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Greenhorn S, Bano E, Stambouli V, Zekentes K. Amorphous SiC Thin Films Deposited by Plasma-Enhanced Chemical Vapor Deposition for Passivation in Biomedical Devices. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1135. [PMID: 38473606 DOI: 10.3390/ma17051135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/22/2024] [Accepted: 02/26/2024] [Indexed: 03/14/2024]
Abstract
Amorphous silicon carbide (a-SiC) is a wide-bandgap semiconductor with high robustness and biocompatibility, making it a promising material for applications in biomedical device passivation. a-SiC thin film deposition has been a subject of research for several decades with a variety of approaches investigated to achieve optimal properties for multiple applications, with an emphasis on properties relevant to biomedical devices in the past decade. This review summarizes the results of many optimization studies, identifying strategies that have been used to achieve desirable film properties and discussing the proposed physical interpretations. In addition, divergent results from studies are contrasted, with attempts to reconcile the results, while areas of uncertainty are highlighted.
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Affiliation(s)
- Scott Greenhorn
- The Institute of Electronic Structure and Laser of the Foundation for Research and Technology-Hellas (MRG-IESL/FORTH), GR-70013 Heraklion, Greece
- Laboratoire des Matériaux et de la Génie Physique, Université Grenoble Alpes, Centre National de la Recherche Scientifique, Institut Polytechnique de Grenoble, 38016 Grenoble, France
- Centre de Radiofréquences, Optique et Micro-nanoélectronique des Alpes, Université Grenoble Alpes, Centre National de la Recherche Scientifique, Institut Polytechnique de Grenoble, 38016 Grenoble, France
| | - Edwige Bano
- Centre de Radiofréquences, Optique et Micro-nanoélectronique des Alpes, Université Grenoble Alpes, Centre National de la Recherche Scientifique, Institut Polytechnique de Grenoble, 38016 Grenoble, France
| | - Valérie Stambouli
- Laboratoire des Matériaux et de la Génie Physique, Université Grenoble Alpes, Centre National de la Recherche Scientifique, Institut Polytechnique de Grenoble, 38016 Grenoble, France
| | - Konstantinos Zekentes
- The Institute of Electronic Structure and Laser of the Foundation for Research and Technology-Hellas (MRG-IESL/FORTH), GR-70013 Heraklion, Greece
- Centre de Radiofréquences, Optique et Micro-nanoélectronique des Alpes, Université Grenoble Alpes, Centre National de la Recherche Scientifique, Institut Polytechnique de Grenoble, 38016 Grenoble, France
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2
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La Via F, Alquier D, Giannazzo F, Kimoto T, Neudeck P, Ou H, Roncaglia A, Saddow SE, Tudisco S. Emerging SiC Applications beyond Power Electronic Devices. MICROMACHINES 2023; 14:1200. [PMID: 37374785 PMCID: PMC10300968 DOI: 10.3390/mi14061200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 06/29/2023]
Abstract
In recent years, several new applications of SiC (both 4H and 3C polytypes) have been proposed in different papers. In this review, several of these emerging applications have been reported to show the development status, the main problems to be solved and the outlooks for these new devices. The use of SiC for high temperature applications in space, high temperature CMOS, high radiation hard detectors, new optical devices, high frequency MEMS, new devices with integrated 2D materials and biosensors have been extensively reviewed in this paper. The development of these new applications, at least for the 4H-SiC ones, has been favored by the strong improvement in SiC technology and in the material quality and price, due to the increasing market for power devices. However, at the same time, these new applications need the development of new processes and the improvement of material properties (high temperature packages, channel mobility and threshold voltage instability improvement, thick epitaxial layers, low defects, long carrier lifetime, low epitaxial doping). Instead, in the case of 3C-SiC applications, several new projects have developed material processes to obtain more performing MEMS, photonics and biomedical devices. Despite the good performance of these devices and the potential market, the further development of the material and of the specific processes and the lack of several SiC foundries for these applications are limiting further development in these fields.
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Affiliation(s)
| | - Daniel Alquier
- GREMAN, UMR 7347, Université de Tours, CNRS, 37071 Tours, France;
| | | | - Tsunenobu Kimoto
- Department of Electronic Science and Engineering, Kyoto University, Nishikyo, Kyoto 615-8510, Japan;
| | - Philip Neudeck
- NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, OH 44135, USA;
| | - Haiyan Ou
- Department of Electrical and Photonics Engineering, Technical University of Denmark, Ørsteds Plads, Building 343, DK-2800 Kgs. Lyngby, Denmark;
| | | | - Stephen E. Saddow
- Electrical Engineering Department, University of South Florida, 4202 E. Fowler Avenue, ENG 030, Tampa, FL 33620, USA;
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Shen K, Chen O, Edmunds JL, Piech DK, Maharbiz MM. Translational opportunities and challenges of invasive electrodes for neural interfaces. Nat Biomed Eng 2023; 7:424-442. [PMID: 37081142 DOI: 10.1038/s41551-023-01021-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 02/15/2023] [Indexed: 04/22/2023]
Abstract
Invasive brain-machine interfaces can restore motor, sensory and cognitive functions. However, their clinical adoption has been hindered by the surgical risk of implantation and by suboptimal long-term reliability. In this Review, we highlight the opportunities and challenges of invasive technology for clinically relevant electrophysiology. Specifically, we discuss the characteristics of neural probes that are most likely to facilitate the clinical translation of invasive neural interfaces, describe the neural signals that can be acquired or produced by intracranial electrodes, the abiotic and biotic factors that contribute to their failure, and emerging neural-interface architectures.
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Affiliation(s)
- Konlin Shen
- University of California, Berkeley - University of California, San Francisco Graduate Program in Bioengineering, Berkeley, CA, USA.
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA.
| | - Oliver Chen
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, USA
| | - Jordan L Edmunds
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, USA
| | - David K Piech
- University of California, Berkeley - University of California, San Francisco Graduate Program in Bioengineering, Berkeley, CA, USA
| | - Michel M Maharbiz
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, USA
- Department of Bioengineering, University of California, Berkeley, CA, USA
- Chan-Zuckerberg Biohub, San Francisco, CA, USA
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Jeakle EN, Abbott JR, Usoro JO, Wu Y, Haghighi P, Radhakrishna R, Sturgill BS, Nakajima S, Thai TTD, Pancrazio JJ, Cogan SF, Hernandez-Reynoso AG. Chronic Stability of Local Field Potentials Using Amorphous Silicon Carbide Microelectrode Arrays Implanted in the Rat Motor Cortex. MICROMACHINES 2023; 14:680. [PMID: 36985087 PMCID: PMC10054633 DOI: 10.3390/mi14030680] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 06/18/2023]
Abstract
Implantable microelectrode arrays (MEAs) enable the recording of electrical activity of cortical neurons, allowing the development of brain-machine interfaces. However, MEAs show reduced recording capabilities under chronic conditions, prompting the development of novel MEAs that can improve long-term performance. Conventional planar, silicon-based devices and ultra-thin amorphous silicon carbide (a-SiC) MEAs were implanted in the motor cortex of female Sprague-Dawley rats, and weekly anesthetized recordings were made for 16 weeks after implantation. The spectral density and bandpower between 1 and 500 Hz of recordings were compared over the implantation period for both device types. Initially, the bandpower of the a-SiC devices and standard MEAs was comparable. However, the standard MEAs showed a consistent decline in both bandpower and power spectral density throughout the 16 weeks post-implantation, whereas the a-SiC MEAs showed substantially more stable performance. These differences in bandpower and spectral density between standard and a-SiC MEAs were statistically significant from week 6 post-implantation until the end of the study at 16 weeks. These results support the use of ultra-thin a-SiC MEAs to develop chronic, reliable brain-machine interfaces.
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Affiliation(s)
- Eleanor N. Jeakle
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Justin R. Abbott
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Joshua O. Usoro
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Yupeng Wu
- Department of Materials Science and Engineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Pegah Haghighi
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Rahul Radhakrishna
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Brandon S. Sturgill
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Shido Nakajima
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Teresa T. D. Thai
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Joseph J. Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Stuart F. Cogan
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
| | - Ana G. Hernandez-Reynoso
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA
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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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Balakrishnan G, Song J, Mou C, Bettinger CJ. Recent Progress in Materials Chemistry to Advance Flexible Bioelectronics in Medicine. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106787. [PMID: 34751987 PMCID: PMC8917047 DOI: 10.1002/adma.202106787] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/15/2021] [Indexed: 05/09/2023]
Abstract
Designing bioelectronic devices that seamlessly integrate with the human body is a technological pursuit of great importance. Bioelectronic medical devices that reliably and chronically interface with the body can advance neuroscience, health monitoring, diagnostics, and therapeutics. Recent major efforts focus on investigating strategies to fabricate flexible, stretchable, and soft electronic devices, and advances in materials chemistry have emerged as fundamental to the creation of the next generation of bioelectronics. This review summarizes contemporary advances and forthcoming technical challenges related to three principal components of bioelectronic devices: i) substrates and structural materials, ii) barrier and encapsulation materials, and iii) conductive materials. Through notable illustrations from the literature, integration and device fabrication strategies and associated challenges for each material class are highlighted.
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Affiliation(s)
| | - Jiwoo Song
- Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA
| | - Chenchen Mou
- Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA
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Wu X, Fan T, Eftekhar AA, Hosseinnia AH, Adibi A. High-Q ultrasensitive integrated photonic sensors based on slot-ring resonator on a 3C-SiC-on-insulator platform. OPTICS LETTERS 2021; 46:4316-4319. [PMID: 34470003 DOI: 10.1364/ol.434689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate, to the best of our knowledge, the first high-Q silicon carbide (SiC) integrated photonic sensor based on slot-ring resonators on a 3C-SiC-on-insulator (SiCOI) platform. We experimentally demonstrate an intrinsic Q of 17,400 at around 1310 nm wavelength for a slot-ring resonator with 40 µm radius with water cladding. By applying different concentrations of a sodium chloride (NaCl) solution that covers the devices, measured bulk sensitivities of 264-300 nm/RIU (refractive index unit) are achieved in the slot-ring resonator with a 400-450 nm rail width and a 100-200 nm slot width. The device performance for biomolecular layer sensing (BMLS) is proved by the detection of the cardiac biomarker troponin with 248-322 pm/nm surface sensitivity. The reported slot-ring resonators can be of great interest for diverse sensing applications from visible to infrared wavelengths.
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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: 15] [Impact Index Per Article: 5.0] [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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Silvestri A, Di Trani N, Canavese G, Motto Ros P, Iannucci L, Grassini S, Wang Y, Liu X, Demarchi D, Grattoni A. Silicon Carbide-Gated Nanofluidic Membrane for Active Control of Electrokinetic Ionic Transport. MEMBRANES 2021; 11:535. [PMID: 34357186 PMCID: PMC8303522 DOI: 10.3390/membranes11070535] [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: 06/19/2021] [Revised: 07/06/2021] [Accepted: 07/12/2021] [Indexed: 11/16/2022]
Abstract
Manipulation of ions and molecules by external control at the nanoscale is highly relevant to biomedical applications. We report a biocompatible electrode-embedded nanofluidic channel membrane designed for electrofluidic applications such as ionic field-effect transistors for implantable drug-delivery systems. Our nanofluidic membrane includes a polysilicon electrode electrically isolated by amorphous silicon carbide (a-SiC). The nanochannel gating performance was experimentally investigated based on the current-voltage (I-V) characteristics, leakage current, and power consumption in potassium chloride (KCl) electrolyte. We observed significant modulation of ionic diffusive transport of both positively and negatively charged ions under physical confinement of nanochannels, with low power consumption. To study the physical mechanism associated with the gating performance, we performed electrochemical impedance spectroscopy. The results showed that the flat band voltage and density of states were significantly low. In light of its remarkable performance in terms of ionic modulation and low power consumption, this new biocompatible nanofluidic membrane could lead to a new class of silicon implantable nanofluidic systems for tunable drug delivery and personalized medicine.
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Affiliation(s)
- Antonia Silvestri
- Department of Electronics and Telecommunications, Polytechnic of Turin, 10129 Turin, Italy; (A.S.); (P.M.R.); (D.D.)
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA; (N.D.T.); (Y.W.); (X.L.)
| | - Nicola Di Trani
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA; (N.D.T.); (Y.W.); (X.L.)
| | - Giancarlo Canavese
- Department of Applied Science and Technology, Polytechnic of Turin, 10129 Turin, Italy; (G.C.); (L.I.); (S.G.)
| | - Paolo Motto Ros
- Department of Electronics and Telecommunications, Polytechnic of Turin, 10129 Turin, Italy; (A.S.); (P.M.R.); (D.D.)
| | - Leonardo Iannucci
- Department of Applied Science and Technology, Polytechnic of Turin, 10129 Turin, Italy; (G.C.); (L.I.); (S.G.)
| | - Sabrina Grassini
- Department of Applied Science and Technology, Polytechnic of Turin, 10129 Turin, Italy; (G.C.); (L.I.); (S.G.)
| | - Yu Wang
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA; (N.D.T.); (Y.W.); (X.L.)
| | - Xuewu Liu
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA; (N.D.T.); (Y.W.); (X.L.)
| | - Danilo Demarchi
- Department of Electronics and Telecommunications, Polytechnic of Turin, 10129 Turin, Italy; (A.S.); (P.M.R.); (D.D.)
| | - Alessandro Grattoni
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030, USA; (N.D.T.); (Y.W.); (X.L.)
- Department of Surgery, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX 77030, USA
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Abstract
The lifetime of neural implants is strongly dependent on packaging due to the aqueous and biochemically aggressive nature of the body. Over the last decade, there has been a drive towards neuromodulatory implants which are wireless and approaching millimeter-scales with increasing electrode count. A so-far unrealized goal for these new types of devices is an in-vivo lifetime comparable to a sizable fraction of a healthy patient's lifetime (>10-20 years). Existing, approved medical implants commonly encapsulate components in metal enclosures (e.g. titanium) with brazed ceramic inserts for electrode feedthrough. It is unclear how amenable the traditional approach is to the simultaneous goals of miniaturization, increased channel count, and wireless communication. Ceramic materials have also played a significant role in traditional medical implants due to their dielectric properties, corrosion resistance, biocompatibility, and high strength, but are not as commonly used for housing materials due to their brittleness and the difficulty they present in creating complex housing geometries. However, thin-film technology has opened new opportunities for ceramics processing. Thin films derived largely from the semiconductor industry can be deposited and patterned in new ways, have conductivities which can be altered during manufacturing to provide conductors as well as insulators, and can be used to fabricate flexible substrates. In this review, we give an overview of packaging for neural implants, with an emphasis on how ceramic materials have been utilized in medical device packaging, as well as how ceramic thin-film micromachining and processing may be further developed to create truly reliable, miniaturized, neural implants.
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Affiliation(s)
- Konlin Shen
- University of California, Berkeley-University of California, San Francisco Graduate Program in Bioengineering, Berkeley, CA, United States of America
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Silicon Carbide and MRI: Towards Developing a MRI Safe Neural Interface. MICROMACHINES 2021; 12:mi12020126. [PMID: 33530350 PMCID: PMC7911642 DOI: 10.3390/mi12020126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 12/11/2022]
Abstract
An essential method to investigate neuromodulation effects of an invasive neural interface (INI) is magnetic resonance imaging (MRI). Presently, MRI imaging of patients with neural implants is highly restricted in high field MRI (e.g., 3 T and higher) due to patient safety concerns. This results in lower resolution MRI images and, consequently, degrades the efficacy of MRI imaging for diagnostic purposes in these patients. Cubic silicon carbide (3C-SiC) is a biocompatible wide-band-gap semiconductor with a high thermal conductivity and magnetic susceptibility compatible with brain tissue. It also has modifiable electrical conductivity through doping level control. These properties can improve the MRI compliance of 3C-SiC INIs, specifically in high field MRI scanning. In this work, the MRI compliance of epitaxial SiC films grown on various Si wafers, used to implement a monolithic neural implant (all-SiC), was studied. Via finite element method (FEM) and Fourier-based simulations, the specific absorption rate (SAR), induced heating, and image artifacts caused by the portion of the implant within a brain tissue phantom located in a 7 T small animal MRI machine were estimated and measured. The specific goal was to compare implant materials; thus, the effect of leads outside the tissue was not considered. The results of the simulations were validated via phantom experiments in the same 7 T MRI system. The simulation and experimental results revealed that free-standing 3C-SiC films had little to no image artifacts compared to silicon and platinum reference materials inside the MRI at 7 T. In addition, FEM simulations predicted an ~30% SAR reduction for 3C-SiC compared to Pt. These initial simulations and experiments indicate an all-SiC INI may effectively reduce MRI induced heating and image artifacts in high field MRI. In order to evaluate the MRI safety of a closed-loop, fully functional all-SiC INI as per ISO/TS 10974:2018 standard, additional research and development is being conducted and will be reported at a later date.
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Shire DB, Gingerich MD, Wong PI, Skvarla M, Cogan SF, Chen J, Wang W, Rizzo JF. Micro-Fabrication of Components for a High-Density Sub-Retinal Visual Prosthesis. MICROMACHINES 2020; 11:mi11100944. [PMID: 33086504 PMCID: PMC7603138 DOI: 10.3390/mi11100944] [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: 08/29/2020] [Revised: 10/10/2020] [Accepted: 10/13/2020] [Indexed: 01/30/2023]
Abstract
We present a retrospective of unique micro-fabrication problems and solutions that were encountered through over 10 years of retinal prosthesis product development, first for the Boston Retinal Implant Project initiated at the Massachusetts Institute of Technology and at Harvard Medical School’s teaching hospital, the Massachusetts Eye and Ear—and later at the startup company Bionic Eye Technologies, by some of the same personnel. These efforts culminated in the fabrication and assembly of 256+ channel visual prosthesis devices having flexible multi-electrode arrays that were successfully implanted sub-retinally in mini-pig animal models as part of our pre-clinical testing program. We report on the processing of the flexible multi-layered, planar and penetrating high-density electrode arrays, surgical tools for sub-retinal implantation, and other parts such as coil supports that facilitated the implantation of the peri-ocular device components. We begin with an overview of the implantable portion of our visual prosthesis system design, and describe in detail the micro-fabrication methods for creating the parts of our system that were assembled outside of our hermetically-sealed electronics package. We also note the unique surgical challenges that sub-retinal implantation of our micro-fabricated components presented, and how some of those issues were addressed through design, materials selection, and fabrication approaches.
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Affiliation(s)
- Douglas B. Shire
- Bionic Eye Technologies, Inc., Ithaca, NY 14850, USA; (M.D.G.); (P.I.W.)
- Correspondence: ; Tel.: +1-607-339-7085
| | | | - Patricia I. Wong
- Bionic Eye Technologies, Inc., Ithaca, NY 14850, USA; (M.D.G.); (P.I.W.)
| | - Michael Skvarla
- Cornell NanoScale Science and Technology Facility, Ithaca, NY 14853, USA;
| | - Stuart F. Cogan
- Department of Bioengineering, University of Texas, Dallas, Richardson, TX 75080, USA;
| | - Jinghua Chen
- Department of Ophthalmology, University of Florida, Gainesville, FL 32611, USA;
| | - Wei Wang
- Department of Ophthalmology, University of Louisville, Louisville, KY 40292, USA;
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Song E, Li J, Won SM, Bai W, Rogers JA. Materials for flexible bioelectronic systems as chronic neural interfaces. NATURE MATERIALS 2020; 19:590-603. [PMID: 32461684 DOI: 10.1038/s41563-020-0679-7] [Citation(s) in RCA: 173] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/09/2020] [Indexed: 05/03/2023]
Abstract
Engineered systems that can serve as chronically stable, high-performance electronic recording and stimulation interfaces to the brain and other parts of the nervous system, with cellular-level resolution across macroscopic areas, are of broad interest to the neuroscience and biomedical communities. Challenges remain in the development of biocompatible materials and the design of flexible implants for these purposes, where ulimate goals are for performance attributes approaching those of conventional wafer-based technologies and for operational timescales reaching the human lifespan. This Review summarizes recent advances in this field, with emphasis on active and passive constituent materials, design architectures and integration methods that support necessary levels of biocompatibility, electronic functionality, long-term stable operation in biofluids and reliability for use in vivo. Bioelectronic systems that enable multiplexed electrophysiological mapping across large areas at high spatiotemporal resolution are surveyed, with a particular focus on those with proven chronic stability in live animal models and scalability to thousands of channels over human-brain-scale dimensions. Research in materials science will continue to underpin progress in this field of study.
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Affiliation(s)
- Enming Song
- Center for Bio-Integrated Electronics, Northwestern University, Evanston, IL, USA
| | - Jinghua Li
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, USA
- Center for Chronic Brain Injury, The Ohio State University, Columbus, OH, USA
| | - Sang Min Won
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Wubin Bai
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA
| | - John A Rogers
- Center for Bio-Integrated Electronics, Northwestern University, Evanston, IL, USA.
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA.
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
- Department of Neurological Surgery, Northwestern University, Evanston, IL, USA.
- Department of Chemistry, Northwestern University, Evanston, IL, USA.
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA.
- Department of Electrical Engineering, Northwestern University, Evanston, IL, USA.
- Department of Computer Science, Northwestern University, Evanston, IL, USA.
- Feinberg School of Medicine, Northwestern University, Evanston, IL, USA.
- Querrey-Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA.
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McHail DG, Dumas TC. Hippocampal gamma rhythms during Y‐maze navigation in the juvenile rat. Hippocampus 2020; 30:505-525. [DOI: 10.1002/hipo.23168] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 09/01/2019] [Accepted: 09/17/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Daniel G. McHail
- Interdisciplinary Program in NeuroscienceGeorge Mason University Fairfax Virginia
| | - Theodore C. Dumas
- Interdisciplinary Program in NeuroscienceGeorge Mason University Fairfax Virginia
- Psychology DepartmentGeorge Mason University Fairfax Virginia
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15
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Sung C, Jeon W, Nam KS, Kim Y, Butt H, Park S. Multimaterial and multifunctional neural interfaces: from surface-type and implantable electrodes to fiber-based devices. J Mater Chem B 2020; 8:6624-6666. [DOI: 10.1039/d0tb00872a] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Development of neural interfaces from surface electrodes to fibers with various type, functionality, and materials.
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Affiliation(s)
- Changhoon Sung
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Woojin Jeon
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Kum Seok Nam
- School of Electrical Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Yeji Kim
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
| | - Haider Butt
- Department of Mechanical Engineering
- Khalifa University
- Abu Dhabi 127788
- United Arab Emirates
| | - Seongjun Park
- Department of Bio and Brain Engineering
- Korea Advanced Institute of Science and Technology (KAIST)
- Daejeon 34141
- Republic of Korea
- KAIST Institute for Health Science and Technology (KIHST)
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16
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Shoffstall AJ, Capadona JR. Bioelectronic Neural Implants. Biomater Sci 2020. [DOI: 10.1016/b978-0-12-816137-1.00073-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Usoro JO, Shih E, Black BJ, Rihani RT, Abbott J, Chakraborty B, Pancrazio JJ, Cogan SF. Chronic stability of local field potentials from standard and modified Blackrock microelectrode arrays implanted in the rat motor cortex. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/ab4c02] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Deku F, Cohen Y, Joshi-Imre A, Kanneganti A, Gardner TJ, Cogan SF. Amorphous silicon carbide ultramicroelectrode arrays for neural stimulation and recording. J Neural Eng 2019; 15:016007. [PMID: 28952963 DOI: 10.1088/1741-2552/aa8f8b] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Foreign body response to indwelling cortical microelectrodes limits the reliability of neural stimulation and recording, particularly for extended chronic applications in behaving animals. The extent to which this response compromises the chronic stability of neural devices depends on many factors including the materials used in the electrode construction, the size, and geometry of the indwelling structure. Here, we report on the development of microelectrode arrays (MEAs) based on amorphous silicon carbide (a-SiC). APPROACH This technology utilizes a-SiC for its chronic stability and employs semiconductor manufacturing processes to create MEAs with small shank dimensions. The a-SiC films were deposited by plasma enhanced chemical vapor deposition and patterned by thin-film photolithographic techniques. To improve stimulation and recording capabilities with small contact areas, we investigated low impedance coatings on the electrode sites. The assembled devices were characterized in phosphate buffered saline for their electrochemical properties. MAIN RESULTS MEAs utilizing a-SiC as both the primary structural element and encapsulation were fabricated successfully. These a-SiC MEAs had 16 penetrating shanks. Each shank has a cross-sectional area less than 60 µm2 and electrode sites with a geometric surface area varying from 20 to 200 µm2. Electrode coatings of TiN and SIROF reduced 1 kHz electrode impedance to less than 100 kΩ from ~2.8 MΩ for 100 µm2 Au electrode sites and increased the charge injection capacities to values greater than 3 mC cm-2. Finally, we demonstrated functionality by recording neural activity from basal ganglia nucleus of Zebra Finches and motor cortex of rat. SIGNIFICANCE The a-SiC MEAs provide a significant advancement in the development of microelectrodes that over the years has relied on silicon platforms for device manufacture. These flexible a-SiC MEAs have the potential for decreased tissue damage and reduced foreign body response. The technique is promising and has potential for clinical translation and large scale manufacturing.
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Affiliation(s)
- Felix Deku
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, United States of America
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19
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Park JH, Song Z, Lee GY, Jeong SM, Kang MJ, Pyun JC. Hypersensitive electrochemical immunoassays based on highly N-doped silicon carbide (SiC) electrode. Anal Chim Acta 2019; 1073:30-38. [DOI: 10.1016/j.aca.2019.04.054] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 12/20/2022]
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20
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Joshi-Imre A, Black BJ, Abbott J, Kanneganti A, Rihani R, Chakraborty B, Danda VR, Maeng J, Sharma R, Rieth L, Negi S, Pancrazio JJ, Cogan SF. Chronic recording and electrochemical performance of amorphous silicon carbide-coated Utah electrode arrays implanted in rat motor cortex. J Neural Eng 2019; 16:046006. [DOI: 10.1088/1741-2552/ab1bc8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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21
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Beygi M, Bentley JT, Frewin CL, Kuliasha CA, Takshi A, Bernardin EK, La Via F, Saddow SE. Fabrication of a Monolithic Implantable Neural Interface from Cubic Silicon Carbide. MICROMACHINES 2019; 10:E430. [PMID: 31261887 PMCID: PMC6680876 DOI: 10.3390/mi10070430] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/18/2019] [Accepted: 06/26/2019] [Indexed: 02/07/2023]
Abstract
One of the main issues with micron-sized intracortical neural interfaces (INIs) is their long-term reliability, with one major factor stemming from the material failure caused by the heterogeneous integration of multiple materials used to realize the implant. Single crystalline cubic silicon carbide (3C-SiC) is a semiconductor material that has been long recognized for its mechanical robustness and chemical inertness. It has the benefit of demonstrated biocompatibility, which makes it a promising candidate for chronically-stable, implantable INIs. Here, we report on the fabrication and initial electrochemical characterization of a nearly monolithic, Michigan-style 3C-SiC microelectrode array (MEA) probe. The probe consists of a single 5 mm-long shank with 16 electrode sites. An ~8 µm-thick p-type 3C-SiC epilayer was grown on a silicon-on-insulator (SOI) wafer, which was followed by a ~2 µm-thick epilayer of heavily n-type (n+) 3C-SiC in order to form conductive traces and the electrode sites. Diodes formed between the p and n+ layers provided substrate isolation between the channels. A thin layer of amorphous silicon carbide (a-SiC) was deposited via plasma-enhanced chemical vapor deposition (PECVD) to insulate the surface of the probe from the external environment. Forming the probes on a SOI wafer supported the ease of probe removal from the handle wafer by simple immersion in HF, thus aiding in the manufacturability of the probes. Free-standing probes and planar single-ended test microelectrodes were fabricated from the same 3C-SiC epiwafers. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed on test microelectrodes with an area of 491 µm2 in phosphate buffered saline (PBS) solution. The measurements showed an impedance magnitude of 165 kΩ ± 14.7 kΩ (mean ± standard deviation) at 1 kHz, anodic charge storage capacity (CSC) of 15.4 ± 1.46 mC/cm2, and a cathodic CSC of 15.2 ± 1.03 mC/cm2. Current-voltage tests were conducted to characterize the p-n diode, n-p-n junction isolation, and leakage currents. The turn-on voltage was determined to be on the order of ~1.4 V and the leakage current was less than 8 μArms. This all-SiC neural probe realizes nearly monolithic integration of device components to provide a likely neurocompatible INI that should mitigate long-term reliability issues associated with chronic implantation.
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Affiliation(s)
- Mohammad Beygi
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA
| | - John T Bentley
- Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA
| | | | - Cary A Kuliasha
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Arash Takshi
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA
| | - Evans K Bernardin
- Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA
| | - Francesco La Via
- CNR Institute for Microelectronics and Microsystems, Catania, Sicily 95121, Italy
| | - Stephen E Saddow
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA.
- Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA.
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22
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Mayer M, Baeumner AJ. A Megatrend Challenging Analytical Chemistry: Biosensor and Chemosensor Concepts Ready for the Internet of Things. Chem Rev 2019; 119:7996-8027. [DOI: 10.1021/acs.chemrev.8b00719] [Citation(s) in RCA: 146] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Michael Mayer
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany
| | - Antje J. Baeumner
- Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93040 Regensburg, Germany
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23
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Deku F, Mohammed S, Joshi-Imre A, Maeng J, Danda V, Gardner TJ, Cogan SF. Effect of oxidation on intrinsic residual stress in amorphous silicon carbide films. J Biomed Mater Res B Appl Biomater 2018; 107:1654-1661. [PMID: 30321479 DOI: 10.1002/jbm.b.34258] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/26/2018] [Accepted: 09/16/2018] [Indexed: 11/11/2022]
Abstract
The change in residual stress in plasma enhanced chemical vapor deposition amorphous silicon carbide (a-SiC:H) films exposed to air and wet ambient environments is investigated. A close relationship between stress change and deposition condition is identified from mechanical and chemical characterization of a-SiC:H films. Evidence of amorphous silicon carbide films reacting with oxygen and water vapor in the ambient environment are presented. The effect of deposition parameters on oxidation and stress variation in a-SiC:H film is studied. It is found that the films deposited at low temperature or power are susceptible to oxidation and undergo a notable increase in compressive stress over time. Furthermore, the films deposited at sufficiently high temperature (≥325 C) and power density (≥0.2 W cm-2 ) do not exhibit pronounced oxidation or temporal stress variation. These results serve as the basis for developing amorphous silicon carbide based dielectric encapsulation for implantable medical devices. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1654-1661, 2019.
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Affiliation(s)
- Felix Deku
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas
| | - Shakil Mohammed
- Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas
| | | | - Jimin Maeng
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas
| | - Vindhya Danda
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas
| | - Timothy J Gardner
- Department of Biology and Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Stuart F Cogan
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas
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24
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Deku F, Frewin CL, Stiller A, Cohen Y, Aqeel S, Joshi-Imre A, Black B, Gardner TJ, Pancrazio JJ, Cogan SF. Amorphous Silicon Carbide Platform for Next Generation Penetrating Neural Interface Designs. MICROMACHINES 2018; 9:E480. [PMID: 30424413 PMCID: PMC6215182 DOI: 10.3390/mi9100480] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/09/2018] [Accepted: 09/17/2018] [Indexed: 11/16/2022]
Abstract
Microelectrode arrays that consistently and reliably record and stimulate neural activity under conditions of chronic implantation have so far eluded the neural interface community due to failures attributed to both biotic and abiotic mechanisms. Arrays with transverse dimensions of 10 µm or below are thought to minimize the inflammatory response; however, the reduction of implant thickness also decreases buckling thresholds for materials with low Young's modulus. While these issues have been overcome using stiffer, thicker materials as transport shuttles during implantation, the acute damage from the use of shuttles may generate many other biotic complications. Amorphous silicon carbide (a-SiC) provides excellent electrical insulation and a large Young's modulus, allowing the fabrication of ultrasmall arrays with increased resistance to buckling. Prototype a-SiC intracortical implants were fabricated containing 8 - 16 single shanks which had critical thicknesses of either 4 µm or 6 µm. The 6 µm thick a-SiC shanks could penetrate rat cortex without an insertion aid. Single unit recordings from SIROF-coated arrays implanted without any structural support are presented. This work demonstrates that a-SiC can provide an excellent mechanical platform for devices that penetrate cortical tissue while maintaining a critical thickness less than 10 µm.
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Affiliation(s)
- Felix Deku
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Christopher L Frewin
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Allison Stiller
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Yarden Cohen
- Department of Biology and Biomedical Engineering, Boston University, Boston, MA 02215, USA.
| | - Saher Aqeel
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Alexandra Joshi-Imre
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Bryan Black
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Timothy J Gardner
- Department of Biology and Biomedical Engineering, Boston University, Boston, MA 02215, USA.
| | - Joseph J Pancrazio
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Stuart F Cogan
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
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25
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Stiller AM, Black BJ, Kung C, Ashok A, Cogan SF, Varner VD, Pancrazio JJ. A Meta-Analysis of Intracortical Device Stiffness and Its Correlation with Histological Outcomes. MICROMACHINES 2018; 9:E443. [PMID: 30424376 PMCID: PMC6187651 DOI: 10.3390/mi9090443] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 08/23/2018] [Accepted: 08/30/2018] [Indexed: 01/22/2023]
Abstract
Neural implants offer solutions for a variety of clinical issues. While commercially available devices can record neural signals for short time periods, they fail to do so chronically, partially due to the sustained tissue response around the device. Our objective was to assess the correlation between device stiffness, a function of both material modulus and cross-sectional area, and the severity of immune response. Meta-analysis data were derived from nine previously published studies which reported device material and geometric properties, as well as histological outcomes. Device bending stiffness was calculated by treating the device shank as a cantilevered beam. Immune response was quantified through analysis of immunohistological images from each study, specifically looking at fluorescent markers for neuronal nuclei and astrocytes, to assess neuronal dieback and gliosis. Results demonstrate that the severity of the immune response, within the first 50 µm of the device, is highly correlated with device stiffness, as opposed to device modulus or cross-sectional area independently. In general, commercially available devices are around two to three orders of magnitude higher in stiffness than devices which induced a minimal tissue response. These results have implications for future device designs aiming to decrease chronic tissue response and achieve increased long-term functionality.
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Affiliation(s)
- Allison M Stiller
- Department of Bioengineering, The University of Texas at Dallas, 800W. Campbell Rd., Richardson, TX 75080, USA.
| | - Bryan J Black
- Department of Bioengineering, The University of Texas at Dallas, 800W. Campbell Rd., Richardson, TX 75080, USA.
| | - Christopher Kung
- Department of Bioengineering, The University of Texas at Dallas, 800W. Campbell Rd., Richardson, TX 75080, USA.
| | - Aashika Ashok
- Department of Bioengineering, The University of Texas at Dallas, 800W. Campbell Rd., Richardson, TX 75080, USA.
| | - Stuart F Cogan
- Department of Bioengineering, The University of Texas at Dallas, 800W. Campbell Rd., Richardson, TX 75080, USA.
| | - Victor D Varner
- Department of Bioengineering, The University of Texas at Dallas, 800W. Campbell Rd., Richardson, TX 75080, USA.
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, 800W. Campbell Rd., Richardson, TX 75080, USA.
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Shepherd RK, Villalobos J, Burns O, Nayagam DAX. The development of neural stimulators: a review of preclinical safety and efficacy studies. J Neural Eng 2018; 15:041004. [PMID: 29756600 PMCID: PMC6049833 DOI: 10.1088/1741-2552/aac43c] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Given the rapid expansion of the field of neural stimulation and the rigorous regulatory approval requirements required before these devices can be applied clinically, it is important that there is clarity around conducting preclinical safety and efficacy studies required for the development of this technology. APPROACH The present review examines basic design principles associated with the development of a safe neural stimulator and describes the suite of preclinical safety studies that need to be considered when taking a device to clinical trial. MAIN RESULTS Neural stimulators are active implantable devices that provide therapeutic intervention, sensory feedback or improved motor control via electrical stimulation of neural or neuro-muscular tissue in response to trauma or disease. Because of their complexity, regulatory bodies classify these devices in the highest risk category (Class III), and they are therefore required to go through a rigorous regulatory approval process before progressing to market. The successful development of these devices is achieved through close collaboration across disciplines including engineers, scientists and a surgical/clinical team, and the adherence to clear design principles. Preclinical studies form one of several key components in the development pathway from concept to product release of neural stimulators. Importantly, these studies provide iterative feedback in order to optimise the final design of the device. Key components of any preclinical evaluation include: in vitro studies that are focussed on device reliability and include accelerated testing under highly controlled environments; in vivo studies using animal models of the disease or injury in order to assess efficacy and, given an appropriate animal model, the safety of the technology under both passive and electrically active conditions; and human cadaver and ex vivo studies designed to ensure the device's form factor conforms to human anatomy, to optimise the surgical approach and to develop any specialist surgical tooling required. SIGNIFICANCE The pipeline from concept to commercialisation of these devices is long and expensive; careful attention to both device design and its preclinical evaluation will have significant impact on the duration and cost associated with taking a device through to commercialisation. Carefully controlled in vitro and in vivo studies together with ex vivo and human cadaver trials are key components of a thorough preclinical evaluation of any new neural stimulator.
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Affiliation(s)
- Robert K Shepherd
- Bionics Institute, East Melbourne, Australia. Medical Bionics Department, University of Melbourne, Melbourne, Australia
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Won SM, Song E, Zhao J, Li J, Rivnay J, Rogers JA. Recent Advances in Materials, Devices, and Systems for Neural Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1800534. [PMID: 29855089 DOI: 10.1002/adma.201800534] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 02/28/2018] [Indexed: 06/08/2023]
Abstract
Technologies capable of establishing intimate, long-lived optical/electrical interfaces to neural systems will play critical roles in neuroscience research and in the development of nonpharmacological treatments for neurological disorders. The development of high-density interfaces to 3D populations of neurons across entire tissue systems in living animals, including human subjects, represents a grand challenge for the field, where advanced biocompatible materials and engineered structures for electrodes and light emitters will be essential. This review summarizes recent progress in these directions, with an emphasis on the most promising demonstrated concepts, materials, devices, and systems. The article begins with an overview of electrode materials with enhanced electrical and/or mechanical performance, in forms ranging from planar films, to micro/nanostructured surfaces, to 3D porous frameworks and soft composites. Subsequent sections highlight integration with active materials and components for multiplexed addressing, local amplification, wireless data transmission, and power harvesting, with multimodal operation in soft, shape-conformal systems. These advances establish the foundations for scalable architectures in optical/electrical neural interfaces of the future, where a blurring of the lines between biotic and abiotic systems will catalyze profound progress in neuroscience research and in human health/well-being.
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Affiliation(s)
- Sang Min Won
- Department of Electrical and Computer Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Urbana, IL, 61801, USA
| | - Enming Song
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Northwestern University, Evanston, IL, 60208, USA
| | - Jianing Zhao
- Department of Mechanical Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Urbana, IL, 61801, USA
| | - Jinghua Li
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Northwestern University, Evanston, IL, 60208, USA
| | - Jonathan Rivnay
- Department of Biomedical Engineering, Simpson Querrey Institute for Nanobiotechnology, Northwestern University, Evanston, IL, 60208, USA
| | - John A Rogers
- Center for Bio-Integrated Electronics, Department of Materials Science and Engineering, Biomedical Engineering, Chemistry, Mechanical Engineering, Electrical Engineering and Computer Science, and Neurological Surgery, Simpson Querrey Institute for Nano/biotechnology, McCormick School of Engineering and Feinberg School of Medicine, Northwestern University, Evanston, IL, 60208, USA
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28
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Shoffstall AJ, Capadona JR. Bioinspired materials and systems for neural interfacing. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2018. [DOI: 10.1016/j.cobme.2018.05.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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29
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Prospects for a Robust Cortical Recording Interface. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00028-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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30
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Pancrazio JJ, Deku F, Ghazavi A, Stiller AM, Rihani R, Frewin CL, Varner VD, Gardner TJ, Cogan SF. Thinking Small: Progress on Microscale Neurostimulation Technology. Neuromodulation 2017; 20:745-752. [PMID: 29076214 PMCID: PMC5943060 DOI: 10.1111/ner.12716] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/28/2017] [Accepted: 09/19/2017] [Indexed: 01/08/2023]
Abstract
OBJECTIVES Neural stimulation is well-accepted as an effective therapy for a wide range of neurological disorders. While the scale of clinical devices is relatively large, translational, and pilot clinical applications are underway for microelectrode-based systems. Microelectrodes have the advantage of stimulating a relatively small tissue volume which may improve selectivity of therapeutic stimuli. Current microelectrode technology is associated with chronic tissue response which limits utility of these devices for neural recording and stimulation. One approach for addressing the tissue response problem may be to reduce physical dimensions of the device. "Thinking small" is a trend for the electronics industry, and for implantable neural interfaces, the result may be a device that can evade the foreign body response. MATERIALS AND METHODS This review paper surveys our current understanding pertaining to the relationship between implant size and tissue response and the state-of-the-art in ultrasmall microelectrodes. A comprehensive literature search was performed using PubMed, Web of Science (Clarivate Analytics), and Google Scholar. RESULTS The literature review shows recent efforts to create microelectrodes that are extremely thin appear to reduce or even eliminate the chronic tissue response. With high charge capacity coatings, ultramicroelectrodes fabricated from emerging polymers, and amorphous silicon carbide appear promising for neurostimulation applications. CONCLUSION We envision the emergence of robust and manufacturable ultramicroelectrodes that leverage advanced materials where the small cross-sectional geometry enables compliance within tissue. Nevertheless, future testing under in vivo conditions is particularly important for assessing the stability of thin film devices under chronic stimulation.
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Affiliation(s)
- Joseph J. Pancrazio
- Department of Bioengineering, 800 W. Campbell Road, BSB 13.633, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Felix Deku
- Department of Bioengineering, 800 W. Campbell Road, BSB 13.633, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Atefeh Ghazavi
- Department of Bioengineering, 800 W. Campbell Road, BSB 13.633, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Allison M. Stiller
- Department of Bioengineering, 800 W. Campbell Road, BSB 13.633, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Rashed Rihani
- Department of Bioengineering, 800 W. Campbell Road, BSB 13.633, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Christopher L. Frewin
- Department of Bioengineering, 800 W. Campbell Road, BSB 13.633, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Victor D. Varner
- Department of Bioengineering, 800 W. Campbell Road, BSB 13.633, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | | | - Stuart F. Cogan
- Department of Bioengineering, 800 W. Campbell Road, BSB 13.633, The University of Texas at Dallas, Richardson, TX, 75080, USA
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31
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Vomero M, Castagnola E, Ordonez JS, Carli S, Zucchini E, Maggiolini E, Gueli C, Goshi N, Ciarpella F, Cea C, Fadiga L, Ricci D, Kassegne S, Stieglitz T. Incorporation of Silicon Carbide and Diamond‐Like Carbon as Adhesion Promoters Improves In Vitro and In Vivo Stability of Thin‐Film Glassy Carbon Electrocorticography Arrays. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/adbi.201700081] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Maria Vomero
- Institute of Microsystem Technology (IMTEK) Laboratory for Biomedical Microtechnology Georges‐Koehler‐Allee 102 D‐79110 Freiburg Germany
- Cluster of Excellence BrainLinks‐BrainTools Georges‐Koehler‐Allee 80 79110 Freiburg Germany
| | - Elisa Castagnola
- MEMS Research Laboratory Department of Mechanical Engineering College of Engineering San Diego State University 5500 Campanile Drive San Diego CA 92182‐1323 USA
- Center for Sensorimotor Neural Engineering (CSNE) Box 37, 1414 NE 42nd St., Suite 204 Seattle WA 98105–6271 USA
| | - Juan S. Ordonez
- Institute of Microsystem Technology (IMTEK) Laboratory for Biomedical Microtechnology Georges‐Koehler‐Allee 102 D‐79110 Freiburg Germany
| | - Stefano Carli
- Center for Translational Neurophysiology of Speech and Communication Istituto Italiano di Tecnologia Via Fossato di Mortara 17/19 44121 Ferrara Italy
| | - Elena Zucchini
- Center for Translational Neurophysiology of Speech and Communication Istituto Italiano di Tecnologia Via Fossato di Mortara 17/19 44121 Ferrara Italy
| | - Emma Maggiolini
- Center for Translational Neurophysiology of Speech and Communication Istituto Italiano di Tecnologia Via Fossato di Mortara 17/19 44121 Ferrara Italy
| | - Calogero Gueli
- Institute of Microsystem Technology (IMTEK) Laboratory for Biomedical Microtechnology Georges‐Koehler‐Allee 102 D‐79110 Freiburg Germany
| | - Noah Goshi
- MEMS Research Laboratory Department of Mechanical Engineering College of Engineering San Diego State University 5500 Campanile Drive San Diego CA 92182‐1323 USA
- Center for Sensorimotor Neural Engineering (CSNE) Box 37, 1414 NE 42nd St., Suite 204 Seattle WA 98105–6271 USA
| | - Francesca Ciarpella
- Center for Translational Neurophysiology of Speech and Communication Istituto Italiano di Tecnologia Via Fossato di Mortara 17/19 44121 Ferrara Italy
| | - Claudia Cea
- MEMS Research Laboratory Department of Mechanical Engineering College of Engineering San Diego State University 5500 Campanile Drive San Diego CA 92182‐1323 USA
- Center for Sensorimotor Neural Engineering (CSNE) Box 37, 1414 NE 42nd St., Suite 204 Seattle WA 98105–6271 USA
| | - Luciano Fadiga
- Center for Translational Neurophysiology of Speech and Communication Istituto Italiano di Tecnologia Via Fossato di Mortara 17/19 44121 Ferrara Italy
- Section of Human Physiology University of Ferrara Via Fossato di Mortara 17/19 44121 Ferrara Italy
| | - Davide Ricci
- Center for Translational Neurophysiology of Speech and Communication Istituto Italiano di Tecnologia Via Fossato di Mortara 17/19 44121 Ferrara Italy
| | - Sam Kassegne
- MEMS Research Laboratory Department of Mechanical Engineering College of Engineering San Diego State University 5500 Campanile Drive San Diego CA 92182‐1323 USA
- Center for Sensorimotor Neural Engineering (CSNE) Box 37, 1414 NE 42nd St., Suite 204 Seattle WA 98105–6271 USA
| | - Thomas Stieglitz
- Institute of Microsystem Technology (IMTEK) Laboratory for Biomedical Microtechnology Georges‐Koehler‐Allee 102 D‐79110 Freiburg Germany
- Cluster of Excellence BrainLinks‐BrainTools Georges‐Koehler‐Allee 80 79110 Freiburg Germany
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Diaz-Botia CA, Luna LE, Neely RM, Chamanzar M, Carraro C, Carmena JM, Sabes PN, Maboudian R, Maharbiz MM. A silicon carbide array for electrocorticography and peripheral nerve recording. J Neural Eng 2017; 14:056006. [PMID: 28573982 DOI: 10.1088/1741-2552/aa7698] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Current neural probes have a limited device lifetime of a few years. Their common failure mode is the degradation of insulating films and/or the delamination of the conductor-insulator interfaces. We sought to develop a technology that does not suffer from such limitations and would be suitable for chronic applications with very long device lifetimes. APPROACH We developed a fabrication method that integrates polycrystalline conductive silicon carbide with insulating silicon carbide. The technology employs amorphous silicon carbide as the insulator and conductive silicon carbide at the recording sites, resulting in a seamless transition between doped and amorphous regions of the same material, eliminating heterogeneous interfaces prone to delamination. Silicon carbide has outstanding chemical stability, is biocompatible, is an excellent molecular barrier and is compatible with standard microfabrication processes. MAIN RESULTS We have fabricated silicon carbide electrode arrays using our novel fabrication method. We conducted in vivo experiments in which electrocorticography recordings from the primary visual cortex of a rat were obtained and were of similar quality to those of polymer based electrocorticography arrays. The silicon carbide electrode arrays were also used as a cuff electrode wrapped around the sciatic nerve of a rat to record the nerve response to electrical stimulation. Finally, we demonstrated the outstanding long term stability of our insulating silicon carbide films through accelerated aging tests. SIGNIFICANCE Clinical translation in neural engineering has been slowed in part due to the poor long term performance of current probes. Silicon carbide devices are a promising technology that may accelerate this transition by enabling truly chronic applications.
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Affiliation(s)
- C A Diaz-Botia
- University of California-Berkeley and University of California-San Francisco Graduate group in Bioengineering, CA, United States of America
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