that slow insertion speeds led to greater BBB compromise than fast and pneumatic methods. Successful single-unit recordings validated the efficacy of the optimized electro-sharpened arrays in capturing neural activity.Significance.These findings underscore the critical role of tailored insertion strategies in minimizing tissue damage during electrode implantation, highlighting the suitability of electro-sharpened arrays for long-term implant applications. This research contributes to a deeper understanding of the complexities associated with high-channel-count microelectrode array implantation, emphasizing the importance of meticulous assessment and optimization of key parameters for effective integration and minimal tissue disruption. By elucidating the interplay between insertion parameters and tissue response, our study lays a strong foundation for the development of advanced implantable devices with a reduction in reactive gliosis and improved performance in neural recording applications.
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Affiliation(s)
- Ingrid N McNamara
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Lehong Li
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Sajishnu Savya
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | | | | | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center of the Basis of Neural Cognition, Pittsburgh, PA, United States of America
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
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5
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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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6
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Perna A, Angotzi GN, Berdondini L, Ribeiro JF. Advancing the interfacing performances of chronically implantable neural probes in the era of CMOS neuroelectronics. Front Neurosci 2023; 17:1275908. [PMID: 38027514 PMCID: PMC10644322 DOI: 10.3389/fnins.2023.1275908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 10/10/2023] [Indexed: 12/01/2023] Open
Abstract
Tissue penetrating microelectrode neural probes can record electrophysiological brain signals at resolutions down to single neurons, making them invaluable tools for neuroscience research and Brain-Computer-Interfaces (BCIs). The known gradual decrease of their electrical interfacing performances in chronic settings, however, remains a major challenge. A key factor leading to such decay is Foreign Body Reaction (FBR), which is the cascade of biological responses that occurs in the brain in the presence of a tissue damaging artificial device. Interestingly, the recent adoption of Complementary Metal Oxide Semiconductor (CMOS) technology to realize implantable neural probes capable of monitoring hundreds to thousands of neurons simultaneously, may open new opportunities to face the FBR challenge. Indeed, this shift from passive Micro Electro-Mechanical Systems (MEMS) to active CMOS neural probe technologies creates important, yet unexplored, opportunities to tune probe features such as the mechanical properties of the probe, its layout, size, and surface physicochemical properties, to minimize tissue damage and consequently FBR. Here, we will first review relevant literature on FBR to provide a better understanding of the processes and sources underlying this tissue response. Methods to assess FBR will be described, including conventional approaches based on the imaging of biomarkers, and more recent transcriptomics technologies. Then, we will consider emerging opportunities offered by the features of CMOS probes. Finally, we will describe a prototypical neural probe that may meet the needs for advancing clinical BCIs, and we propose axial insertion force as a potential metric to assess the influence of probe features on acute tissue damage and to control the implantation procedure to minimize iatrogenic injury and subsequent FBR.
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Affiliation(s)
- Alberto Perna
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
- The Open University Affiliated Research Centre at Istituto Italiano di Tecnologia (ARC@IIT), Istituto Italiano di Tecnologia, Genova, Italy
| | - Gian Nicola Angotzi
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
| | - Luca Berdondini
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
| | - João Filipe Ribeiro
- Microtechnology for Neuroelectronics Lab, Fondazione Istituto Italiano di Tecnologia, Neuroscience and Brain Technologies, Genova, Italy
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7
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Gregory BA, Thompson CH, Salatino JW, Railing MJ, Zimmerman AF, Gupta B, Williams K, Beatty JA, Cox CL, Purcell EK. Structural and functional changes of deep layer pyramidal neurons surrounding microelectrode arrays implanted in rat motor cortex. Acta Biomater 2023; 168:429-439. [PMID: 37499727 PMCID: PMC10441615 DOI: 10.1016/j.actbio.2023.07.027] [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] [Received: 03/14/2023] [Revised: 06/25/2023] [Accepted: 07/18/2023] [Indexed: 07/29/2023]
Abstract
Devices capable of recording or stimulating neuronal signals have created new opportunities to understand normal physiology and treat sources of pathology in the brain. However, it is possible that the tissue response to implanted electrodes may influence the nature of the signals detected or stimulated. In this study, we characterized structural and functional changes in deep layer pyramidal neurons surrounding silicon or polyimide-based electrodes implanted in the motor cortex of rats. Devices were captured in 300 µm-thick tissue slices collected at the 1 or 6 week time point post-implantation, and individual neurons were assessed using a combination of whole-cell electrophysiology and 2-photon imaging. We observed disrupted dendritic arbors and a significant reduction in spine densities in neurons surrounding devices. These effects were accompanied by a decrease in the frequency of spontaneous excitatory post-synaptic currents, a reduction in sag amplitude, an increase in spike frequency adaptation, and an increase in filopodia density. We hypothesize that the effects observed in this study may contribute to the signal loss and instability that often accompany chronically implanted electrodes. STATEMENT OF SIGNIFICANCE: Implanted electrodes in the brain can be used to treat sources of pathology and understand normal physiology by recording or stimulating electrical signals generated by local neurons. However, a foreign body response following implantation undermines the performance of these devices. While several studies have investigated the biological mechanisms of device-tissue interactions through histology, transcriptomics, and imaging, our study is the first to directly interrogate effects on the function of neurons surrounding electrodes using single-cell electrophysiology. Additionally, we provide new, detailed assessments of the impacts of electrodes on the dendritic structure and spine morphology of neurons, and we assess effects for both traditional (silicon) and newer polymer electrode materials. These results reveal new potential mechanisms of electrode-tissue interactions.
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Affiliation(s)
| | - Cort H Thompson
- Department of Biomedical Engineering, Michigan State University, United States
| | - Joseph W Salatino
- Department of Biomedical Engineering, Michigan State University, United States
| | - Mia J Railing
- Department of Physiology, Michigan State University, United States
| | | | - Bhavna Gupta
- Neuroscience Program, Michigan State University, United States
| | - Kathleen Williams
- Department of Biomedical Engineering, Michigan State University, United States
| | - Joseph A Beatty
- Department of Physiology, Michigan State University, United States; Neuroscience Program, Michigan State University, United States
| | - Charles L Cox
- Department of Physiology, Michigan State University, United States; Neuroscience Program, Michigan State University, United States
| | - Erin K Purcell
- Department of Biomedical Engineering, Michigan State University, United States; Neuroscience Program, Michigan State University, United States; Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, United States.
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8
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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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Li Y, Li N, Liu W, Prominski A, Kang S, Dai Y, Liu Y, Hu H, Wai S, Dai S, Cheng Z, Su Q, Cheng P, Wei C, Jin L, Hubbell JA, Tian B, Wang S. Achieving tissue-level softness on stretchable electronics through a generalizable soft interlayer design. Nat Commun 2023; 14:4488. [PMID: 37495580 PMCID: PMC10372055 DOI: 10.1038/s41467-023-40191-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 07/18/2023] [Indexed: 07/28/2023] Open
Abstract
Soft and stretchable electronics have emerged as highly promising tools for biomedical diagnosis and biological studies, as they interface intimately with the human body and other biological systems. Most stretchable electronic materials and devices, however, still have Young's moduli orders of magnitude higher than soft bio-tissues, which limit their conformability and long-term biocompatibility. Here, we present a design strategy of soft interlayer for allowing the use of existing stretchable materials of relatively high moduli to versatilely realize stretchable devices with ultralow tissue-level moduli. We have demonstrated stretchable transistor arrays and active-matrix circuits with moduli below 10 kPa-over two orders of magnitude lower than the current state of the art. Benefiting from the increased conformability to irregular and dynamic surfaces, the ultrasoft device created with the soft interlayer design realizes electrophysiological recording on an isolated heart with high adaptability, spatial stability, and minimal influence on ventricle pressure. In vivo biocompatibility tests also demonstrate the benefit of suppressing foreign-body responses for long-term implantation. With its general applicability to diverse materials and devices, this soft-interlayer design overcomes the material-level limitation for imparting tissue-level softness to a variety of bioelectronic devices.
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Affiliation(s)
- Yang Li
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Nan Li
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Wei Liu
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | | | - Seounghun Kang
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Yahao Dai
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Youdi Liu
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Huawei Hu
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Shinya Wai
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Shilei Dai
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Zhe Cheng
- Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA
| | - Qi Su
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Ping Cheng
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Chen Wei
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Lihua Jin
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Jeffrey A Hubbell
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA
| | - Bozhi Tian
- Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA
| | - Sihong Wang
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA.
- Nanoscience and Technology Division and Center for Molecular Engineering, Argonne National Laboratory, Lemont, IL, 60439, USA.
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10
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Luan L, Yin R, Zhu H, Xie C. Emerging Penetrating Neural Electrodes: In Pursuit of Large Scale and Longevity. Annu Rev Biomed Eng 2023; 25:185-205. [PMID: 37289556 PMCID: PMC11078330 DOI: 10.1146/annurev-bioeng-090622-050507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Penetrating neural electrodes provide a powerful approach to decipher brain circuitry by allowing for time-resolved electrical detections of individual action potentials. This unique capability has contributed tremendously to basic and translational neuroscience, enabling both fundamental understandings of brain functions and applications of human prosthetic devices that restore crucial sensations and movements. However, conventional approaches are limited by the scarce number of available sensing channels and compromised efficacy over long-term implantations. Recording longevity and scalability have become the most sought-after improvements in emerging technologies. In this review, we discuss the technological advances in the past 5-10 years that have enabled larger-scale, more detailed, and longer-lasting recordings of neural circuits at work than ever before. We present snapshots of the latest advances in penetration electrode technology, showcase their applications in animal models and humans, and outline the underlying design principles and considerations to fuel future technological development.
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Affiliation(s)
- Lan Luan
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
- Department of Bioengineering, Rice University, Houston, Texas, USA
| | - Rongkang Yin
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
| | - Hanlin Zhu
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas, USA;
- Rice Neuroengineering Initiative, Rice University, Houston, Texas, USA
- Department of Bioengineering, Rice University, Houston, Texas, USA
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11
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Imaichi-Kobayashi S, Kassab R, Piersigilli A, Robertson R, Leonard C, Long N, Dean B, Phaneuf M, Ling V. An electrospun macrodevice for durable encapsulation of human cells with consistent secretion of therapeutic antibodies. Biomaterials 2023; 298:122123. [PMID: 37172505 DOI: 10.1016/j.biomaterials.2023.122123] [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: 09/15/2022] [Revised: 03/31/2023] [Accepted: 04/08/2023] [Indexed: 05/15/2023]
Abstract
Frequent subcutaneous or intravenous administrations of therapeutic biomolecules can be costly and inconvenient for patients. Implantation of encapsulated recombinant cells represents a promising approach for the sustained delivery of biotherapeutics. However, foreign body and fibrotic response against encapsulation materials results in drastically reduced viability of encapsulated cells, presenting a major engineering challenge for biocompatibility. Here, we show that the multi-laminate electrospun retrievable macrodevice (Bio-Spun) protects genetically modified human cells after subcutaneous implant in mice. We describe here a biocompatible nanofiber device that limits fibrosis and extends implant survival. For more than 150 days, these devices supported human cells engineered to secrete the antibodies: vedolizumab, ustekinumab, and adalimumab, while eliciting minimal fibrotic response in mice. The porous electrospun cell chamber allowed secretion of the recombinant antibodies into the host bloodstream, and prevented infiltration of host cells into the chamber. High plasma levels (>50 μg/mL) of antibody were maintained in the optimized devices for more than 5 months. Our findings demonstrate that macrodevices constructed from electrospun materials are effective in protecting genetically engineered cells for the sustained administration of recombinant therapeutic antibodies.
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Affiliation(s)
| | | | - Alessandra Piersigilli
- Department of Drug Safety Research and Evaluation, Takeda Pharmaceuticals, Cambridge, MA, USA
| | | | - Christopher Leonard
- Department of Drug Safety Research and Evaluation, Takeda Pharmaceuticals, Cambridge, MA, USA
| | | | | | | | - Vincent Ling
- Department of Pharmaceutical Science, Takeda Pharmaceuticals, Cambridge, MA, USA.
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12
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Wang Y, Yang X, Zhang X, Wang Y, Pei W. Implantable intracortical microelectrodes: reviewing the present with a focus on the future. MICROSYSTEMS & NANOENGINEERING 2023; 9:7. [PMID: 36620394 PMCID: PMC9814492 DOI: 10.1038/s41378-022-00451-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 08/08/2022] [Accepted: 08/22/2022] [Indexed: 06/17/2023]
Abstract
Implantable intracortical microelectrodes can record a neuron's rapidly changing action potentials (spikes). In vivo neural activity recording methods often have either high temporal or spatial resolution, but not both. There is an increasing need to record more neurons over a longer duration in vivo. However, there remain many challenges to overcome before achieving long-term, stable, high-quality recordings and realizing comprehensive, accurate brain activity analysis. Based on the vision of an idealized implantable microelectrode device, the performance requirements for microelectrodes are divided into four aspects, including recording quality, recording stability, recording throughput, and multifunctionality, which are presented in order of importance. The challenges and current possible solutions for implantable microelectrodes are given from the perspective of each aspect. The current developments in microelectrode technology are analyzed and summarized.
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Affiliation(s)
- Yang Wang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xinze Yang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xiwen Zhang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yijun Wang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
- Chinese Institute for Brain Research, 102206 Beijing, China
| | - Weihua Pei
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
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13
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Merken L, Schelles M, Ceyssens F, Kraft M, Janssen P. Thin flexible arrays for long-term multi-electrode recordings in macaque primary visual cortex. J Neural Eng 2022; 19. [PMID: 36215972 DOI: 10.1088/1741-2552/ac98e2] [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: 06/17/2022] [Accepted: 10/10/2022] [Indexed: 01/11/2023]
Abstract
Objective.Basic, translational and clinical neuroscience are increasingly focusing on large-scale invasive recordings of neuronal activity. However, in large animals such as nonhuman primates and humans-in which the larger brain size with sulci and gyri imposes additional challenges compared to rodents, there is a huge unmet need to record from hundreds of neurons simultaneously anywhere in the brain for long periods of time. Here, we tested the electrical and mechanical properties of thin, flexible multi-electrode arrays (MEAs) inserted into the primary visual cortex of two macaque monkeys, and assessed their magnetic resonance imaging (MRI) compatibility and their capacity to record extracellular activity over a period of 1 year.Approach.To allow insertion of the floating arrays into the visual cortex, the 20 by 100µm2shafts were temporarily strengthened by means of a resorbable poly(lactic-co-glycolic acid) coating.Main results. After manual insertion of the arrays, theex vivoandin vivoMRI compatibility of the arrays proved to be excellent. We recorded clear single-unit activity from up to 50% of the electrodes, and multi-unit activity (MUA) on 60%-100% of the electrodes, which allowed detailed measurements of the receptive fields and the orientation selectivity of the neurons. Even 1 year after insertion, we obtained significant MUA responses on 70%-100% of the electrodes, while the receptive fields remained remarkably stable over the entire recording period.Significance.Thus, the thin and flexible MEAs we tested offer several crucial advantages compared to existing arrays, most notably in terms of brain tissue compliance, scalability, and brain coverage. Future brain-machine interface applications in humans may strongly benefit from this new generation of chronically implanted MEAs.
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Affiliation(s)
- Lara Merken
- Laboratory for Neuro- and Psychophysiology, KU Leuven, Leuven 3000, Belgium.,Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Maarten Schelles
- Micro- and Nanosystems (MNS), Electrical Engineering Department (ESAT), KU Leuven, Leuven 3000, Belgium.,ReVision Implant NV, Haasrode 3053, Belgium
| | | | - Michael Kraft
- Micro- and Nanosystems (MNS), Electrical Engineering Department (ESAT), KU Leuven, Leuven 3000, Belgium.,Leuven Institute for Micro- and Nanotechnology (LIMNI), Leuven 3000, Belgium
| | - Peter Janssen
- Laboratory for Neuro- and Psychophysiology, KU Leuven, Leuven 3000, Belgium.,Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
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14
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Zhou Y, Gu C, Liang J, Zhang B, Yang H, Zhou Z, Li M, Sun L, Tao TH, Wei X. A silk-based self-adaptive flexible opto-electro neural probe. MICROSYSTEMS & NANOENGINEERING 2022; 8:118. [PMID: 36389054 PMCID: PMC9643444 DOI: 10.1038/s41378-022-00461-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 09/15/2022] [Accepted: 10/09/2022] [Indexed: 06/16/2023]
Abstract
The combination of optogenetics and electrophysiological recording enables high-precision bidirectional interactions between neural interfaces and neural circuits, which provides a promising approach for the study of progressive neurophysiological phenomena. Opto-electrophysiological neural probes with sufficient flexibility and biocompatibility are desirable to match the low mechanical stiffness of brain tissue for chronic reliable performance. However, lack of rigidity poses challenges for the accurate implantation of flexible neural probes with less invasiveness. Herein, we report a hybrid probe (Silk-Optrode) consisting of a silk protein optical fiber and multiple flexible microelectrode arrays. The Silk-Optrode can be accurately inserted into the brain and perform synchronized optogenetic stimulation and multichannel recording in freely behaving animals. Silk plays an important role due to its high transparency, excellent biocompatibility, and mechanical controllability. Through the hydration of the silk optical fiber, the Silk-Optrode probe enables itself to actively adapt to the environment after implantation and reduce its own mechanical stiffness to implant into the brain with high fidelity while maintaining mechanical compliance with the surrounding tissue. The probes with 128 recording channels can detect high-yield well-isolated single units while performing intracranial light stimulation with low optical losses, surpassing previous work of a similar type. Two months of post-surgery results suggested that as-reported Silk-Optrode probes exhibit better implant-neural interfaces with less immunoreactive glial responses and tissue lesions. A silk optical fiber-based Silk-Optrode probe consisting of a natural silk optical fiber and a flexible micro/nano electrode array is reported. The multifunctional soft probe can modify its own Young's modulus through hydration to achieve accurate implantation into the brain. The low optical loss and single-unit recording abilities allow simultaneous optogenetic stimulation and multichannel readout, which expands the applications in the operation and parsing of neural circuits in behavioral animals.
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Affiliation(s)
- Yu Zhou
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- School of Graduate Study, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Chi Gu
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- School of Graduate Study, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Jizhi Liang
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- School of Graduate Study, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Bohan Zhang
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- School of Physical Science and Technology, ShanghaiTech University, 200031 Shanghai, China
| | - Huiran Yang
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
| | - Zhitao Zhou
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- School of Graduate Study, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Meng Li
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- School of Graduate Study, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Liuyang Sun
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- School of Graduate Study, University of Chinese Academy of Sciences, 100049 Beijing, China
- 2020 X-Lab, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
| | - Tiger H. Tao
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- School of Graduate Study, University of Chinese Academy of Sciences, 100049 Beijing, China
- School of Physical Science and Technology, ShanghaiTech University, 200031 Shanghai, China
- 2020 X-Lab, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, 100049 Beijing, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, 200031 Shanghai, China
- Neuroxess Co., Ltd. (Jiangxi), 330029 Nanchang, Jiangxi China
- Guangdong Institute of Intelligence Science and Technology, Hengqin, 519031 Zhuhai, Guangdong China
- Tianqiao and Chrissy Chen Institute for Translational Research, Shanghai, China
| | - Xiaoling Wei
- State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- School of Graduate Study, University of Chinese Academy of Sciences, 100049 Beijing, China
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15
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Naveen NR, Girirajasekhar D, Goudanavar PS, Kumar CB, Narasimha GL. Prospection of Microfluidics for Local Drug Delivery. Curr Drug Targets 2022; 23:1239-1251. [PMID: 35379132 DOI: 10.2174/1389450123666220404154710] [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: 08/16/2021] [Revised: 01/03/2022] [Accepted: 02/10/2022] [Indexed: 01/25/2023]
Abstract
Significant endeavors can be made to develop effective drug delivery systems. Nowadays, many of these novel systems have gained attention as they focus primarily on increasing the bioavailability and bioaccessibility of several drugs to finally minimize the side effects, thus improving the treatment's efficacy. Microfluidics systems are unquestionably a superior technology, which is currently revolutionizing the current chemical and biological studies, providing diminutive chip-scale devices that offer precise dosage, target-precise delivery, and controlled release. Microfluidic systems have emerged as a promising delivery vehicle owing to their potential for defined handling and transporting of small liquid quantities. The latest microfabrication developments have been made for application to several biological systems. Here, we review the fundamentals of microfluidics and their application for local drug delivery.
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Affiliation(s)
- Nimbagal R Naveen
- Department of Pharmaceutics, Sri Adichunchanagiri College of Pharmacy, Adichunchanagiri University, B.G. Nagar, Karnataka 571448, India
| | | | - Prakash S Goudanavar
- Department of Pharmaceutics, Sri Adichunchanagiri College of Pharmacy, Adichunchanagiri University, B.G. Nagar, Karnataka 571448, India
| | - Chagaleti B Kumar
- Department of Pharmaceutical Chemistry, Akshaya Institute of Pharmacy, Lingapura, Tumkur, Karnataka 572106, India
| | - Gunturu L Narasimha
- Department of Pharmacy Practice, Annamacharya College of Pharmacy, New Boyanapalli, Rajampet, India
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16
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McGlynn E, Walton F, Das R, Heidari H. Neural microprobe modelling and microfabrication for improved implantation and mechanical failure mitigation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20210007. [PMID: 35658676 PMCID: PMC9168446 DOI: 10.1098/rsta.2021.0007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Careful design and material selection are the most beneficial strategies to ensure successful implantation and mitigate the failure of a neural probe in the long term. In order to realize a fully flexible implantable system, the probe should be easily manipulated by neuroscientists, with the potential to bend up to 90°. This paper investigates the impact of material choice, probe geometry, and crucially, implantation angle on implantation success through finite-element method simulations in COMSOL Multiphysics followed by cleanroom microfabrication. The designs introduced in this paper were fabricated using two polyimides: (i) PI-2545 as a release layer and (ii) photodefinable HD-4110 as the probe substrate. Four different designs were microfabricated, and the implantation tests were compared between an agarose brain phantom and lamb brain samples. The probes were scanned in a 7 T PharmaScan MRI coil to investigate potential artefacts. From the simulation, a triangular base and 50 µm polymer thickness were identified as the optimum design, which produced a probe 57.7 µm thick when fabricated. The probes exhibit excellent flexibility, exemplified in three-point bending tests performed with a DAGE 4000Plus. Successful implantation is possible for a range of angles between 30° and 90°. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.
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Affiliation(s)
- Eve McGlynn
- Microelectronics Lab (meLAB), James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK
| | - Finlay Walton
- Microelectronics Lab (meLAB), James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK
| | - Rupam Das
- Microelectronics Lab (meLAB), James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK
| | - Hadi Heidari
- Microelectronics Lab (meLAB), James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK
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17
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Akouissi O, Lacour SP, Micera S, DeSimone A. A finite element model of the mechanical interactions between peripheral nerves and intrafascicular implants. J Neural Eng 2022; 19. [PMID: 35861557 DOI: 10.1088/1741-2552/ac7d0e] [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: 07/28/2021] [Accepted: 06/29/2022] [Indexed: 11/11/2022]
Abstract
Objective.Intrafascicular peripheral nerve implants are key components in the development of bidirectional neuroprostheses such as touch-enabled bionic limbs for amputees. However, the durability of such interfaces is hindered by the immune response following the implantation. Among the causes linked to such reaction, the mechanical mismatch between host nerve and implant is thought to play a decisive role, especially in chronic settings.Approach.Here we focus on modeling mechanical stresses induced on the peripheral nerve by the implant's micromotion using finite element analysis. Through multiple parametric sweeps, we analyze the role of the implant's material, geometry (aspect-ratio and shape), and surface coating, deriving a set of parameters for the design of better-integrated implants.Main results.Our results indicate that peripheral nerve implants should be designed and manufactured with smooth edges, using materials at most three orders of magnitude stiffer than the nerve, and with innovative geometries to redistribute micromotion-associated loads to less delicate parts of the nerve such as the epineurium.Significance.Overall, our model is a useful tool for the peripheral nerve implant designer that is mindful of the importance of implant mechanics for long term applications.
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Affiliation(s)
- Outman Akouissi
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Geneva, 1202, Switzerland.,Bertarelli Foundation Chair in Translational Neuroengineering, Translational Neural Engineering Laboratory, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Geneva, 1202, Switzerland
| | - Stéphanie P Lacour
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Geneva, 1202, Switzerland
| | - Silvestro Micera
- Bertarelli Foundation Chair in Translational Neuroengineering, Translational Neural Engineering Laboratory, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Geneva, 1202, Switzerland.,The Biorobotics Institute and Department of Excellence in Robotics & AI, Health Science Interdisciplinary Center, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Antonio DeSimone
- The Biorobotics Institute and Department of Excellence in Robotics & AI, Health Science Interdisciplinary Center, Scuola Superiore Sant'Anna, Pisa, Italy.,SISSA-International School for Advanced Studies, 34136 Trieste, Italy
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18
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Riggins TE, Li W, Purcell EK. Atomic Force Microscope Characterization of the Bending Stiffness and Surface Topography of Silicon and Polymeric Electrodes. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:2348-2352. [PMID: 36085626 DOI: 10.1109/embc48229.2022.9871216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Implanted electrodes in the brain are increasingly used in research and clinical settings to understand and treat neurological conditions. However, a foreign body response typically occurs after implantation, and glial encapsulation of the device is a commonly observed. Multiple factors affect how gliosis surrounding the implantable electrodes evolves. Characterizing and measuring the surface features and mechanical properties of these devices may allow us to predict where gliosis will occur, and understanding how electrode design features may impact astrogliosis may give researchers a set of design guidelines to follow to maximize chronic performance. In this study, we used atomic force microscopy to measure surface roughness on parylene, polyimide, and silicon devices. Multiple features on microelectrode arrays were measured, including electrode sites, traces, and the bulk substrate. We found differences in surface roughness according to device material, but not device features. We also directly measured the bending stiffness of silicon devices, providing a more exact quantification of this property to corroborate calculated estimates.
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19
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Geramifard N, Dousti B, Nguyen CK, Abbott JR, Cogan S, Varner V. Insertion mechanics of amorphous SiC ultra-micro scale neural probes. J Neural Eng 2022; 19. [PMID: 35263724 PMCID: PMC9339220 DOI: 10.1088/1741-2552/ac5bf4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 03/09/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Trauma induced by the insertion of microelectrodes into cortical neural tissue is a significant problem. Further, micromotion and mechanical mismatch between microelectrode probes and neural tissue is implicated in an adverse foreign body response (FBR). Hence, intracortical ultra-microelectrode probes have been proposed as alternatives that minimize this FBR. However, significant challenges in implanting these flexible probes remain. We investigated the insertion mechanics of amorphous silicon carbide (a-SiC) probes with a view to defining probe geometries that can be inserted into cortex without buckling. APPROACH We determined the critical buckling force of a-SiC probes as a function of probe geometry and then characterized the buckling behavior of these probes by measuring force-displacement responses during insertion into agarose gel and rat cortex. MAIN RESULTS Insertion forces for a range of probe geometries were determined and compared with critical buckling forces to establish geometries that should avoid buckling during implantation into brain. The studies show that slower insertion speeds reduce the maximum insertion force for single-shank probes but increase cortical dimpling during insertion of multi-shank probes. SIGNIFICANCE Our results provide a guide for selecting probe geometries and insertion speeds that allow unaided implantation of probes into rat cortex. The design approach is applicable to other animal models where insertion of intracortical probes to a depth of 2 mm is required.
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Affiliation(s)
- Negar Geramifard
- Department of Bioeengineering, The University of Texas at Dallas Erik Jonsson School of Engineering and Computer Science, 800 West Campbell Rd., BSB 13.601, Richardson, Texas, 75080-3021, UNITED STATES
| | - Behnoush Dousti
- The University of Texas at Dallas, Department of Bioengineering, Richardson, Texas, 75080-3021, UNITED STATES
| | - Christopher Khanhtuan Nguyen
- Department of Bioengineering, The University of Texas at Dallas, 800 W Campbell Rd, Richardson, Texas, 75080-3021, UNITED STATES
| | - Justin Robert Abbott
- Department of Bioengineering, The University of Texas at Dallas, 800 West Campbell Rd, Richardson, Texas, 75080, UNITED STATES
| | - Stuart Cogan
- Department of Bioengineering, The University of Texas at Dallas Erik Jonsson School of Engineering and Computer Science, 800 West Campbell Road, Richardson, Texas, 75080-3021, UNITED STATES
| | - Victor Varner
- Department of Bioengineering, The University of Texas at Dallas Erik Jonsson School of Engineering and Computer Science, 800 West Campbell Rd, Richardson, Texas, 75080, UNITED STATES
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20
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Zhao H, Liu R, Zhang H, Cao P, Liu Z, Li Y. Research Progress on the Flexibility of an Implantable Neural Microelectrode. MICROMACHINES 2022; 13:386. [PMID: 35334680 PMCID: PMC8954487 DOI: 10.3390/mi13030386] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 12/25/2021] [Accepted: 01/16/2022] [Indexed: 12/22/2022]
Abstract
Neural microelectrode is the important bridge of information exchange between the human body and machines. By recording and transmitting nerve signals with electrodes, people can control the external machines. At the same time, using electrodes to electrically stimulate nerve tissue, people with long-term brain diseases will be safely and reliably treated. Young's modulus of the traditional rigid electrode probe is not matched well with that of biological tissue, and tissue immune rejection is easy to generate, resulting in the electrode not being able to achieve long-term safety and reliable working. In recent years, the choice of flexible materials and design of electrode structures can achieve modulus matching between electrode and biological tissue, and tissue damage is decreased. This review discusses nerve microelectrodes based on flexible electrode materials and substrate materials. Simultaneously, different structural designs of neural microelectrodes are reviewed. However, flexible electrode probes are difficult to implant into the brain. Only with the aid of certain auxiliary devices, can the implant be safe and reliable. The implantation method of the nerve microelectrode is also reviewed.
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Affiliation(s)
- Huiqing Zhao
- Beijing Institute of Graphic Communication, Beijing 102600, China
| | - Ruping Liu
- Beijing Institute of Graphic Communication, Beijing 102600, China
| | - Huiling Zhang
- Beijing Institute of Graphic Communication, Beijing 102600, China
| | - Peng Cao
- Beijing Institute of Graphic Communication, Beijing 102600, China
| | - Zilong Liu
- Division of Optics, National Institute of Metrology, Beijing 100029, China
| | - Ye Li
- Beijing Institute of Graphic Communication, Beijing 102600, China
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21
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Abstract
![]()
Electronically interfacing with the
nervous system for the purposes
of health diagnostics and therapy, sports performance monitoring,
or device control has been a subject of intense academic and industrial
research for decades. This trend has only increased in recent years,
with numerous high-profile research initiatives and commercial endeavors.
An important research theme has emerged as a result, which is the
incorporation of semiconducting polymers in various devices that communicate
with the nervous system—from wearable brain-monitoring caps
to penetrating implantable microelectrodes. This has been driven by
the potential of this broad class of materials to improve the electrical
and mechanical properties of the tissue–device interface, along
with possibilities for increased biocompatibility. In this review
we first begin with a tutorial on neural interfacing, by reviewing
the basics of nervous system function, device physics, and neuroelectrophysiological
techniques and their demands, and finally we give a brief perspective
on how material improvements can address current deficiencies in this
system. The second part is a detailed review of past work on semiconducting
polymers, covering electrical properties, structure, synthesis, and
processing.
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Affiliation(s)
- Ivan B Dimov
- Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, U.K
| | - Maximilian Moser
- University of Oxford, Department of Chemistry, Oxford OX1 3TA, United Kingdom
| | - George G Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, U.K
| | - Iain McCulloch
- University of Oxford, Department of Chemistry, Oxford OX1 3TA, United Kingdom.,King Abdullah University of Science and Technology (KAUST), KAUST Solar Center, Thuwal 23955-6900, Saudi Arabia
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22
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Vėbraitė I, Hanein Y. Soft Devices for High-Resolution Neuro-Stimulation: The Interplay Between Low-Rigidity and Resolution. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:675744. [PMID: 35047928 PMCID: PMC8757739 DOI: 10.3389/fmedt.2021.675744] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/14/2021] [Indexed: 12/27/2022] Open
Abstract
The field of neurostimulation has evolved over the last few decades from a crude, low-resolution approach to a highly sophisticated methodology entailing the use of state-of-the-art technologies. Neurostimulation has been tested for a growing number of neurological applications, demonstrating great promise and attracting growing attention in both academia and industry. Despite tremendous progress, long-term stability of the implants, their large dimensions, their rigidity and the methods of their introduction and anchoring to sensitive neural tissue remain challenging. The purpose of this review is to provide a concise introduction to the field of high-resolution neurostimulation from a technological perspective and to focus on opportunities stemming from developments in materials sciences and engineering to reduce device rigidity while optimizing electrode small dimensions. We discuss how these factors may contribute to smaller, lighter, softer and higher electrode density devices.
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Affiliation(s)
- Ieva Vėbraitė
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Yael Hanein
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
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23
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Otte E, Vlachos A, Asplund M. Engineering strategies towards overcoming bleeding and glial scar formation around neural probes. Cell Tissue Res 2022; 387:461-477. [PMID: 35029757 PMCID: PMC8975777 DOI: 10.1007/s00441-021-03567-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/17/2021] [Indexed: 12/15/2022]
Abstract
Neural probes are sophisticated electrophysiological tools used for intra-cortical recording and stimulation. These microelectrode arrays, designed to penetrate and interface the brain from within, contribute at the forefront of basic and clinical neuroscience. However, one of the challenges and currently most significant limitations is their ‘seamless’ long-term integration into the surrounding brain tissue. Following implantation, which is typically accompanied by bleeding, the tissue responds with a scarring process, resulting in a gliotic region closest to the probe. This glial scarring is often associated with neuroinflammation, neurodegeneration, and a leaky blood–brain interface (BBI). The engineering progress on minimizing this reaction in the form of improved materials, microfabrication, and surgical techniques is summarized in this review. As research over the past decade has progressed towards a more detailed understanding of the nature of this biological response, it is time to pose the question: Are penetrating probes completely free from glial scarring at all possible?
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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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Sharafkhani N, Kouzani AZ, Adams SD, Long JM, Lissorgues G, Rousseau L, Orwa JO. Neural tissue-microelectrode interaction: Brain micromotion, electrical impedance, and flexible microelectrode insertion. J Neurosci Methods 2022; 365:109388. [PMID: 34678387 DOI: 10.1016/j.jneumeth.2021.109388] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 10/17/2021] [Accepted: 10/17/2021] [Indexed: 10/20/2022]
Abstract
Insertion of a microelectrode into the brain to record/stimulate neurons damages neural tissue and blood vessels and initiates the brain's wound healing response. Due to the large difference between the stiffness of neural tissue and microelectrode, brain micromotion also leads to neural tissue damage and associated local immune response. Over time, following implantation, the brain's response to the tissue damage can result in microelectrode failure. Reducing the microelectrode's cross-sectional dimensions to single-digit microns or using soft materials with elastic modulus close to that of the neural tissue are effective methods to alleviate the neural tissue damage and enhance microelectrode longevity. However, the increase in electrical impedance of the microelectrode caused by reducing the microelectrode contact site's dimensions can decrease the signal-to-noise ratio. Most importantly, the reduced dimensions also lead to a reduction in the critical buckling force, which increases the microelectrode's propensity to buckling during insertion. After discussing brain micromotion, the main source of neural tissue damage, surface modification of the microelectrode contact site is reviewed as a key method for addressing the increase in electrical impedance issue. The review then focuses on recent approaches to aiding insertion of flexible microelectrodes into the brain, including bending stiffness modification, effective length reduction, and application of a magnetic field to pull the electrode. An understanding of the advantages and drawbacks of the developed strategies offers a guide for dealing with the buckling phenomenon during implantation.
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Affiliation(s)
- Naser Sharafkhani
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia.
| | - Abbas Z Kouzani
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia
| | - Scott D Adams
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia
| | - John M Long
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia
| | | | | | - Julius O Orwa
- School of Engineering, Deakin University, Geelong, VIC 3216, Australia.
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Rommelfanger NJ, Keck CH, Chen Y, Hong G. Learning from the brain's architecture: bioinspired strategies towards implantable neural interfaces. Curr Opin Biotechnol 2021; 72:8-12. [PMID: 34365114 PMCID: PMC8671194 DOI: 10.1016/j.copbio.2021.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 07/15/2021] [Accepted: 07/17/2021] [Indexed: 11/16/2022]
Abstract
While early neural interfaces consisted of rigid, monolithic probes, recent implantable technologies include meshes, gels, and threads that imitate various properties of the neural tissue itself. Such mimicry brings new capabilities to the traditional electrophysiology toolbox, with benefits for both neuroscience studies and clinical treatments. Specifically, by matching the multi-dimensional mechanical properties of the brain, neural implants can preserve the endogenous environment while functioning over chronic timescales. Further, topological mimicry of neural structures enables seamless integration into the tissue and provides proximal access to neurons for high-quality recordings. Ultimately, we envision that neuromorphic devices incorporating functional, mechanical, and topological mimicry of the brain may facilitate stable operation of advanced brain machine interfaces with minimal disruption of the native tissue.
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Affiliation(s)
- Nicholas J Rommelfanger
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA; Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
| | - Carl Hc Keck
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA; Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
| | - Yihang Chen
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA; Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA
| | - Guosong Hong
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA; Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA 94305, USA.
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Ahmed Z, Reddy JW, Malekoshoaraie MH, Hassanzade V, Kimukin I, Jain V, Chamanzar M. Flexible optoelectric neural interfaces. Curr Opin Biotechnol 2021; 72:121-130. [PMID: 34826682 PMCID: PMC9741731 DOI: 10.1016/j.copbio.2021.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 10/30/2021] [Accepted: 11/02/2021] [Indexed: 12/14/2022]
Abstract
Understanding the neural basis of brain function and dysfunction and designing effective therapeutics require high resolution targeted stimulation and recording of neural activity. Optical methods have been recently developed for neural stimulation as well as functional and structural imaging. These methods call for implantable devices to deliver light into the neural tissue at depth with high spatiotemporal resolution. To address this need, rigid and flexible neurophotonic implants have been recently designed. This article reviews the state-of-the-art flexible passive and active penetrating optical neural probes developed for light delivery with minimal damage to the tissue. Passive and active flexible neurophotonic implants are compared and insights about future directions are provided.
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Cho YH, Park YG, Kim S, Park JU. 3D Electrodes for Bioelectronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2005805. [PMID: 34013548 DOI: 10.1002/adma.202005805] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/04/2020] [Indexed: 05/08/2023]
Abstract
In recent studies related to bioelectronics, significant efforts have been made to form 3D electrodes to increase the effective surface area or to optimize the transfer of signals at tissue-electrode interfaces. Although bioelectronic devices with 2D and flat electrode structures have been used extensively for monitoring biological signals, these 2D planar electrodes have made it difficult to form biocompatible and uniform interfaces with nonplanar and soft biological systems (at the cellular or tissue levels). Especially, recent biomedical applications have been expanding rapidly toward 3D organoids and the deep tissues of living animals, and 3D bioelectrodes are getting significant attention because they can reach the deep regions of various 3D tissues. An overview of recent studies on 3D bioelectronic devices, such as the use of electrical stimulations and the recording of neural signals from biological subjects, is presented. Subsequently, the recent developments in materials and fabrication processing to 3D micro- and nanostructures are introduced, followed by broad applications of these 3D bioelectronic devices at various in vitro and in vivo conditions.
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Affiliation(s)
- Yo Han Cho
- Nano Science Technology Institute, Department of Materials Science and Engineering, Yonsei University, Seoul, 03722, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul, 03722, Republic of Korea
- Graduate Program of Nano Biomedical Engineering (NanoBME), Advanced Science Institute, Yonsei University, Seoul, 03722, Republic of Korea
| | - Young-Geun Park
- Nano Science Technology Institute, Department of Materials Science and Engineering, Yonsei University, Seoul, 03722, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul, 03722, Republic of Korea
- Graduate Program of Nano Biomedical Engineering (NanoBME), Advanced Science Institute, Yonsei University, Seoul, 03722, Republic of Korea
| | - Sumin Kim
- Nano Science Technology Institute, Department of Materials Science and Engineering, Yonsei University, Seoul, 03722, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul, 03722, Republic of Korea
- Graduate Program of Nano Biomedical Engineering (NanoBME), Advanced Science Institute, Yonsei University, Seoul, 03722, Republic of Korea
| | - Jang-Ung Park
- Nano Science Technology Institute, Department of Materials Science and Engineering, Yonsei University, Seoul, 03722, Republic of Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul, 03722, Republic of Korea
- Graduate Program of Nano Biomedical Engineering (NanoBME), Advanced Science Institute, Yonsei University, Seoul, 03722, Republic of Korea
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Kumosa LS, Schouenborg J. Profound alterations in brain tissue linked to hypoxic episode after device implantation. Biomaterials 2021; 278:121143. [PMID: 34653937 DOI: 10.1016/j.biomaterials.2021.121143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 09/20/2021] [Indexed: 12/17/2022]
Abstract
To enable authentic interfacing with neuronal structures in the brain, preventing alterations of tissue during implantation of devices is critical. By transiently implanting oxygen microsensors into rat cortex cerebri for 2 h, substantial and long lasting (>1 h) hypoxia is routinely generated in surrounding tissues; this hypoxia is linked to implantation generated compressive forces. Preferential loss of larger neurons and reduced metabolic components in surviving neurons indicates decreased viability one week after such hypoxic, compressive implantations. By devising an implantation method that relaxes compressive forces; magnitude and duration of hypoxia generated following such an implantation are ameliorated and neurons appear similar to naïve tissues. In line with these observations, astrocyte proliferation was significantly more pronounced for more hypoxic, compressive implantations. Surprisingly, astrocyte processes were frequently found to traverse cellular boundaries into nearby neuronal nuclei, indicating injury induction of a previously not described astrocyte-neuron interaction. Found more frequently in less hypoxic, force-relaxed insertions and thus correlating to a more beneficial outcome, this finding may suggest a novel protective mechanism. In conclusion, substantial and long lasting insertion induced hypoxia around brain implants, a previously overlooked factor, is linked to significant adverse alterations in nervous tissue.
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Affiliation(s)
- Lucas S Kumosa
- Neuronano Research Center, Faculty of Medicine, Lund University, Scheelevägen 2, Medicon Village 404A2, 223 81, Lund, Sweden.
| | - Jens Schouenborg
- Neuronano Research Center, Faculty of Medicine, Lund University, Scheelevägen 2, Medicon Village 404A2, 223 81, Lund, Sweden; NanoLund, Lund University, Professorsgatan 1, 223 63, Lund, Sweden.
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Srikantharajah K, Medinaceli Quintela R, Doerenkamp K, Kampa BM, Musall S, Rothermel M, Offenhäusser A. Minimally-invasive insertion strategy and in vivo evaluation of multi-shank flexible intracortical probes. Sci Rep 2021; 11:18920. [PMID: 34556704 PMCID: PMC8460634 DOI: 10.1038/s41598-021-97940-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 08/26/2021] [Indexed: 11/16/2022] Open
Abstract
Chronically implanted neural probes are powerful tools to decode brain activity however, recording population and spiking activity over long periods remains a major challenge. Here, we designed and fabricated flexible intracortical Michigan-style arrays with a shank cross-section per electrode of 250 μm[Formula: see text] utilizing the polymer paryleneC with the goal to improve the immune acceptance. As flexible neural probes are unable to penetrate the brain due to the low buckling force threshold, a tissue-friendly insertion system was developed by reducing the effective shank length. The insertion strategy enabled the implantation of the four, bare, flexible shanks up to 2 mm into the mouse brain without increasing the implantation footprint and therefore, minimizing the acute trauma. In acute recordings from the mouse somatosensory cortex and the olfactory bulb, we demonstrated that the flexible probes were able to simultaneously detect local field potentials as well as single and multi-unit activity. Additionally, the flexible arrays outperformed stiff probes with respect to yield of single unit activity. Following the successful in vivo validation, we further improved the microfabrication towards a double-metal-layer process, and were able to double the number of electrodes per shank by keeping the shank width resulting in a cross-section per electrode of 118 μm[Formula: see text].
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Affiliation(s)
- Kagithiri Srikantharajah
- Bioelectronics, Institute of Biological Information Processing-3, Forschungszentrum Jülich, Jülich, Germany
- RWTH Aachen University, Aachen, Germany
| | - Renata Medinaceli Quintela
- Institute for Physiology and Cell Biology, University of Veterinary Medicine, Foundation, Hannover, Germany
| | - Kerstin Doerenkamp
- Department of Neurophysiology, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Björn M Kampa
- Department of Neurophysiology, Institute for Biology II, RWTH Aachen University, Aachen, Germany
- JARA BRAIN, Institute for Neuroscience and Medicine, Forschungszentrum Jülich, Jülich, Germany
| | - Simon Musall
- Bioelectronics, Institute of Biological Information Processing-3, Forschungszentrum Jülich, Jülich, Germany
| | - Markus Rothermel
- Institute for Physiology and Cell Biology, University of Veterinary Medicine, Foundation, Hannover, Germany
| | - Andreas Offenhäusser
- Bioelectronics, Institute of Biological Information Processing-3, Forschungszentrum Jülich, Jülich, Germany.
- RWTH Aachen University, Aachen, Germany.
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31
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Intracortical Microelectrode Array Unit Yield under Chronic Conditions: A Comparative Evaluation. MICROMACHINES 2021; 12:mi12080972. [PMID: 34442594 PMCID: PMC8400387 DOI: 10.3390/mi12080972] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 01/01/2023]
Abstract
While microelectrode arrays (MEAs) offer the promise of elucidating functional neural circuitry and serve as the basis for a cortical neuroprosthesis, the challenge of designing and demonstrating chronically reliable technology remains. Numerous studies report “chronic” data but the actual time spans and performance measures corresponding to the experimental work vary. In this study, we reviewed the experimental durations that constitute chronic studies across a range of MEA types and animal species to gain an understanding of the widespread variability in reported study duration. For rodents, which are the most commonly used animal model in chronic studies, we examined active electrode yield (AEY) for different array types as a means to contextualize the study duration variance, as well as investigate and interpret the performance of custom devices in comparison to conventional MEAs. We observed wide-spread variance within species for the chronic implantation period and an AEY that decayed linearly in rodent models that implanted commercially-available devices. These observations provide a benchmark for comparing the performance of new technologies and highlight the need for consistency in chronic MEA studies. Additionally, to fully derive performance under chronic conditions, the duration of abiotic failure modes, biological processes induced by indwelling probes, and intended application of the device are key determinants.
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Liu X, Bibineyshvili Y, Robles DA, Boreland AJ, Margolis DJ, Shreiber DI, Zahn JD. Fabrication of a Multilayer Implantable Cortical Microelectrode Probe to Improve Recording Potential. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS : A JOINT IEEE AND ASME PUBLICATION ON MICROSTRUCTURES, MICROACTUATORS, MICROSENSORS, AND MICROSYSTEMS 2021; 30:569-581. [PMID: 34539168 PMCID: PMC8445332 DOI: 10.1109/jmems.2021.3092230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Intracortical neural probes are a key enabling technology for acquiring high fidelity neural signals within the cortex. They are viewed as a crucial component of brain-computer interfaces (BCIs) in order to record electrical activities from neurons within the brain. Smaller, more flexible, polymer-based probes have been investigated for their potential to limit the acute and chronic neural tissue response. Conventional methods of patterning electrodes and connecting traces on a single supporting layer can limit the number of recording sites which can be defined, particularly when designing narrower probes. We present a novel strategy of increasing the number of recording sites without proportionally increasing the size of the probe by using a multilayer fabrication process to vertically layer recording traces on multiple Parylene support layers, allowing more recording traces to be defined on a smaller probe width. Using this approach, we are able to define 16 electrodes on 4 supporting layers (4 electrodes per layer), each with a 30 μm diameter recording window and 5 μm wide connecting trace defined by conventional LWUV lithography, on an 80 μm wide by 9 μm thick microprobe. Prior to in vitro and in vivo validation, the multilayer probes are electrically characterized via impedance spectroscopy and evaluating crosstalk between adjacent layers. Demonstration of acute in vitro recordings in a cerebral organoid model and in vivo recordings in a murine model indicate the probe's capability for single unit recordings. This work demonstrates the ability to fabricate smaller, more compliant neural probes without sacrificing electrode density.
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Affiliation(s)
- Xin Liu
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
| | - Yelena Bibineyshvili
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA
| | - Denise A Robles
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
| | - Andrew J Boreland
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA
| | - David J Margolis
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854 USA
| | - David I Shreiber
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
| | - Jeffrey D Zahn
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854 USA
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Sridharan A, Muthuswamy J. Soft, Conductive, Brain-Like, Coatings at Tips of Microelectrodes Improve Electrical Stability under Chronic, In Vivo Conditions. MICROMACHINES 2021; 12:761. [PMID: 34203234 PMCID: PMC8306035 DOI: 10.3390/mi12070761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/22/2021] [Accepted: 06/25/2021] [Indexed: 01/27/2023]
Abstract
Several recent studies have reported improved histological and electrophysiological outcomes with soft neural interfaces that have elastic moduli ranging from 10 s of kPa to hundreds of MPa. However, many of these soft interfaces use custom fabrication processes. We test the hypothesis that a readily adoptable fabrication process for only coating the tips of microelectrodes with soft brain-like (elastic modulus of ~5 kPa) material improves the long-term electrical performance of neural interfaces. Conventional tungsten microelectrodes (n = 9 with soft coatings and n = 6 uncoated controls) and Pt/Ir microelectrodes (n = 16 with soft coatings) were implanted in six animals for durations ranging from 5 weeks to over 1 year in a subset of rats. Electrochemical impedance spectroscopy was used to assess the quality of the brain tissue-electrode interface under chronic conditions. Neural recordings were assessed for unit activity and signal quality. Electrodes with soft, silicone coatings showed relatively stable electrical impedance characteristics over 6 weeks to >1 year compared to the uncoated control electrodes. Single unit activity recorded by coated electrodes showed larger peak-to-peak amplitudes and increased number of detectable neurons compared to uncoated controls over 6-7 weeks. We demonstrate the feasibility of using a readily translatable process to create brain-like soft interfaces that can potentially overcome variable performance associated with chronic rigid neural interfaces.
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Affiliation(s)
| | - Jit Muthuswamy
- School of Biological and Health Systems Engineering, Ira A. Fulton School of Engineering, Arizona State University, Tempe, AZ 85287-9709, USA;
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Park S, Yuk H, Zhao R, Yim YS, Woldeghebriel EW, Kang J, Canales A, Fink Y, Choi GB, Zhao X, Anikeeva P. Adaptive and multifunctional hydrogel hybrid probes for long-term sensing and modulation of neural activity. Nat Commun 2021; 12:3435. [PMID: 34103511 PMCID: PMC8187649 DOI: 10.1038/s41467-021-23802-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Accepted: 05/18/2021] [Indexed: 11/20/2022] Open
Abstract
To understand the underlying mechanisms of progressive neurophysiological phenomena, neural interfaces should interact bi-directionally with brain circuits over extended periods of time. However, such interfaces remain limited by the foreign body response that stems from the chemo-mechanical mismatch between the probes and the neural tissues. To address this challenge, we developed a multifunctional sensing and actuation platform consisting of multimaterial fibers intimately integrated within a soft hydrogel matrix mimicking the brain tissue. These hybrid devices possess adaptive bending stiffness determined by the hydration states of the hydrogel matrix. This enables their direct insertion into the deep brain regions, while minimizing tissue damage associated with the brain micromotion after implantation. The hydrogel hybrid devices permit electrophysiological, optogenetic, and behavioral studies of neural circuits with minimal foreign body responses and tracking of stable isolated single neuron potentials in freely moving mice over 6 months following implantation.
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Affiliation(s)
- Seongjun Park
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- KAIST Institute for Health and Science Technology (KIHST), Daejeon, Republic of Korea
| | - Hyunwoo Yuk
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ruike Zhao
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, USA
| | - Yeong Shin Yim
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Eyob W Woldeghebriel
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jeewoo Kang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Andres Canales
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Material Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yoel Fink
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Material Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gloria B Choi
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Xuanhe Zhao
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Polina Anikeeva
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Material Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
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35
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Redolfi Riva E, Micera S. Progress and challenges of implantable neural interfaces based on nature-derived materials. Bioelectron Med 2021; 7:6. [PMID: 33902750 PMCID: PMC8077843 DOI: 10.1186/s42234-021-00067-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/31/2021] [Indexed: 12/31/2022] Open
Abstract
Neural interfaces are bioelectronic devices capable of stimulating a population of neurons or nerve fascicles and recording electrical signals in a specific area. Despite their success in restoring sensory-motor functions in people with disabilities, their long-term exploitation is still limited by poor biocompatibility, mechanical mismatch between the device and neural tissue and the risk of a chronic inflammatory response upon implantation.In this context, the use of nature-derived materials can help address these issues. Examples of these materials, such as extracellular matrix proteins, peptides, lipids and polysaccharides, have been employed for decades in biomedical science. Their excellent biocompatibility, biodegradability in the absence of toxic compound release, physiochemical properties that are similar to those of human tissues and reduced immunogenicity make them outstanding candidates to improve neural interface biocompatibility and long-term implantation safety. The objective of this review is to highlight progress and challenges concerning the impact of nature-derived materials on neural interface design. The use of these materials as biocompatible coatings and as building blocks of insulation materials for use in implantable neural interfaces is discussed. Moreover, future perspectives are presented to show the increasingly important uses of these materials for neural interface fabrication and their possible use for other applications in the framework of neural engineering.
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Affiliation(s)
- Eugenio Redolfi Riva
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy.
| | - Silvestro Micera
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
- Bertarelli Foundation Chair in Translational Neuroengineering, Centre for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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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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Dubaniewicz M, Eles JR, Lam S, Song S, Cambi F, Sun D, Wellman SM, Kozai TDY. Inhibition of Na +/H +exchanger modulates microglial activation and scar formation following microelectrode implantation. J Neural Eng 2021; 18. [PMID: 33621208 DOI: 10.1088/1741-2552/abe8f1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/23/2021] [Indexed: 11/12/2022]
Abstract
Objective.Intracortical microelectrodes are an important tool for neuroscience research and have great potential for clinical use. However, the use of microelectrode arrays to treat neurological disorders and control prosthetics is limited by biological challenges such as glial scarring, which can impair chronic recording performance. Microglia activation is an early and prominent contributor to glial scarring. After insertion of an intracortical microelectrode, nearby microglia transition into a state of activation, migrate, and encapsulate the device. Na+/H+exchanger isoform-1 (NHE-1) is involved in various microglial functions, including their polarity and motility, and has been implicated in pro-inflammatory responses to tissue injury. HOE-642 (cariporide) is an inhibitor of NHE-1 and has been shown to depress microglial activation and inflammatory response in brain injury models.Approach.In this study, the effects of HOE-642 treatment on microglial interactions to intracortical microelectrodes was evaluated using two-photon microscopyin vivo.Main results.The rate at which microglia processes and soma migrate in response to electrode implantation was unaffected by HOE-642 administration. However, HOE-642 administration effectively reduced the radius of microglia activation at 72 h post-implantation from 222.2µm to 177.9µm. Furthermore, treatment with HOE-642 significantly reduced microglial encapsulation of implanted devices at 5 h post-insertion from 50.7 ± 6.0% to 8.9 ± 6.1%, which suggests an NHE-1-specific mechanism mediating microglia reactivity and gliosis during implantation injury.Significance.This study implicates NHE-1 as a potential target of interest in microglial reactivity and HOE-642 as a potential treatment to attenuate the glial response and scar formation around implanted intracortical microelectrodes.
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Affiliation(s)
- Mitchell Dubaniewicz
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Stephanie Lam
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Shanshan Song
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Franca Cambi
- Veterans Administration Pittsburgh, Pittsburgh, PA, United States of America.,Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Dandan Sun
- Veterans Administration Pittsburgh, Pittsburgh, PA, United States of America.,Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, United States of America.,Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America.,McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America.,NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
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Purcell EK, Becker MF, Guo Y, Hara SA, Ludwig KA, McKinney CJ, Monroe EM, Rechenberg R, Rusinek CA, Saxena A, Siegenthaler JR, Sortwell CE, Thompson CH, Trevathan JK, Witt S, Li W. Next-Generation Diamond Electrodes for Neurochemical Sensing: Challenges and Opportunities. MICROMACHINES 2021; 12:128. [PMID: 33530395 PMCID: PMC7911340 DOI: 10.3390/mi12020128] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/19/2021] [Accepted: 01/19/2021] [Indexed: 12/12/2022]
Abstract
Carbon-based electrodes combined with fast-scan cyclic voltammetry (FSCV) enable neurochemical sensing with high spatiotemporal resolution and sensitivity. While their attractive electrochemical and conductive properties have established a long history of use in the detection of neurotransmitters both in vitro and in vivo, carbon fiber microelectrodes (CFMEs) also have limitations in their fabrication, flexibility, and chronic stability. Diamond is a form of carbon with a more rigid bonding structure (sp3-hybridized) which can become conductive when boron-doped. Boron-doped diamond (BDD) is characterized by an extremely wide potential window, low background current, and good biocompatibility. Additionally, methods for processing and patterning diamond allow for high-throughput batch fabrication and customization of electrode arrays with unique architectures. While tradeoffs in sensitivity can undermine the advantages of BDD as a neurochemical sensor, there are numerous untapped opportunities to further improve performance, including anodic pretreatment, or optimization of the FSCV waveform, instrumentation, sp2/sp3 character, doping, surface characteristics, and signal processing. Here, we review the state-of-the-art in diamond electrodes for neurochemical sensing and discuss potential opportunities for future advancements of the technology. We highlight our team's progress with the development of an all-diamond fiber ultramicroelectrode as a novel approach to advance the performance and applications of diamond-based neurochemical sensors.
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Affiliation(s)
- Erin K. Purcell
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA; (Y.G.); (A.S.); (W.L.)
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, USA;
- Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA;
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Michael F. Becker
- Fraunhofer USA Center Midwest, East Lansing, MI 48824, USA; (M.F.B.); (R.R.); (J.R.S.); (S.W.)
| | - Yue Guo
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA; (Y.G.); (A.S.); (W.L.)
| | - Seth A. Hara
- Division of Engineering, Mayo Clinic, Rochester, MN 55905, USA;
| | - Kip A. Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; (K.A.L.); (J.K.T.)
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Collin J. McKinney
- Department of Chemistry, Electronics Core Facility, University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA;
| | - Elizabeth M. Monroe
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154, USA; (E.M.M.); (C.A.R.)
| | - Robert Rechenberg
- Fraunhofer USA Center Midwest, East Lansing, MI 48824, USA; (M.F.B.); (R.R.); (J.R.S.); (S.W.)
| | - Cory A. Rusinek
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154, USA; (E.M.M.); (C.A.R.)
| | - Akash Saxena
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA; (Y.G.); (A.S.); (W.L.)
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - James R. Siegenthaler
- Fraunhofer USA Center Midwest, East Lansing, MI 48824, USA; (M.F.B.); (R.R.); (J.R.S.); (S.W.)
| | - Caryl E. Sortwell
- Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA;
- Department of Translational Neuroscience, College of Human Medicine, Michigan State University, Grand Rapids, MI 49503, USA
| | - Cort H. Thompson
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, USA;
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - James K. Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; (K.A.L.); (J.K.T.)
- Grainger Institute for Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Suzanne Witt
- Fraunhofer USA Center Midwest, East Lansing, MI 48824, USA; (M.F.B.); (R.R.); (J.R.S.); (S.W.)
| | - Wen Li
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA; (Y.G.); (A.S.); (W.L.)
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI 48824, USA;
- Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA;
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
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Maiolo L, Guarino V, Saracino E, Convertino A, Melucci M, Muccini M, Ambrosio L, Zamboni R, Benfenati V. Glial Interfaces: Advanced Materials and Devices to Uncover the Role of Astroglial Cells in Brain Function and Dysfunction. Adv Healthc Mater 2021; 10:e2001268. [PMID: 33103375 DOI: 10.1002/adhm.202001268] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 10/06/2020] [Indexed: 12/13/2022]
Abstract
Research over the past four decades has highlighted the importance of certain brain cells, called glial cells, and has moved the neurocentric vision of structure, function, and pathology of the nervous system toward a more holistic perspective. In this view, the demand for technologies that are able to target and both selectively monitor and control glial cells is emerging as a challenge across neuroscience, engineering, chemistry, and material science. Frequently neglected or marginally considered as a barrier to be overcome between neural implants and neuronal targets, glial cells, and in particular astrocytes, are increasingly considered as active players in determining the outcomes of device implantation. This review provides a concise overview not only of the previously established but also of the emerging physiological and pathological roles of astrocytes. It also critically discusses the most recent advances in biomaterial interfaces and devices that interact with glial cells and thus have enabled scientists to reach unprecedented insights into the role of astroglial cells in brain function and dysfunction. This work proposes glial interfaces and glial engineering as multidisciplinary fields that have the potential to enable significant advancement of knowledge surrounding cognitive function and acute and chronic neuropathologies.
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Affiliation(s)
- Luca Maiolo
- Consiglio Nazionale delle Ricerche Istituto per la Microelettronica e i Microsistemi Via del Fosso del Cavaliere n.100 Roma 00133 Italy
| | - Vincenzo Guarino
- Consiglio Nazionale delle Ricerche Istituto per i Polimeri Compositi e Biomateriali Viale J.F. Kennedy 54, Mostra d'Oltremare, Pad 20 Napoli 80125 Italy
| | - Emanuela Saracino
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
| | - Annalisa Convertino
- Consiglio Nazionale delle Ricerche Istituto per la Microelettronica e i Microsistemi Via del Fosso del Cavaliere n.100 Roma 00133 Italy
| | - Manuela Melucci
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
| | - Michele Muccini
- Consiglio Nazionale delle Ricerche Istituto per la Studio dei Materiali Nanostrutturati via P. Gobetti 101 Bologna 40129 Italy
| | - Luigi Ambrosio
- Consiglio Nazionale delle Ricerche Istituto per i Polimeri Compositi e Biomateriali Viale J.F. Kennedy 54, Mostra d'Oltremare, Pad 20 Napoli 80125 Italy
| | - Roberto Zamboni
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
| | - Valentina Benfenati
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
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40
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Vandekerckhove B, Missinne J, Vonck K, Bauwens P, Verplancke R, Boon P, Raedt R, Vanfleteren J. Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain. MICROMACHINES 2020; 12:38. [PMID: 33396287 PMCID: PMC7824489 DOI: 10.3390/mi12010038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/24/2020] [Accepted: 12/28/2020] [Indexed: 12/25/2022]
Abstract
Epilepsy is a chronic, neurological disorder affecting millions of people every year. The current available pharmacological and surgical treatments are lacking in overall efficacy and cause side-effects like cognitive impairment, depression, tremor, abnormal liver and kidney function. In recent years, the application of optogenetic implants have shown promise to target aberrant neuronal circuits in epilepsy with the advantage of both high spatial and temporal resolution and high cell-specificity, a feature that could tackle both the efficacy and side-effect problems in epilepsy treatment. Optrodes consist of electrodes to record local field potentials and an optical component to modulate neurons via activation of opsin expressed by these neurons. The goal of optogenetics in epilepsy is to interrupt seizure activity in its earliest state, providing a so-called closed-loop therapeutic intervention. The chronic implantation in vivo poses specific demands for the engineering of therapeutic optrodes. Enzymatic degradation and glial encapsulation of implants may compromise long-term recording and sufficient illumination of the opsin-expressing neural tissue. Engineering efforts for optimal optrode design have to be directed towards limitation of the foreign body reaction by reducing the implant's elastic modulus and overall size, while still providing stable long-term recording and large-area illumination, and guaranteeing successful intracerebral implantation. This paper presents an overview of the challenges and recent advances in the field of electrode design, neural-tissue illumination, and neural-probe implantation, with the goal of identifying a suitable candidate to be incorporated in a therapeutic approach for long-term treatment of epilepsy patients.
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Affiliation(s)
- Bram Vandekerckhove
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Jeroen Missinne
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Kristl Vonck
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Pieter Bauwens
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Rik Verplancke
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Paul Boon
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Robrecht Raedt
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Jan Vanfleteren
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
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Luan L, Robinson JT, Aazhang B, Chi T, Yang K, Li X, Rathore H, Singer A, Yellapantula S, Fan Y, Yu Z, Xie C. Recent Advances in Electrical Neural Interface Engineering: Minimal Invasiveness, Longevity, and Scalability. Neuron 2020; 108:302-321. [PMID: 33120025 PMCID: PMC7646678 DOI: 10.1016/j.neuron.2020.10.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 10/03/2020] [Accepted: 10/08/2020] [Indexed: 12/16/2022]
Abstract
Electrical neural interfaces serve as direct communication pathways that connect the nervous system with the external world. Technological advances in this domain are providing increasingly more powerful tools to study, restore, and augment neural functions. Yet, the complexities of the nervous system give rise to substantial challenges in the design, fabrication, and system-level integration of these functional devices. In this review, we present snapshots of the latest progresses in electrical neural interfaces, with an emphasis on advances that expand the spatiotemporal resolution and extent of mapping and manipulating brain circuits. We include discussions of large-scale, long-lasting neural recording; wireless, miniaturized implants; signal transmission, amplification, and processing; as well as the integration of interfaces with optical modalities. We outline the background and rationale of these developments and share insights into the future directions and new opportunities they enable.
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Affiliation(s)
- Lan Luan
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA; Department of Bioengineering, Rice University, Houston, TX, USA; NeuroEngineering Initiative, Rice University, Houston, TX, USA
| | - Jacob T Robinson
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA; Department of Bioengineering, Rice University, Houston, TX, USA; NeuroEngineering Initiative, Rice University, Houston, TX, USA
| | - Behnaam Aazhang
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA; NeuroEngineering Initiative, Rice University, Houston, TX, USA
| | - Taiyun Chi
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Kaiyuan Yang
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Xue Li
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA; NeuroEngineering Initiative, Rice University, Houston, TX, USA
| | - Haad Rathore
- NeuroEngineering Initiative, Rice University, Houston, TX, USA; Applied Physics Graduate Program, Rice University, Houston, TX, USA
| | - Amanda Singer
- NeuroEngineering Initiative, Rice University, Houston, TX, USA; Applied Physics Graduate Program, Rice University, Houston, TX, USA
| | - Sudha Yellapantula
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA; NeuroEngineering Initiative, Rice University, Houston, TX, USA
| | - Yingying Fan
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Zhanghao Yu
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA; Department of Bioengineering, Rice University, Houston, TX, USA; NeuroEngineering Initiative, Rice University, Houston, TX, USA.
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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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Woods GA, Rommelfanger NJ, Hong G. Bioinspired Materials for In Vivo Bioelectronic Neural Interfaces. MATTER 2020; 3:1087-1113. [PMID: 33103115 PMCID: PMC7583599 DOI: 10.1016/j.matt.2020.08.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The success of in vivo neural interfaces relies on their long-term stability and large scale in interrogating and manipulating neural activity after implantation. Conventional neural probes, owing to their limited spatiotemporal resolution and scale, face challenges for studying the massive, interconnected neural network in its native state. In this review, we argue that taking inspiration from biology will unlock the next generation of in vivo bioelectronic neural interfaces. Reducing the feature sizes of bioelectronic neural interfaces to mimic those of neurons enables high spatial resolution and multiplexity. Additionally, chronic stability at the device-tissue interface is realized by matching the mechanical properties of bioelectronic neural interfaces to those of the endogenous tissue. Further, modeling the design of neural interfaces after the endogenous topology of the neural circuitry enables new insights into the connectivity and dynamics of the brain. Lastly, functionalization of neural probe surfaces with coatings inspired by biology leads to enhanced tissue acceptance over extended timescales. Bioinspired neural interfaces will facilitate future developments in neuroscience studies and neurological treatments by leveraging bidirectional information transfer and integrating neuromorphic computing elements.
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Affiliation(s)
- Grace A. Woods
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, California, 94305, USA
| | - Nicholas J. Rommelfanger
- Department of Applied Physics, Stanford University, Stanford, California, 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, California, 94305, USA
| | - Guosong Hong
- Department of Materials Science and Engineering, Stanford University, Stanford, California, 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, California, 94305, USA
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Liu J, Qu S, Suo Z, Yang W. Functional hydrogel coatings. Natl Sci Rev 2020; 8:nwaa254. [PMID: 34691578 PMCID: PMC8288423 DOI: 10.1093/nsr/nwaa254] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/21/2022] Open
Abstract
Hydrogels—natural or synthetic polymer networks that swell in water—can be made mechanically, chemically and electrically compatible with living tissues. There has been intense research and development of hydrogels for medical applications since the invention of hydrogel contact lenses in 1960. More recently, functional hydrogel coatings with controlled thickness and tough adhesion have been achieved on various substrates. Hydrogel-coated substrates combine the advantages of hydrogels, such as lubricity, biocompatibility and anti-biofouling properties, with the advantages of substrates, such as stiffness, toughness and strength. In this review, we focus on three aspects of functional hydrogel coatings: (i) applications and functions enabled by hydrogel coatings, (ii) methods of coating various substrates with different functional hydrogels with tough adhesion, and (iii) tests to evaluate the adhesion between functional hydrogel coatings and substrates. Conclusions and outlook are given at the end of this review.
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Affiliation(s)
- Junjie Liu
- Center for X-Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province and Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China
- State Key Laboratory of Fluid Power and Mechatronic System, Zhejiang University, Hangzhou 310027, China
- Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China
| | - Shaoxing Qu
- Center for X-Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province and Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China
- State Key Laboratory of Fluid Power and Mechatronic System, Zhejiang University, Hangzhou 310027, China
| | - Zhigang Suo
- John A. Paulson School of Engineering and Applied Sciences, Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, MA 02138, USA
| | - Wei Yang
- Center for X-Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province and Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China
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45
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He F, Lycke R, Ganji M, Xie C, Luan L. Ultraflexible Neural Electrodes for Long-Lasting Intracortical Recording. iScience 2020; 23:101387. [PMID: 32745989 PMCID: PMC7398974 DOI: 10.1016/j.isci.2020.101387] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 06/22/2020] [Accepted: 07/16/2020] [Indexed: 11/16/2022] Open
Abstract
Implanted electrodes provide one of the most important neurotechniques for fundamental and translational neurosciences by permitting time-resolved electrical detection of individual neurons in vivo. However, conventional rigid electrodes typically cannot provide stable, long-lasting recordings. Numerous interwoven biotic and abiotic factors at the tissue-electrode interface lead to short- and long-term instability of the recording performance. Making neural electrodes flexible provides a promising approach to mitigate these challenges on the implants and at the tissue-electrode interface. Here we review the recent progress of ultraflexible neural electrodes and discuss the engineering principles, the material properties, and the implantation strategies to achieve stable tissue-electrode interface and reliable unit recordings in living brains.
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Affiliation(s)
- Fei He
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA; NeuroEngineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA
| | - Roy Lycke
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA; NeuroEngineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA; Department of Biomedical Engineering, University of Texas at Austin, 107 Dean Keeton, Austin, TX 78712, USA
| | - Mehran Ganji
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA; NeuroEngineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA; Department of Biomedical Engineering, University of Texas at Austin, 107 Dean Keeton, Austin, TX 78712, USA
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA; NeuroEngineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA; Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Lan Luan
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA; NeuroEngineering Initiative, Rice University, 6500 Main Street, Houston, TX 77005, USA; Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA.
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46
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McAvoy M, Doloff JC, Khan OF, Rosen J, Langer R, Anderson DG. Vascularized Muscle Flap to Reduce Wound Breakdown During Flexible Electrode-Mediated Functional Electrical Stimulation After Peripheral Nerve Injury. Front Neurol 2020; 11:644. [PMID: 32793094 PMCID: PMC7385241 DOI: 10.3389/fneur.2020.00644] [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: 04/08/2020] [Accepted: 05/29/2020] [Indexed: 11/15/2022] Open
Abstract
The success of devices delivering functional electrical stimulation (FES) has been hindered by complications related to implants including skin breakdown and subsequent wound dehiscence. Our hypothesis was that a vascularized muscle flap along the dorsal surface of an epimysial electrode would prevent skin breakdown during FES therapy to treat atrophy of the gastrocnemius muscle during peripheral nerve injury. Resection of a tibial nerve segment with subsequent electrode implantation on the dorsal surfaces of the gastrocnemius muscle was performed on ten Lewis rats. In five rats, the biceps femoris (BF) muscle was dissected and placed along the dorsal surface of the electrode (Flap group). The other five animals did not undergo flap placement (No Flap group). All animals were treated with daily FES therapy for 2 weeks and degree of immune response and skin breakdown were evaluated. The postoperative course of one animal in the No Flap group was complicated by complete wound dehiscence requiring euthanasia of the animal on postoperative day 4. The remaining 4 No Flap animals showed evidence of ulceration at the implant by postoperative day 7. The 5 animals in the Flap group did not have ulcerative lesions. Excised tissue at postoperative day 14 examined by histology and in vivo Imaging System (IVIS) showed decreased implant-induced inflammation in the Flap group. Expression of specific markers for local foreign body response were also decreased in the Flap group.
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Affiliation(s)
- Malia McAvoy
- Harvard-MIT Division of Health Sciences and Technology, Harvard Medical School, Massachusetts Institute of Technology, Boston, MA, United States
| | - Joshua C Doloff
- Department of Biomedical Engineering, Translational Tissue Engineering Center, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Department of Materials Science and Engineering, Institute of NanoBioTechnology, Johns Hopkins University, Baltimore, MD, United States
| | - Omar F Khan
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Department of Immunology, University of Toronto, Toronto, ON, Canada
| | - Joseph Rosen
- Dartmouth-Hitchcock Medical Center, Geisel School of Medicine, Lebanon, NH, United States
| | - Robert Langer
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Biomedical and Materials Science Engineering, Translational Tissue Engineering Center, Wilmer Eye Institute and the Institute for NanoBioTechnology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Daniel G Anderson
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Biomedical and Materials Science Engineering, Translational Tissue Engineering Center, Wilmer Eye Institute and the Institute for NanoBioTechnology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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47
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Kollo M, Racz R, Hanna ME, Obaid A, Angle MR, Wray W, Kong Y, Müller J, Hierlemann A, Melosh NA, Schaefer AT. CHIME: CMOS-Hosted in vivo Microelectrodes for Massively Scalable Neuronal Recordings. Front Neurosci 2020; 14:834. [PMID: 32848584 PMCID: PMC7432274 DOI: 10.3389/fnins.2020.00834] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 07/16/2020] [Indexed: 01/20/2023] Open
Abstract
Mammalian brains consist of 10s of millions to 100s of billions of neurons operating at millisecond time scales, of which current recording techniques only capture a tiny fraction. Recording techniques capable of sampling neural activity at high spatiotemporal resolution have been difficult to scale. The most intensively studied mammalian neuronal networks, such as the neocortex, show a layered architecture, where the optimal recording technology samples densely over large areas. However, the need for application-specific designs as well as the mismatch between the three-dimensional architecture of the brain and largely two-dimensional microfabrication techniques profoundly limits both neurophysiological research and neural prosthetics. Here, we discuss a novel strategy for scalable neuronal recording by combining bundles of glass-ensheathed microwires with large-scale amplifier arrays derived from high-density CMOS in vitro MEA systems or high-speed infrared cameras. High signal-to-noise ratio (<25 μV RMS noise floor, SNR up to 25) is achieved due to the high conductivity of core metals in glass-ensheathed microwires allowing for ultrathin metal cores (down to <1 μm) and negligible stray capacitance. Multi-step electrochemical modification of the tip enables ultra-low access impedance with minimal geometric area, which is largely independent of the core diameter. We show that the microwire size can be reduced to virtually eliminate damage to the blood-brain-barrier upon insertion and we demonstrate that microwire arrays can stably record single-unit activity. Combining microwire bundles and CMOS arrays allows for a highly scalable neuronal recording approach, linking the progress in electrical neuronal recordings to the rapid progress in silicon microfabrication. The modular design of the system allows for custom arrangement of recording sites. Our approach of employing bundles of minimally invasive, highly insulated and functionalized microwires to extend a two-dimensional CMOS architecture into the 3rd dimension can be translated to other CMOS arrays, such as electrical stimulation devices.
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Affiliation(s)
- Mihaly Kollo
- Neurophysiology of Behaviour Laboratory, Francis Crick Institute, London, United Kingdom
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Romeo Racz
- Neurophysiology of Behaviour Laboratory, Francis Crick Institute, London, United Kingdom
| | - Mina-Elraheb Hanna
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, United States
- Paradromics, Inc., Austin, TX, United States
| | - Abdulmalik Obaid
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, United States
| | | | - William Wray
- Neurophysiology of Behaviour Laboratory, Francis Crick Institute, London, United Kingdom
| | - Yifan Kong
- Paradromics, Inc., Austin, TX, United States
| | - Jan Müller
- ETH Zürich, Department of Biosystems Science and Engineering, Basel, Switzerland
- MaxWell Biosystems AG, Zurich, Switzerland
| | - Andreas Hierlemann
- ETH Zürich, Department of Biosystems Science and Engineering, Basel, Switzerland
| | - Nicholas A. Melosh
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, United States
| | - Andreas T. Schaefer
- Neurophysiology of Behaviour Laboratory, Francis Crick Institute, London, United Kingdom
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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Wang X, Weltman Hirschberg A, Xu H, Slingsby-Smith Z, Lecomte A, Scholten K, Song D, Meng E. A Parylene Neural Probe Array for Multi-Region Deep Brain Recordings. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS : A JOINT IEEE AND ASME PUBLICATION ON MICROSTRUCTURES, MICROACTUATORS, MICROSENSORS, AND MICROSYSTEMS 2020; 29:499-513. [PMID: 35663261 PMCID: PMC9164222 DOI: 10.1109/jmems.2020.3000235] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A Parylene C polymer neural probe array with 64 electrodes purposefully positioned across 8 individual shanks to anatomically match specific regions of the hippocampus was designed, fabricated, characterized, and implemented in vivo for enabling recording in deep brain regions in freely moving rats. Thin film polymer arrays were fabricated using surface micromachining techniques and mechanically braced to prevent buckling during surgical implantation. Importantly, the mechanical bracing technique developed in this work involves a novel biodegradable polymer brace that temporarily reduces shank length and consequently, increases its stiffness during implantation, therefore enabling access to deeper brain regions while preserving a low original cross-sectional area of the shanks. The resulting mechanical properties of braced shanks were evaluated at the benchtop. Arrays were then implemented in vivo in freely moving rats, achieving both acute and chronic recordings from the pyramidal cells in the cornu ammonis (CA) 1 and CA3 regions of the hippocampus which are responsible for memory encoding. This work demonstrated the potential for minimally invasive polymer-based neural probe arrays for multi-region recording in deep brain structures.
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Affiliation(s)
- Xuechun Wang
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | | | - Huijing Xu
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | | | - Aziliz Lecomte
- Fondazione Istituto Italiano di Technologia, 16163 Genova, Italy
| | - Kee Scholten
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | - Dong Song
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | - Ellis Meng
- Biomedical Engineering and Electrical and Computer Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
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49
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Chen N, Luo B, Patil AC, Wang J, Gammad GGL, Yi Z, Liu X, Yen SC, Ramakrishna S, Thakor NV. Nanotunnels within Poly(3,4-ethylenedioxythiophene)-Carbon Nanotube Composite for Highly Sensitive Neural Interfacing. ACS NANO 2020; 14:8059-8073. [PMID: 32579337 DOI: 10.1021/acsnano.0c00672] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Neural electrodes are developed for direct communication with neural tissues for theranostics. Although various strategies have been employed to improve performance, creating an intimate electrode-tissue interface with high electrical fidelity remains a great challenge. Here, we report the rational design of a tunnel-like electrode coating comprising poly(3,4-ethylenedioxythiophene) (PEDOT) and carbon nanotubes (CNTs) for highly sensitive neural recording. The coated electrode shows a 50-fold reduction in electrochemical impedance at the biologically relevant frequency of 1 kHz, compared to the bare gold electrode. The incorporation of CNT significantly reinforces the nanotunnel structure and improves coating adhesion by ∼1.5 fold. In vitro primary neuron culture confirms an intimate contact between neurons and the PEDOT-CNT nanotunnel. During acute in vivo nerve recording, the coated electrode enables the capture of high-fidelity neural signals with low susceptibility to electrical noise and reveals the potential for precisely decoding sensory information through mechanical and thermal stimulation. These findings indicate that the PEDOT-CNT nanotunnel composite serves as an active interfacing material for neural electrodes, contributing to neural prosthesis and brain-machine interface.
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Affiliation(s)
- Nuan Chen
- Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore
- SINAPSE Laboratory, Department of Biomedical Engineering, National University of Singapore, Singapore 117456, Singapore
- The N.1 Institute for Health, National University of Singapore, Singapore 117456, Singapore
| | - Baiwen Luo
- The N.1 Institute for Health, National University of Singapore, Singapore 117456, Singapore
| | - Anoop C Patil
- SINAPSE Laboratory, Department of Biomedical Engineering, National University of Singapore, Singapore 117456, Singapore
- The N.1 Institute for Health, National University of Singapore, Singapore 117456, Singapore
| | - Jiahui Wang
- The N.1 Institute for Health, National University of Singapore, Singapore 117456, Singapore
| | | | - Zhigao Yi
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Xiaogang Liu
- The N.1 Institute for Health, National University of Singapore, Singapore 117456, Singapore
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Shih-Cheng Yen
- The N.1 Institute for Health, National University of Singapore, Singapore 117456, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
| | - Seeram Ramakrishna
- Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore
| | - Nitish V Thakor
- SINAPSE Laboratory, Department of Biomedical Engineering, National University of Singapore, Singapore 117456, Singapore
- The N.1 Institute for Health, National University of Singapore, Singapore 117456, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
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50
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Keogh C. Optimizing the neuron-electrode interface for chronic bioelectronic interfacing. Neurosurg Focus 2020; 49:E7. [PMID: 32610294 DOI: 10.3171/2020.4.focus20178] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 04/08/2020] [Indexed: 11/06/2022]
Abstract
Engineering approaches have vast potential to improve the treatment of disease. Brain-machine interfaces have become a well-established means of treating some otherwise medically refractory neurological diseases, and they have shown promise in many more areas. More widespread use of implanted stimulating and recording electrodes for long-term intervention is, however, limited by the difficulty in maintaining a stable interface between implanted electrodes and the local tissue for reliable recording and stimulation.This loss of performance at the neuron-electrode interface is due to a combination of inflammation and glial scar formation in response to the implanted material, as well as electrical factors contributing to a reduction in function over time. An increasing understanding of the factors at play at the neural interface has led to greater focus on the optimization of this neuron-electrode interface in order to maintain long-term implant viability.A wide variety of approaches to improving device interfacing have emerged, targeting the mechanical, electrical, and biological interactions between implanted electrodes and the neural tissue. These approaches are aimed at reducing the initial trauma and long-term tissue reaction through device coatings, optimization of mechanical characteristics for maximal biocompatibility, and implantation techniques. Improved electrode features, optimized stimulation parameters, and novel electrode materials further aim to stabilize the electrical interface, while the integration of biological interventions to reduce inflammation and improve tissue integration has also shown promise.Optimization of the neuron-electrode interface allows the use of long-term, high-resolution stimulation and recording, opening the door to responsive closed-loop systems with highly selective modulation. These new approaches and technologies offer a broad range of options for neural interfacing, representing the possibility of developing specific implant technologies tailor-made to a given task, allowing truly personalized, optimized implant technology for chronic neural interfacing.
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