1
|
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.
Collapse
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
| |
Collapse
|
2
|
Hu Z, Niu Q, Hsiao BS, Yao X, Zhang Y. Bioactive polymer-enabled conformal neural interface and its application strategies. MATERIALS HORIZONS 2023; 10:808-828. [PMID: 36597872 DOI: 10.1039/d2mh01125e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Neural interface is a powerful tool to control the varying neuron activities in the brain, where the performance can directly affect the quality of recording neural signals and the reliability of in vivo connection between the brain and external equipment. Recent advances in bioelectronic innovation have provided promising pathways to fabricate flexible electrodes by integrating electrodes on bioactive polymer substrates. These bioactive polymer-based electrodes can enable the conformal contact with irregular tissue and result in low inflammation when compared to conventional rigid inorganic electrodes. In this review, we focus on the use of silk fibroin and cellulose biopolymers as well as certain synthetic polymers to offer the desired flexibility for constructing electrode substrates for a conformal neural interface. First, the development of a neural interface is reviewed, and the signal recording methods and tissue response features of the implanted electrodes are discussed in terms of biocompatibility and flexibility of corresponding neural interfaces. Following this, the material selection, structure design and integration of conformal neural interfaces accompanied by their effective applications are described. Finally, we offer our perspectives on the evolution of desired bioactive polymer-enabled neural interfaces, regarding the biocompatibility, electrical properties and mechanical softness.
Collapse
Affiliation(s)
- Zhanao Hu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, People's Republic of China.
| | - Qianqian Niu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, People's Republic of China.
| | - Benjamin S Hsiao
- Department of Chemistry, Stony Brook University, Stony Brook, New York, 11794-3400, USA
| | - Xiang Yao
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, People's Republic of China.
| | - Yaopeng Zhang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, People's Republic of China.
| |
Collapse
|
3
|
Towards clinical application of implantable brain-computer interfaces for people with late-stage ALS: medical and ethical considerations. J Neurol 2023; 270:1323-1336. [PMID: 36450968 PMCID: PMC9971103 DOI: 10.1007/s00415-022-11464-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 12/05/2022]
Abstract
Individuals with amyotrophic lateral sclerosis (ALS) frequently develop speech and communication problems in the course of their disease. Currently available augmentative and alternative communication technologies do not present a solution for many people with advanced ALS, because these devices depend on residual and reliable motor activity. Brain-computer interfaces (BCIs) use neural signals for computer control and may allow people with late-stage ALS to communicate even when conventional technology falls short. Recent years have witnessed fast progression in the development and validation of implanted BCIs, which place neural signal recording electrodes in or on the cortex. Eventual widespread clinical application of implanted BCIs as an assistive communication technology for people with ALS will have significant consequences for their daily life, as well as for the clinical management of the disease, among others because of the potential interaction between the BCI and other procedures people with ALS undergo, such as tracheostomy. This article aims to facilitate responsible real-world implementation of implanted BCIs. We review the state of the art of research on implanted BCIs for communication, as well as the medical and ethical implications of the clinical application of this technology. We conclude that the contribution of all BCI stakeholders, including clinicians of the various ALS-related disciplines, will be needed to develop procedures for, and shape the process of, the responsible clinical application of implanted BCIs.
Collapse
|
4
|
Go GT, Lee Y, Seo DG, Lee TW. Organic Neuroelectronics: From Neural Interfaces to Neuroprosthetics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2201864. [PMID: 35925610 DOI: 10.1002/adma.202201864] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 07/17/2022] [Indexed: 06/15/2023]
Abstract
Requirements and recent advances in research on organic neuroelectronics are outlined herein. Neuroelectronics such as neural interfaces and neuroprosthetics provide a promising approach to diagnose and treat neurological diseases. However, the current neural interfaces are rigid and not biocompatible, so they induce an immune response and deterioration of neural signal transmission. Organic materials are promising candidates for neural interfaces, due to their mechanical softness, excellent electrochemical properties, and biocompatibility. Also, organic nervetronics, which mimics functional properties of the biological nerve system, is being developed to overcome the limitations of the complex and energy-consuming conventional neuroprosthetics that limit long-term implantation and daily-life usage. Examples of organic materials for neural interfaces and neural signal recordings are reviewed, recent advances of organic nervetronics that use organic artificial synapses are highlighted, and then further requirements for neuroprosthetics are discussed. Finally, the future challenges that must be overcome to achieve ideal organic neuroelectronics for next-generation neuroprosthetics are discussed.
Collapse
Affiliation(s)
- Gyeong-Tak Go
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Yeongjun Lee
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Dae-Gyo Seo
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Tae-Woo Lee
- Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- Institute of Engineering Research, Research Institute of Advanced Materials, Soft Foundry, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
- School of Chemical and Biological Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| |
Collapse
|
5
|
Jun BO, Kim H, Heo SJ, Kim J, Yang JH, Kim S, Kim K, Jin W, Choi J, Jang JE. Miniaturized Self-Resonant Micro Coil Array with A Floating Structure for Wireless Multi-Channel Transmission. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2102944. [PMID: 34716695 PMCID: PMC8693062 DOI: 10.1002/advs.202102944] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/16/2021] [Indexed: 06/13/2023]
Abstract
Micro size antennas have significant merits due to the small size effect, enabling new device concepts. However, the low-quality factor (Q-factor), the large size of impedance matching components, and the poor selectivity of the multi-array design remain challenging issues. To solve these issues, a floating coil structure stacked on a loop micro-antenna is suggested. Various floating coil designs are prepared with appropriate matching conditions at specific target frequencies, using an easy fabrication process without the need for additional space. A simple one-loop antenna design shows a higher Q-factor than other, more complicated designs. The micro-sized loop antenna with the 80 µm trace width design exhibits the highest Q-factor, around 31 within 7 GHz. The 8 different floating coil designs result in high-frequency selectivity from 1 to 7 GHz. The highest selectivity contrast and WPT efficiency are above 7 and around 1%, respectively. Considering the size of the antenna, the efficiency is not low, mainly due to the good matching effect with the high Q-factor of the floating coil and the loop antenna. This micro-antenna array concept with high integration density can be applied for advanced wireless neural stimulation or in wireless pixel array concepts in flexible displays.
Collapse
Affiliation(s)
- Byoung Ok Jun
- Department of Information and Communication EngineeringDaegu Gyeongbuk Institute of Science & Technology (DGIST)Daegu711–873Korea
| | - Han‐Joon Kim
- Department of Electrical and Computer EngineeringNational University of SingaporeSingapore119077Singapore
| | - Su Jin Heo
- Department of Information and Communication EngineeringDaegu Gyeongbuk Institute of Science & Technology (DGIST)Daegu711–873Korea
| | - Jonghyeun Kim
- Department of Information and Communication EngineeringDaegu Gyeongbuk Institute of Science & Technology (DGIST)Daegu711–873Korea
| | - Jae Hoon Yang
- Department of Information and Communication EngineeringDaegu Gyeongbuk Institute of Science & Technology (DGIST)Daegu711–873Korea
| | - Seunguk Kim
- Department of Information and Communication EngineeringDaegu Gyeongbuk Institute of Science & Technology (DGIST)Daegu711–873Korea
| | - Kyungtae Kim
- Department of Information and Communication EngineeringDaegu Gyeongbuk Institute of Science & Technology (DGIST)Daegu711–873Korea
| | - Woo‐Cheol Jin
- Department of Information and Communication EngineeringDaegu Gyeongbuk Institute of Science & Technology (DGIST)Daegu711–873Korea
| | - Ji‐Woong Choi
- Department of Information and Communication EngineeringDaegu Gyeongbuk Institute of Science & Technology (DGIST)Daegu711–873Korea
| | - Jae Eun Jang
- Department of Information and Communication EngineeringDaegu Gyeongbuk Institute of Science & Technology (DGIST)Daegu711–873Korea
| |
Collapse
|
6
|
Fernández E, Alfaro A, Soto-Sánchez C, González-López P, Lozano Ortega AM, Peña S, Grima MD, Rodil A, Gómez B, Chen X, Roelfsema PR, Rolston JD, Davis TS, Normann RA. Visual percepts evoked with an Intracortical 96-channel microelectrode array inserted in human occipital cortex. J Clin Invest 2021; 131:151331. [PMID: 34665780 DOI: 10.1172/jci151331] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 09/28/2021] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND A long-held dream of scientists is to transfer information directly to the visual cortex of blind individuals, thereby restoring a rudimentary form of sight. However, no clinically available cortical visual prosthesis yet exists. METHODS We implanted an intracortical microelectrode array consisting of 96 electrodes in the visual cortex of a 57-year-old person with complete blindness for a six- month period. We measured thresholds and the characteristics of the visual percepts elicited by intracortical microstimulation. RESULTS Implantation and subsequent explantation of intracortical microelectrodes were carried out without complications. The mean stimulation threshold for single electrodes was 66.8 ± 36.5 μA. We consistently obtained high-quality recordings from visually deprived neurons and the stimulation parameters remained stable over time. Simultaneous stimulation via multiple electrodes were associated with a significant reduction in thresholds (p<0.001, ANOVA test) and evoked discriminable phosphene percepts, allowing the blind participant to identify some letters and recognize object boundaries. Furthermore, we observed a learning process that helped the subject to recognize complex patterns over time. CONCLUSIONS Our results demonstrate the safety and efficacy of chronic intracortical microstimulation via a large number of electrodes in human visual cortex, showing its high potential for restoring functional vision in the blind. TRIAL REGISTRATION ClinicalTrials.gov identifier NCT02983370. FUNDING Funding was provided by grant RTI2018-098969-B-100 from the Spanish Ministerio de Ciencia Innovación y Universidades, by grant PROMETEO/2019/119 from the Generalitat Valenciana (Spain), by the Bidons Egara Research Chair of the University Miguel Hernández (Spain) and by the John Moran Eye Center of the University of Utah (US).
Collapse
Affiliation(s)
| | - Arantxa Alfaro
- Servicio de Neurología, Hospital Vega Baja, Elche, Spain
| | | | - Pablo González-López
- Servicio de Neurología, Hospital General Universitario de Alicante, Alicante, Spain
| | | | - Sebastian Peña
- Bioengineering Institute, University Miguel Hernandez, Elche, Spain
| | | | - Alfonso Rodil
- Bioengineering Institute, University Miguel Hernandez, Elche, Spain
| | - Bernardeta Gómez
- Bioengineering Institute, University Miguel Hernandez, Elche, Spain
| | - Xing Chen
- Department of Vision & Cognition, Netherland Institute for Neuroscience, Amsterdam, Netherlands
| | - Pieter R Roelfsema
- Department of Vision & Cognition, Netherland Institute for Neuroscience, Amsterdam, Netherlands
| | - John D Rolston
- Department of Neurosurgery and Biomedical Engineering, University of Utah, Salt Lake City, United States of America
| | - Tyler S Davis
- Department of Neurosurgery and Biomedical Engineering, University of Utah, Salt Lake City, United States of America
| | - Richard A Normann
- John Moran Eye Center and Biomedical Engineering, University of Utah, Salt Lake City, United States of America
| |
Collapse
|
7
|
Yang W, Gong Y, Li W. A Review: Electrode and Packaging Materials for Neurophysiology Recording Implants. Front Bioeng Biotechnol 2021; 8:622923. [PMID: 33585422 PMCID: PMC7873964 DOI: 10.3389/fbioe.2020.622923] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/10/2020] [Indexed: 01/28/2023] Open
Abstract
To date, a wide variety of neural tissue implants have been developed for neurophysiology recording from living tissues. An ideal neural implant should minimize the damage to the tissue and perform reliably and accurately for long periods of time. Therefore, the materials utilized to fabricate the neural recording implants become a critical factor. The materials of these devices could be classified into two broad categories: electrode materials as well as packaging and substrate materials. In this review, inorganic (metals and semiconductors), organic (conducting polymers), and carbon-based (graphene and carbon nanostructures) electrode materials are reviewed individually in terms of various neural recording devices that are reported in recent years. Properties of these materials, including electrical properties, mechanical properties, stability, biodegradability/bioresorbability, biocompatibility, and optical properties, and their critical importance to neural recording quality and device capabilities, are discussed. For the packaging and substrate materials, different material properties are desired for the chronic implantation of devices in the complex environment of the body, such as biocompatibility and moisture and gas hermeticity. This review summarizes common solid and soft packaging materials used in a variety of neural interface electrode designs, as well as their packaging performances. Besides, several biopolymers typically applied over the electrode package to reinforce the mechanical rigidity of devices during insertion, or to reduce the immune response and inflammation at the device-tissue interfaces are highlighted. Finally, a benchmark analysis of the discussed materials and an outlook of the future research trends are concluded.
Collapse
Affiliation(s)
| | | | - Wen Li
- Microtechnology Lab, Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI, United States
| |
Collapse
|
8
|
Baek DH, Ahn S, Kim HS, Kim DW. Fabrication of Donut-Type Neural Electrode for Visual Information as Well as Surface Electrical Stimulation. J Med Biol Eng 2020. [DOI: 10.1007/s40846-020-00540-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
9
|
Shah AR, Khan MS, Hirahara AM, Lange M, Ranjan R, Dosdall DJ. In Vitro/Ex Vivo Investigation of Modified Utah Electrode Array to Selectively Sense and Pace the Sub-Surface Cardiac His Bundle. ACS Biomater Sci Eng 2020; 6:3335-3348. [PMID: 32715084 DOI: 10.1021/acsbiomaterials.0c00065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Utah Electrode Arrays (UEAs) have previously been characterized and implanted for neural recordings and stimulation at relatively low current levels. This proof-of-concept study investigated the applicability of UEAs in sub-surface cardiac pacing, for the first time, particularly to selectively sense and pace the His-Bundle (HB). HB pacing produces synchronous ventricular depolarization and improved cardiac function. Modified UEAs with sputtered iridium oxide film (SIROF) tips (100 - 150 μm) were characterized for SIROF delamination using an electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and voltage transient (VT) techniques at various current levels of up to 8 mA for a biphasic pulse with 1 ms duration per phase at 4 Hz. Our results indicate that at a short pacing duration of 20 s with current levels of up to 4 mA, the SIROF exhibited a strong charge-transfer performance. For the longer pacing duration (6 min), SIROF demonstrated its holding capacity at all current levels except for ≥2 mA when delamination commenced for the time exceeded 4 min (EIS) and 2 min (VT). UEAs were inserted in isolated, perfused goat hearts to record the HB electrograms in real-time. Both stimulated and unstimulated electrodes were characterized for SIROF delamination before, during and after in vivo work. Our findings indicate that UEA was stable during the heart's contraction and relaxation phase. Further, at a short pacing duration with current levels of up to 4 mA, UEA demonstrated high selectively in sensing the HB. This proof-of-concept work demonstrates the potential applicability of UEAs in cardiac applications.
Collapse
Affiliation(s)
- Ankur R Shah
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Muhammad S Khan
- Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Annie M Hirahara
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Matthias Lange
- Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA
| | - Ravi Ranjan
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA.,Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Utah, Salt Lake City, UT 84112, USA
| | - Derek J Dosdall
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT 84112, USA.,Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84112, USA.,Division of Cardiovascular Medicine, Department of Internal Medicine, The University of Utah, Salt Lake City, UT 84112, USA.,Division of Cardiothoracic Surgery, Department of Surgery, The University of Utah, Salt Lake City, UT 84112, USA
| |
Collapse
|
10
|
Abstract
Locked-in syndrome (LIS) is characterized by an inability to move or speak in the presence of intact cognition and can be caused by brainstem trauma or neuromuscular disease. Quality of life (QoL) in LIS is strongly impaired by the inability to communicate, which cannot always be remedied by traditional augmentative and alternative communication (AAC) solutions if residual muscle activity is insufficient to control the AAC device. Brain-computer interfaces (BCIs) may offer a solution by employing the person's neural signals instead of relying on muscle activity. Here, we review the latest communication BCI research using noninvasive signal acquisition approaches (electroencephalography, functional magnetic resonance imaging, functional near-infrared spectroscopy) and subdural and intracortical implanted electrodes, and we discuss current efforts to translate research knowledge into usable BCI-enabled communication solutions that aim to improve the QoL of individuals with LIS.
Collapse
|
11
|
Ferguson M, Sharma D, Ross D, Zhao F. A Critical Review of Microelectrode Arrays and Strategies for Improving Neural Interfaces. Adv Healthc Mater 2019; 8:e1900558. [PMID: 31464094 PMCID: PMC6786932 DOI: 10.1002/adhm.201900558] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/25/2019] [Indexed: 12/19/2022]
Abstract
Though neural interface systems (NISs) can provide a potential solution for mitigating the effects of limb loss and central nervous system damage, the microelectrode array (MEA) component of NISs remains a significant limiting factor to their widespread clinical applications. Several strategies can be applied to MEA designs to increase their biocompatibility. Herein, an overview of NISs and their applications is provided, along with a detailed discussion of strategies for alleviating the foreign body response (FBR) and abnormalities seen at the interface of MEAs and the brain tissue following MEA implantation. Various surface modifications, including natural/synthetic surface coatings, hydrogels, and topography alterations, have shown to be highly successful in improving neural cell adhesion, reducing gliosis, and increasing MEA longevity. Different MEA surface geometries, such as those seen in the Utah and Michigan arrays, can help alleviate the resultant FBR by reducing insertion damage, while providing new avenues for improving MEA recording performance and resolution. Increasing overall flexibility of MEAs as well as reducing their stiffness is also shown to reduce MEA induced micromotion along with FBR severity. By combining multiple different properties into a single MEA, the severity and duration of an FBR postimplantation can be reduced substantially.
Collapse
Affiliation(s)
- Morgan Ferguson
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| | - Dhavan Sharma
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| | - David Ross
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| | - Feng Zhao
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| |
Collapse
|
12
|
Cheng MY, Damalerio RB, Chen W, Rajkumar R, Dawe GS. Ultracompact Multielectrode Array for Neurological Monitoring. SENSORS 2019; 19:s19102286. [PMID: 31108970 PMCID: PMC6567369 DOI: 10.3390/s19102286] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/08/2019] [Accepted: 05/08/2019] [Indexed: 02/01/2023]
Abstract
Patients with paralysis, spinal cord injury, or amputated limbs could benefit from using brain–machine interface technology for communication and neurorehabilitation. In this study, a 32-channel three-dimensional (3D) multielectrode probe array was developed for the neural interface system of a brain–machine interface to monitor neural activity. A novel microassembly technique involving lead transfer was used to prevent misalignment in the bonding plane during the orthogonal assembly of the 3D multielectrode probe array. Standard microassembly and biopackaging processes were utilized to implement the proposed lead transfer technique. The maximum profile of the integrated 3D neural device was set to 0.50 mm above the pia mater to reduce trauma to brain cells. Benchtop tests characterized the electrical impedance of the neural device. A characterization test revealed that the impedance of the 3D multielectrode probe array was on average approximately 0.55 MΩ at a frequency of 1 KHz. Moreover, in vitro cytotoxicity tests verified the biocompatibility of the device. Subsequently, 3D multielectrode probe arrays were implanted in rats and exhibited the capability to record local field potentials and spike signals.
Collapse
Affiliation(s)
- Ming-Yuan Cheng
- Institute of Microelectronics, Agency for Science, Technology and Research, Singapore 138634, Singapore.
| | - Ramona B Damalerio
- Institute of Microelectronics, Agency for Science, Technology and Research, Singapore 138634, Singapore.
| | - Weiguo Chen
- Institute of Microelectronics, Agency for Science, Technology and Research, Singapore 138634, Singapore.
| | - Ramamoorthy Rajkumar
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore 117600, Singapore.
| | - Gavin S Dawe
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore 117600, Singapore.
| |
Collapse
|
13
|
Advances in Penetrating Multichannel Microelectrodes Based on the Utah Array Platform. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1101:1-40. [PMID: 31729670 DOI: 10.1007/978-981-13-2050-7_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The Utah electrode array (UEA) and its many derivatives have become a gold standard for high-channel count bi-directional neural interfaces, in particular in human subject applications. The chapter provides a brief overview of leading electrode concepts and the context in which the UEA has to be understood. It goes on to discuss the key advances and developments of the UEA platform in the past 15 years, as well as novel wireless and system integration technologies that will merge into future generations of fully integrated devices. Aspects covered include novel device architectures that allow scaling of channel count and density of electrode contacts, material improvements to substrate, electrode contacts, and encapsulation. Further subjects are adaptations of the UEA platform to support IR and optogenetic simulation as well as an improved understanding of failure modes and methods to test and accelerate degradation in vitro such as to better predict device failure and lifetime in vivo.
Collapse
|
14
|
Abstract
This paper presents a multidisciplinary experiment where a population of neurons, dissociated from rat hippocampi, has been cultivated over a CMOS-based micro-electrode array (MEA) and its electrical activity has been detected and mapped by an advanced spike-sorting algorithm implemented on FPGA. MEAs are characterized by low signal-to-noise ratios caused by both the contactless sensing of weak extracellular voltages and the high noise power coming from cells and analog electronics signal processing. This low SNR forces to utilize advanced noise rejection algorithms to separate relevant neural activity from noise, which are usually implemented via software/off-line. However, off-line detection of neural spikes cannot be obviously used for real-time electrical stimulation. In this scenario, this paper presents a proper FPGA-based system capable to detect in real-time neural spikes from background noise. The output signals of the proposed system provide real-time spatial and temporal information about the culture electrical activity and the noise power distribution with a minimum latency of 165 ns. The output bit-stream can be further utilized to detect synchronous activity within the neural network.
Collapse
|
15
|
Mitrasinovic S, Brown AP, Schaefer AT, Chang SD, Appelboom G. Silicon Valley new focus on brain computer interface: hype or hope for new applications? F1000Res 2018; 7:1327. [PMID: 30705750 PMCID: PMC6343225 DOI: 10.12688/f1000research.15726.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/14/2018] [Indexed: 11/28/2022] Open
Abstract
In the last year there has been increasing interest and investment into developing devices to interact with the central nervous system, in particular developing a robust brain-computer interface (BCI). In this article, we review the most recent research advances and the current host of engineering and neurological challenges that must be overcome for clinical application. In particular, space limitations, isolation of targeted structures, replacement of probes following failure, delivery of nanomaterials and processing and understanding recorded data. Neural engineering has developed greatly over the past half-century, which has allowed for the development of better neural recording techniques and clinical translation of neural interfaces. Implementation of general purpose BCIs face a number of constraints arising from engineering, computational, ethical and neuroscientific factors that still have to be addressed. Electronics have become orders of magnitude smaller and computationally faster than neurons, however there is much work to be done in decoding the neural circuits. New interest and funding from the non-medical community may be a welcome catalyst for focused research and development; playing an important role in future advancements in the neuroscience community.
Collapse
Affiliation(s)
| | | | - Andreas T. Schaefer
- The Francis Crick Institute, London, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Steven D. Chang
- Department of Neurosurgery, Stanford University Medical Center, Brighton, USA
| | - Geoff Appelboom
- Department of Neurosurgery, Stanford University Medical Center, Brighton, USA
- Byers Center for Biodesign, Stanford University School of Medicine, Brighton, USA
| |
Collapse
|
16
|
Advances in Materials for Recent Low-Profile Implantable Bioelectronics. MATERIALS 2018; 11:ma11040522. [PMID: 29596359 PMCID: PMC5951368 DOI: 10.3390/ma11040522] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 03/20/2018] [Accepted: 03/26/2018] [Indexed: 12/28/2022]
Abstract
The rapid development of micro/nanofabrication technologies to engineer a variety of materials has enabled new types of bioelectronics for health monitoring and disease diagnostics. In this review, we summarize widely used electronic materials in recent low-profile implantable systems, including traditional metals and semiconductors, soft polymers, biodegradable metals, and organic materials. Silicon-based compounds have represented the traditional materials in medical devices, due to the fully established fabrication processes. Examples include miniaturized sensors for monitoring intraocular pressure and blood pressure, which are designed in an ultra-thin diaphragm to react with the applied pressure. These sensors are integrated into rigid circuits and multiple modules; this brings challenges regarding the fundamental material’s property mismatch with the targeted human tissues, which are intrinsically soft. Therefore, many polymeric materials have been investigated for hybrid integration with well-characterized functional materials such as silicon membranes and metal interconnects, which enable soft implantable bioelectronics. The most recent trend in implantable systems uses transient materials that naturally dissolve in body fluid after a programmed lifetime. Such biodegradable metallic materials are advantageous in the design of electronics due to their proven electrical properties. Collectively, this review delivers the development history of materials in implantable devices, while introducing new bioelectronics based on bioresorbable materials with multiple functionalities.
Collapse
|
17
|
Wellman SM, Eles JR, Ludwig KA, Seymour JP, Michelson NJ, McFadden WE, Vazquez AL, Kozai TDY. A Materials Roadmap to Functional Neural Interface Design. ADVANCED FUNCTIONAL MATERIALS 2018; 28:1701269. [PMID: 29805350 PMCID: PMC5963731 DOI: 10.1002/adfm.201701269] [Citation(s) in RCA: 186] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Advancement in neurotechnologies for electrophysiology, neurochemical sensing, neuromodulation, and optogenetics are revolutionizing scientific understanding of the brain while enabling treatments, cures, and preventative measures for a variety of neurological disorders. The grand challenge in neural interface engineering is to seamlessly integrate the interface between neurobiology and engineered technology, to record from and modulate neurons over chronic timescales. However, the biological inflammatory response to implants, neural degeneration, and long-term material stability diminish the quality of interface overtime. Recent advances in functional materials have been aimed at engineering solutions for chronic neural interfaces. Yet, the development and deployment of neural interfaces designed from novel materials have introduced new challenges that have largely avoided being addressed. Many engineering efforts that solely focus on optimizing individual probe design parameters, such as softness or flexibility, downplay critical multi-dimensional interactions between different physical properties of the device that contribute to overall performance and biocompatibility. Moreover, the use of these new materials present substantial new difficulties that must be addressed before regulatory approval for use in human patients will be achievable. In this review, the interdependence of different electrode components are highlighted to demonstrate the current materials-based challenges facing the field of neural interface engineering.
Collapse
Affiliation(s)
- Steven M Wellman
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - James R Eles
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Kip A Ludwig
- Department of Neurologic Surgery, 200 First St. SW, Rochester, MN 55905
| | - John P Seymour
- Electrical & Computer Engineering, 1301 Beal Ave., 2227 EECS, Ann Arbor, MI 48109
| | - Nicholas J Michelson
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - William E McFadden
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Alberto L Vazquez
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Takashi D Y Kozai
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| |
Collapse
|
18
|
Huang X, Denprasert PM, Zhou L, Vest AN, Kohan S, Loeb GE. Accelerated life-test methods and results for implantable electronic devices with adhesive encapsulation. Biomed Microdevices 2018; 19:46. [PMID: 28536859 DOI: 10.1007/s10544-017-0189-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have developed and applied new methods to estimate the functional life of miniature, implantable, wireless electronic devices that rely on non-hermetic, adhesive encapsulants such as epoxy. A comb pattern board with a high density of interdigitated electrodes (IDE) could be used to detect incipient failure from water vapor condensation. Inductive coupling of an RF magnetic field was used to provide DC bias and to detect deterioration of an encapsulated comb pattern. Diodes in the implant converted part of the received energy into DC bias on the comb pattern. The capacitance of the comb pattern forms a resonant circuit with the inductor by which the implant receives power. Any moisture affects both the resonant frequency and the Q-factor of the resonance of the circuitry, which was detected wirelessly by its effects on the coupling between two orthogonal RF coils placed around the device. Various defects were introduced into the comb pattern devices to demonstrate sensitivity to failures and to correlate these signals with visual inspection of failures. Optimized encapsulation procedures were validated in accelerated life tests of both comb patterns and a functional neuromuscular stimulator under development. Strong adhesive bonding between epoxy and electronic circuitry proved to be necessary and sufficient to predict 1 year packaging reliability of 99.97% for the neuromuscular stimulator.
Collapse
Affiliation(s)
- Xuechen Huang
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA. .,General Stim Inc., Los Angeles, CA, USA.
| | | | - Li Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Adriana Nicholson Vest
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Sam Kohan
- General Stim Inc., Los Angeles, CA, USA
| | - Gerald E Loeb
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,General Stim Inc., Los Angeles, CA, USA
| |
Collapse
|
19
|
Affiliation(s)
- James G. Roberts
- North Carolina State University, Department of Chemistry, Raleigh, NC 27695, United States
| | - Leslie A. Sombers
- North Carolina State University, Department of Chemistry, Raleigh, NC 27695, United States
| |
Collapse
|
20
|
Szostak KM, Grand L, Constandinou TG. Neural Interfaces for Intracortical Recording: Requirements, Fabrication Methods, and Characteristics. Front Neurosci 2017; 11:665. [PMID: 29270103 PMCID: PMC5725438 DOI: 10.3389/fnins.2017.00665] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 11/15/2017] [Indexed: 01/30/2023] Open
Abstract
Implantable neural interfaces for central nervous system research have been designed with wire, polymer, or micromachining technologies over the past 70 years. Research on biocompatible materials, ideal probe shapes, and insertion methods has resulted in building more and more capable neural interfaces. Although the trend is promising, the long-term reliability of such devices has not yet met the required criteria for chronic human application. The performance of neural interfaces in chronic settings often degrades due to foreign body response to the implant that is initiated by the surgical procedure, and related to the probe structure, and material properties used in fabricating the neural interface. In this review, we identify the key requirements for neural interfaces for intracortical recording, describe the three different types of probes-microwire, micromachined, and polymer-based probes; their materials, fabrication methods, and discuss their characteristics and related challenges.
Collapse
Affiliation(s)
- Katarzyna M. Szostak
- Next Generation Neural Interfaces Lab, Department of Electrical and Electronic Engineering, Centre for Bio-Inspired Technology, Imperial College London, London, United Kingdom
| | - Laszlo Grand
- Next Generation Neural Interfaces Lab, Department of Electrical and Electronic Engineering, Centre for Bio-Inspired Technology, Imperial College London, London, United Kingdom
- Department of Neurology and Neurosurgery, Johns Hopkins University, Baltimore, MD, United States
| | - Timothy G. Constandinou
- Next Generation Neural Interfaces Lab, Department of Electrical and Electronic Engineering, Centre for Bio-Inspired Technology, Imperial College London, London, United Kingdom
| |
Collapse
|
21
|
Mols K, Musa S, Nuttin B, Lagae L, Bonin V. In vivo characterization of the electrophysiological and astrocytic responses to a silicon neuroprobe implanted in the mouse neocortex. Sci Rep 2017; 7:15642. [PMID: 29142267 PMCID: PMC5688150 DOI: 10.1038/s41598-017-15121-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 10/23/2017] [Indexed: 12/04/2022] Open
Abstract
Silicon neuroprobes hold great potential for studies of large-scale neural activity and brain computer interfaces, but data on brain response in chronic implants is limited. Here we explored with in vivo cellular imaging the response to multisite silicon probes for neural recordings. We tested a chronic implant for mice consisting of a CMOS-compatible silicon probe rigidly implanted in the cortex under a cranial imaging window. Multiunit recordings of cortical neurons with the implant showed no degradation of electrophysiological signals weeks after implantation (mean spike and noise amplitudes of 186 ± 42 µVpp and 16 ± 3.2 µVrms, respectively, n = 5 mice). Two-photon imaging through the cranial window allowed longitudinal monitoring of fluorescently-labeled astrocytes from the second week post implantation for 8 weeks (n = 3 mice). The imaging showed a local increase in astrocyte-related fluorescence that remained stable from the second to the tenth week post implantation. These results demonstrate that, in a standard electrophysiology protocol in mice, rigidly implanted silicon probes can provide good short to medium term chronic recording performance with a limited astrocyte inflammatory response. The precise factors influencing the response to silicon probe implants remain to be elucidated.
Collapse
Affiliation(s)
- Katrien Mols
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001, Leuven, Belgium.,imec, Department of Life Science Technologies, Kapeldreef 75, 3001, Leuven, Belgium.,KU Leuven, Department of Neurosciences, 3000, Leuven, Belgium
| | - Silke Musa
- imec, Department of Life Science Technologies, Kapeldreef 75, 3001, Leuven, Belgium
| | - Bart Nuttin
- KU Leuven, Department of Neurosciences, 3000, Leuven, Belgium
| | - Liesbet Lagae
- imec, Department of Life Science Technologies, Kapeldreef 75, 3001, Leuven, Belgium.,KU Leuven, Department of Physics and Astronomy, 3001, Leuven, Belgium
| | - Vincent Bonin
- Neuro-Electronics Research Flanders, Kapeldreef 75, 3001, Leuven, Belgium. .,Vlaams Instituut voor Biotechnologie (VIB), 3001, Leuven, Belgium. .,KU Leuven, Department of Biology, 3000, Leuven, Belgium.
| |
Collapse
|
22
|
Kao JC, Ryu SI, Shenoy KV. Leveraging neural dynamics to extend functional lifetime of brain-machine interfaces. Sci Rep 2017; 7:7395. [PMID: 28784984 PMCID: PMC5547077 DOI: 10.1038/s41598-017-06029-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/07/2017] [Indexed: 01/09/2023] Open
Abstract
Intracortical brain-machine interfaces (BMIs) aim to restore lost motor function to people with neurological deficits by decoding neural activity into control signals for guiding prostheses. An important challenge facing BMIs is that, over time, the number of neural signals recorded from implanted multielectrode arrays will decline and result in a concomitant decrease of BMI performance. We sought to extend BMI lifetime by developing an algorithmic technique, implemented entirely in software, to improve performance over state-of-the-art algorithms as the number of recorded neural signals decline. Our approach augments the decoder by incorporating neural population dynamics remembered from an earlier point in the array lifetime. We demonstrate, in closed-loop experiments with two rhesus macaques, that after the loss of approximately 60% of recording electrodes, our approach outperforms state-of-the-art decoders by a factor of 3.2× and 1.7× (corresponding to a 46% and 22% recovery of maximal performance). Further, our results suggest that neural population dynamics in motor cortex are invariant to the number of recorded neurons. By extending functional BMI lifetime, this approach increases the clinical viability of BMIs.
Collapse
Affiliation(s)
- Jonathan C Kao
- Department of Electrical Engineering, University of California Los Angeles, Los Angeles, CA, 90095, USA.,Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Stephen I Ryu
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA.,Department of Neurosurgery, Palo Alto Medical Foundation, Palo Alto, CA, 94301, USA
| | - Krishna V Shenoy
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA. .,Department of Neurobiology, Stanford University, Stanford, CA, 94305, USA. .,Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA. .,Neurosciences Program, Stanford University, Stanford, CA, 94305, USA. .,Howard Hughes Medical Institute, Stanford University, Stanford, CA, 94305, USA.
| |
Collapse
|
23
|
Lebedev MA, Nicolelis MAL. Brain-Machine Interfaces: From Basic Science to Neuroprostheses and Neurorehabilitation. Physiol Rev 2017; 97:767-837. [PMID: 28275048 DOI: 10.1152/physrev.00027.2016] [Citation(s) in RCA: 235] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Brain-machine interfaces (BMIs) combine methods, approaches, and concepts derived from neurophysiology, computer science, and engineering in an effort to establish real-time bidirectional links between living brains and artificial actuators. Although theoretical propositions and some proof of concept experiments on directly linking the brains with machines date back to the early 1960s, BMI research only took off in earnest at the end of the 1990s, when this approach became intimately linked to new neurophysiological methods for sampling large-scale brain activity. The classic goals of BMIs are 1) to unveil and utilize principles of operation and plastic properties of the distributed and dynamic circuits of the brain and 2) to create new therapies to restore mobility and sensations to severely disabled patients. Over the past decade, a wide range of BMI applications have emerged, which considerably expanded these original goals. BMI studies have shown neural control over the movements of robotic and virtual actuators that enact both upper and lower limb functions. Furthermore, BMIs have also incorporated ways to deliver sensory feedback, generated from external actuators, back to the brain. BMI research has been at the forefront of many neurophysiological discoveries, including the demonstration that, through continuous use, artificial tools can be assimilated by the primate brain's body schema. Work on BMIs has also led to the introduction of novel neurorehabilitation strategies. As a result of these efforts, long-term continuous BMI use has been recently implicated with the induction of partial neurological recovery in spinal cord injury patients.
Collapse
|
24
|
Ghane Motlagh B, Choueib M, Hajhosseini Mesgar A, Hasanuzzaman M, Sawan M. Direct Growth of Carbon Nanotubes on New High-Density 3D Pyramid-Shaped Microelectrode Arrays for Brain-Machine Interfaces. MICROMACHINES 2016; 7:mi7090163. [PMID: 30404335 PMCID: PMC6189795 DOI: 10.3390/mi7090163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/26/2016] [Accepted: 08/30/2016] [Indexed: 11/29/2022]
Abstract
Silicon micromachined, high-density, pyramid-shaped neural microelectrode arrays (MEAs) have been designed and fabricated for intracortical 3D recording and stimulation. The novel architecture of this MEA has made it unique among the currently available micromachined electrode arrays, as it has provided higher density contacts between the electrodes and targeted neural tissue facilitating recording from different depths of the brain. Our novel masking technique enhances uniform tip-exposure for variable-height electrodes and improves process time and cost significantly. The tips of the electrodes have been coated with platinum (Pt). We have reported for the first time a selective direct growth of carbon nanotubes (CNTs) on the tips of 3D MEAs using the Pt coating as a catalyzer. The average impedance of the CNT-coated electrodes at 1 kHz is 14 kΩ. The CNT coating led to a 5-fold decrease of the impedance and a 600-fold increase in charge transfer compared with the Pt electrode.
Collapse
Affiliation(s)
- Bahareh Ghane Motlagh
- Polystim Neurotechnologies Laboratory, Department of Electrical Engineering, Polytechnique Montreal, Montreal, QC H3C 3A7, Canada.
| | - May Choueib
- Institut Lumière Matière, Université Claude Bernard Lyon 1, CNRS, Univ Lyon, Villeurbanne 69622, France.
| | - Alireza Hajhosseini Mesgar
- Microfabrication Laboratory (LMF), Thin Films Group (GCM), Department of Engineering Physics, Polytechnique Montreal, Montreal, QC H3C 3A7, Canada.
| | - Md Hasanuzzaman
- Polystim Neurotechnologies Laboratory, Department of Electrical Engineering, Polytechnique Montreal, Montreal, QC H3C 3A7, Canada.
| | - Mohamad Sawan
- Polystim Neurotechnologies Laboratory, Department of Electrical Engineering, Polytechnique Montreal, Montreal, QC H3C 3A7, Canada.
| |
Collapse
|
25
|
Yousif A, Kelly SK. Development of high impedance measurement system for water leakage detection in implantable neuroprosthetic devices. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2016:4865-4868. [PMID: 28269360 DOI: 10.1109/embc.2016.7591817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
There has been a push for a greater number of channels in implantable neuroprosthetic devices; but, that number has largely been limited by current hermetic packaging technology. Microfabricated packaging is becoming reality, but a standard testing system is needed to prepare these devices for clinical trials. Impedance measurements of electrodes built into the packaging layers may give an early warning of device failure and predict device lifetime. Because the impedance magnitudes of such devices can be on the order of gigaohms, a versatile system was designed to accommodate ultra-high impedances and allow future integrated circuit implementation in current neural prosthetic technologies. Here we present the circuitry, control software, and preliminary testing results of our designed system.
Collapse
|
26
|
Soltani N, Aliroteh MS, Salam MT, Perez Velazquez JL, Genov R. Low-Radiation Cellular Inductive Powering of Rodent Wireless Brain Interfaces: Methodology and Design Guide. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2016; 10:920-932. [PMID: 26960227 DOI: 10.1109/tbcas.2015.2502840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This paper presents a general methodology of inductive power delivery in wireless chronic rodent electrophysiology applications. The focus is on such systems design considerations under the following key constraints: maximum power delivery under the allowable specific absorption rate (SAR), low cost and spatial scalability. The methodology includes inductive coil design considerations within a low-frequency ferrite-core-free power transfer link which includes a scalable coil-array power transmitter floor and a single-coil implanted or worn power receiver. A specific design example is presented that includes the concept of low-SAR cellular single-transmitter-coil powering through dynamic tracking of a magnet-less receiver spatial location. The transmitter coil instantaneous supply current is monitored using a small number of low-cost electronic components. A drop in its value indicates the proximity of the receiver due to the reflected impedance of the latter. Only the transmitter coil nearest to the receiver is activated. Operating at the low frequency of 1.5 MHz, the inductive powering floor delivers a maximum of 15.9 W below the IEEE C95 SAR limit, which is over three times greater than that in other recently reported designs. The power transfer efficiency of 39% and 13% at the nominal and maximum distances of 8 cm and 11 cm, respectively, is maintained.
Collapse
|
27
|
Enhanced Flexible Tubular Microelectrode with Conducting Polymer for Multi-Functional Implantable Tissue-Machine Interface. Sci Rep 2016; 6:26910. [PMID: 27229174 PMCID: PMC4882553 DOI: 10.1038/srep26910] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/11/2016] [Indexed: 11/08/2022] Open
Abstract
Implantable biomedical microdevices enable the restoration of body function and improvement of health condition. As the interface between artificial machines and natural tissue, various kinds of microelectrodes with high density and tiny size were developed to undertake precise and complex medical tasks through electrical stimulation and electrophysiological recording. However, if only the electrical interaction existed between electrodes and muscle or nerve tissue without nutrition factor delivery, it would eventually lead to a significant symptom of denervation-induced skeletal muscle atrophy. In this paper, we developed a novel flexible tubular microelectrode integrated with fluidic drug delivery channel for dynamic tissue implant. First, the whole microelectrode was made of biocompatible polymers, which could avoid the drawbacks of the stiff microelectrodes that are easy to be broken and damage tissue. Moreover, the microelectrode sites were circumferentially distributed on the surface of polymer microtube in three dimensions, which would be beneficial to the spatial selectivity. Finally, the in vivo results confirmed that our implantable tubular microelectrodes were suitable for dynamic electrophysiological recording and simultaneous fluidic drug delivery, and the electrode performance was further enhanced by the conducting polymer modification.
Collapse
|
28
|
Implantable neurotechnologies: a review of micro- and nanoelectrodes for neural recording. Med Biol Eng Comput 2016; 54:23-44. [PMID: 26753777 DOI: 10.1007/s11517-015-1430-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 12/10/2015] [Indexed: 12/22/2022]
Abstract
Electrodes serve as the first critical interface to the biological organ system. In neuroprosthetic applications, for example, electrodes interface to the tissue for either signal recording or tissue stimulation. In this review, we consider electrodes for recording neural activity. Recording electrodes serve as wiretaps into the neural tissues, providing readouts of electrical activity. These signals give us valuable insights into the organization and functioning of the nervous system. The recording interfaces have also shown promise in aiding treatment of motor and sensory disabilities caused by neurological disorders. Recent advances in fabrication technology have generated wide interest in creating tiny, high-density electrode interfaces for neural tissues. An ideal electrode should be small enough and be able to achieve reliable and conformal integration with the structures of the nervous system. As a result, the existing electrode designs are being shrunk and packed to form small form factor interfaces to tissue. Here, an overview of the historic and state-of-the-art electrode technologies for recording neural activity is presented first with a focus on their development road map. The fact that the dimensions of recording electrode sites are being scaled down from micron to submicron scale to enable dense interfaces is appreciated. The current trends in recording electrode technologies are then reviewed. Current and future considerations in electrode design, including the use of inorganic nanostructures and biologically inspired or biocomapatible materials are discussed, along with an overview of the applications of flexible materials and transistor transduction schemes. Finally, we detail the major technical challenges facing chronic use of reliable recording electrode technology.
Collapse
|
29
|
Xie X, Rieth L, Caldwell R, Negi S, Bhandari R, Sharma R, Tathireddy P, Solzbacher F. Effect of bias voltage and temperature on lifetime of wireless neural interfaces with Al ₂O₃ and parylene bilayer encapsulation. Biomed Microdevices 2015; 17:1. [PMID: 25653054 DOI: 10.1007/s10544-014-9904-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The lifetime of neural interfaces is a critical challenge for chronic implantations, as therapeutic devices (e.g., neural prosthetics) will require decades of lifetime. We evaluated the lifetime of wireless Utah electrode array (UEA) based neural interfaces with a bilayer encapsulation scheme utilizing a combination of alumina deposited by Atomic Layer Deposition (ALD) and parylene C. Wireless integrated neural interfaces (INIs), equipped with recording version 9 (INI-R9) ASIC chips, were used to monitor the encapsulation performance through radio-frequency (RF) power and telemetry. The wireless devices were encapsulated with 52 nm of ALD Al2O3 and 6 μm of parylene C, and tested by soaking in phosphate buffered solution (PBS) at 57 °C for 4× accelerated lifetime testing. The INIs were also powered continuously through 2.765 MHz inductive power and forward telemetry link at unregulated 5 V. The bilayer encapsulated INIs were fully functional for ∼35 days (140 days at 37 °C equivalent) with consistent power-up frequencies (∼910 MHz), stable RF signal (∼-75 dBm), and 100 % command reception rate. This is ∼10 times of equivalent lifetime of INIs with parylene-only encapsulation (13 days) under same power condition at 37 °C. The bilayer coated INIs without continuous powering lasted over 1860 equivalent days (still working) at 37 °C. Those results suggest that bias stress is a significant factor to accelerate the failure of the encapsulated devices. The INIs failed completely within 5 days of the initial frequency shift of RF signal at 57 °C, which implied that the RF frequency shift is an early indicator of encapsulation/device failure.
Collapse
|
30
|
Gunasekera B, Saxena T, Bellamkonda R, Karumbaiah L. Intracortical recording interfaces: current challenges to chronic recording function. ACS Chem Neurosci 2015; 6:68-83. [PMID: 25587704 DOI: 10.1021/cn5002864] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Brain Computer Interfaces (BCIs) offer significant hope to tetraplegic and paraplegic individuals. This technology relies on extracting and translating motor intent to facilitate control of a computer cursor or to enable fine control of an external assistive device such as a prosthetic limb. Intracortical recording interfaces (IRIs) are critical components of BCIs and consist of arrays of penetrating electrodes that are implanted into the motor cortex of the brain. These multielectrode arrays (MEAs) are responsible for recording and conducting neural signals from local ensembles of neurons in the motor cortex with the high speed and spatiotemporal resolution that is required for exercising control of external assistive prostheses. Recent design and technological innovations in the field have led to significant improvements in BCI function. However, long-term (chronic) BCI function is severely compromised by short-term (acute) IRI recording failure. In this review, we will discuss the design and function of current IRIs. We will also review a host of recent advances that contribute significantly to our overall understanding of the cellular and molecular events that lead to acute recording failure of these invasive implants. We will also present recent improvements to IRI design and provide insights into the futuristic design of more chronically functional IRIs.
Collapse
Affiliation(s)
- Bhagya Gunasekera
- Regenerative
Bioscience Center, ADS Complex, The University of Georgia, Athens, Georgia 30602-2771, United States
| | - Tarun Saxena
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0535, United States
| | - Ravi Bellamkonda
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0535, United States
| | - Lohitash Karumbaiah
- Regenerative
Bioscience Center, ADS Complex, The University of Georgia, Athens, Georgia 30602-2771, United States
| |
Collapse
|
31
|
Jorfi M, Skousen JL, Weder C, Capadona JR. Progress towards biocompatible intracortical microelectrodes for neural interfacing applications. J Neural Eng 2014; 12:011001. [PMID: 25460808 DOI: 10.1088/1741-2560/12/1/011001] [Citation(s) in RCA: 221] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To ensure long-term consistent neural recordings, next-generation intracortical microelectrodes are being developed with an increased emphasis on reducing the neuro-inflammatory response. The increased emphasis stems from the improved understanding of the multifaceted role that inflammation may play in disrupting both biologic and abiologic components of the overall neural interface circuit. To combat neuro-inflammation and improve recording quality, the field is actively progressing from traditional inorganic materials towards approaches that either minimizes the microelectrode footprint or that incorporate compliant materials, bioactive molecules, conducting polymers or nanomaterials. However, the immune-privileged cortical tissue introduces an added complexity compared to other biomedical applications that remains to be fully understood. This review provides a comprehensive reflection on the current understanding of the key failure modes that may impact intracortical microelectrode performance. In addition, a detailed overview of the current status of various materials-based approaches that have gained interest for neural interfacing applications is presented, and key challenges that remain to be overcome are discussed. Finally, we present our vision on the future directions of materials-based treatments to improve intracortical microelectrodes for neural interfacing.
Collapse
Affiliation(s)
- Mehdi Jorfi
- Adolphe Merkle Institute, University of Fribourg, Rte de l'Ancienne Papeterie, CH-1723 Marly, Switzerland
| | | | | | | |
Collapse
|
32
|
|
33
|
Kim J, Lee M, Rhim JS, Wang P, Lu N, Kim DH. Next-generation flexible neural and cardiac electrode arrays. Biomed Eng Lett 2014. [DOI: 10.1007/s13534-014-0132-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
|
34
|
Fattahi P, Yang G, Kim G, Abidian MR. A review of organic and inorganic biomaterials for neural interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:1846-85. [PMID: 24677434 PMCID: PMC4373558 DOI: 10.1002/adma.201304496] [Citation(s) in RCA: 300] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/08/2013] [Indexed: 05/18/2023]
Abstract
Recent advances in nanotechnology have generated wide interest in applying nanomaterials for neural prostheses. An ideal neural interface should create seamless integration into the nervous system and performs reliably for long periods of time. As a result, many nanoscale materials not originally developed for neural interfaces become attractive candidates to detect neural signals and stimulate neurons. In this comprehensive review, an overview of state-of-the-art microelectrode technologies provided fi rst, with focus on the material properties of these microdevices. The advancements in electro active nanomaterials are then reviewed, including conducting polymers, carbon nanotubes, graphene, silicon nanowires, and hybrid organic-inorganic nanomaterials, for neural recording, stimulation, and growth. Finally, technical and scientific challenges are discussed regarding biocompatibility, mechanical mismatch, and electrical properties faced by these nanomaterials for the development of long-lasting functional neural interfaces.
Collapse
Affiliation(s)
- Pouria Fattahi
- Biomedical Engineering Department and Chemical Engineering Departments, Pennsylvania State University, University Park, PA, 16802, USA
| | - Guang Yang
- Biomedical Engineering Department, Pennsylvania State University, University Park, PA, 16802, USA
| | - Gloria Kim
- Biomedical Engineering Department, Pennsylvania State University, University Park, PA, 16802, USA
| | - Mohammad Reza Abidian
- Biomedical Engineering Department, Materials Science & Engineering Department, Chemical Engineering Department, Materials Research Institute, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, 16802, USA
| |
Collapse
|
35
|
Xie X, Rieth L, Williams L, Negi S, Bhandari R, Caldwell R, Sharma R, Tathireddy P, Solzbacher F. Long-term reliability of Al2O3 and Parylene C bilayer encapsulated Utah electrode array based neural interfaces for chronic implantation. J Neural Eng 2014; 11:026016. [PMID: 24658358 DOI: 10.1088/1741-2560/11/2/026016] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE We focus on improving the long-term stability and functionality of neural interfaces for chronic implantation by using bilayer encapsulation. APPROACH We evaluated the long-term reliability of Utah electrode array (UEA) based neural interfaces encapsulated by 52 nm of atomic layer deposited Al2O3 and 6 µm of Parylene C bilayer, and compared these to devices with the baseline Parylene-only encapsulation. Three variants of arrays including wired, wireless, and active UEAs were used to evaluate this bilayer encapsulation scheme, and were immersed in phosphate buffered saline (PBS) at 57 °C for accelerated lifetime testing. MAIN RESULTS The median tip impedance of the bilayer encapsulated wired UEAs increased from 60 to 160 kΩ during the 960 days of equivalent soak testing at 37 °C, the opposite trend to that typically observed for Parylene encapsulated devices. The loss of the iridium oxide tip metallization and etching of the silicon tip in PBS solution contributed to the increase of impedance. The lifetime of fully integrated wireless UEAs was also tested using accelerated lifetime measurement techniques. The bilayer coated devices had stable power-up frequencies at ∼910 MHz and constant radio-frequency signal strength of -50 dBm during up to 1044 days (still under testing) of equivalent soaking time at 37 °C. This is a significant improvement over the lifetime of ∼100 days achieved with Parylene-only encapsulation at 37 °C. The preliminary samples of bilayer coated active UEAs with a flip-chip bonded ASIC chip had a steady current draw of ∼3 mA during 228 days of soak testing at 37 °C. An increase in the current draw has been consistently correlated to device failures, so is a sensitive metric for their lifetime. SIGNIFICANCE The trends of increasing electrode impedance of wired devices and performance stability of wireless and active devices support the significantly greater encapsulation performance of this bilayer encapsulation compared with Parylene-only encapsulation. The bilayer encapsulation should significantly improve the in vivo lifetime of neural interfaces for chronic implantation.
Collapse
Affiliation(s)
- Xianzong Xie
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Xie X, Rieth L, Negi S, Bhandari R, Caldwell R, Sharma R, Tathireddy P, Solzbacher F. SELF ALIGNED TIP DEINSULATION OF ATOMIC LAYER DEPOSITED AL 2O 3 AND PARYLENE C COATED UTAH ELECTRODE ARRAY BASED NEURAL INTERFACES. JOURNAL OF MICROMECHANICS AND MICROENGINEERING : STRUCTURES, DEVICES, AND SYSTEMS 2014; 24:035003. [PMID: 24771981 PMCID: PMC3994722 DOI: 10.1088/0960-1317/24/3/035003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The recently developed alumina and Parylene C bi-layer encapsulation improved the lifetime of neural interfaces. Tip deinsulation of Utah electrode array based neural interfaces is challenging due to the complex 3D geometries and high aspect ratios of the devices. A three-step self-aligned process was developed for tip deinsulation of bilayer encapsulated arrays. The deinsulation process utilizes laser ablation to remove Parylene C, O2 reactive ion etching to remove carbon and Parylene residues, and buffered oxide etch to remove alumina deposited by atomic layer deposition, and expose the IrOx tip metallization. The deinsulated iridium oxide area was characterized by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy to determine the morphology, surface morphology, composition, and electrical properties of the deposited layers and deinsulated tips. The alumina layer was found to prevent the formation of micro cracks on iridium oxide during the laser ablation process, which has been previously reported as a challenge for laser deinsulation of Parylene films. The charge injection capacity, charge storage capacity, and impedance of deinsulated iridium oxide were characterized to determine the deinsulation efficacy compared to Parylene-only insulation. Deinsulated iridium oxide with bilayer encapsulation had higher charge injection capacity (240 vs 320 nC) and similar electrochemical impedance (2.5 vs 2.5 kΩ) compared to deinsulated iridium oxide with only Parylene coating for an area of 2 × 10-4 cm2. Tip impedances were in the ranges of 20 to 50 kΩ, with median of 32 KΩ and standard deviation of 30 kΩ, showing the effectiveness of the self-aligned deinsulation process for alumina and Parylene C bi-layer encapsulation. The relatively uniform tip impedance values demonstrated the consistency of tip exposures.
Collapse
Affiliation(s)
- Xianzong Xie
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112 USA
| | - Loren Rieth
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112 USA
| | - Sandeep Negi
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112 USA
| | | | - Ryan Caldwell
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112 USA
| | - Rohit Sharma
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112 USA
| | - Prashant Tathireddy
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112 USA
| | - Florian Solzbacher
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112 USA ; Department of Bioengineering, University of Utah, Salt Lake City, UT 84112 USA
| |
Collapse
|
37
|
Graphene oxide doped conducting polymer nanocomposite film for electrode-tissue interface. Biomaterials 2013; 35:2120-9. [PMID: 24333027 DOI: 10.1016/j.biomaterials.2013.11.058] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 11/21/2013] [Indexed: 01/09/2023]
Abstract
One of the most significant components for implantable bioelectronic devices is the interface between the microelectrodes and the tissue or cells for disease diagnosis or treatment. To make the devices work efficiently and safely in vivo, the electrode-tissue interface should not only be confined in micro scale, but also possesses excellent electrochemical characteristic, stability and biocompatibility. Considering the enhancement of many composite materials by combining graphene oxide (GO) for its multiple advantages, we dope graphene oxide into poly(3,4-ethylenedioxythiophene) (PEDOT) forming a composite film by electrochemical deposition for electrode site modification. As a consequence, not only the enlargement of efficient surface area, but also the development of impedance, charge storage capacity and charge injection limit contribute to the excellent electrochemical performance. Furthermore, the stability and biocompatibility are confirmed by numerously repeated usage test and cell proliferation and attachment examination, respectively. As electrode-tissue interface, this biomaterial opens a new gate for tissue engineering and implantable electrophysiological devices.
Collapse
|
38
|
Pang C, Lee C, Suh KY. Recent advances in flexible sensors for wearable and implantable devices. J Appl Polym Sci 2013. [DOI: 10.1002/app.39461] [Citation(s) in RCA: 342] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
39
|
Gill EC, Antalek J, Kimock FM, Nasiatka PJ, McIntosh BP, Tanguay AR, Weiland JD. High-Density Feedthrough Technology for Hermetic Biomedical Micropackaging. ACTA ACUST UNITED AC 2013. [DOI: 10.1557/opl.2013.735] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTImplantable electronic biomedical devices are used clinically to diagnose and treat an increasing number of medical conditions. Such devices typically employ hermetic packages that often incorporate electrical feedthroughs made with conventional ceramic-to-metal bonding technologies. This sealing technology is well established and provides robust hermetic seals, but is limited in both the number and spacing of electrical leads. Emerging devices for interfacing with the human nervous system, however, will require a large number of external electrical leads implemented in a miniaturized packaging configuration. Commercially available feedthrough technologies are currently incapable of providing external electrical contacts with spacings as small as 200 to 400 microns, and thus are neither compatible with integrated circuit I/O (input/output) pad spacings nor with miniature implantable packages. We report the development of a hermetic high-density feedthrough (HDF) technology that allows for conductive path densities as high as 1,000 per cm2, and that is capable of supporting neural interface devices. The fabrication process utilizes multilayer high temperature co-fired ceramic (HTCC) technology in conjunction with platinum leads. Before co-firing, green alumina substrates are interleaved with linear, parallel Pt trace arrays in either wire or thin foils to form the electrical feedthroughs. Layered stacks of spatially isolated traces are first compacted into a composite, and then fired to achieve densification. After firing, the densified multilayered composite compacts are sliced perpendicular to the Pt traces and lapped to produce multiple feedthrough arrays with a high density of leads (conductors). Both hermeticity and biocompatibility of such implantable feedthroughs are important, as both moisture and positive mobile ion contamination from the saline environment of the human body can lead to compromised performance or catastrophic failure. HDFs fabricated using this process with 100 conductors and lead-to-lead spacings as low as 400 microns have been helium leak tested repeatedly and found to exceed industry-accepted standards with helium leak rates in the range of 10–11 mbar-l/s. The spacing of the current prototype matches industry standard neural interface technology, and can be scaled to higher densities with lead-to-lead spacings as small as 200 microns. The reported HDF process has several distinct advantages over prior approaches, including the provision of a large number of conductive feedthrough leads suitable for flip-chip bonding with sub-mm lead-to-lead spacings (pitch), and the incorporation of materials (alumina and platinum) that are already used in medical implants. The implementation of such an HDF technology allows for significant package miniaturization, allowing greater flexibility in surgical placement as well as less invasive procedures for implantable electronic biomedical devices.
Collapse
|
40
|
Xie X, Rieth L, Caldwell R, Diwekar M, Tathireddy P, Sharma R, Solzbacher F. Long-term bilayer encapsulation performance of atomic layer deposited Al₂O₃ and Parylene C for biomedical implantable devices. IEEE Trans Biomed Eng 2013; 60:2943-51. [PMID: 23751949 DOI: 10.1109/tbme.2013.2266542] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We present an encapsulation scheme that combines atomic layer deposited (ALD) Al₂O₃ and Parylene C for the encapsulation of implantable devices. The encapsulation performances of combining alumina and Parylene C was compared to individual layers of Parylene C or alumina and the bilayer coating had superior encapsulation properties. The alumina-Parylene coated interdigitated electrodes (IDEs) soaked in PBS for up to nine months at temperatures from 37 to 80 °C for accelerated lifetime testing. For 52-nm alumina and 6-μm Parylene C, leakage current was ∼20 pA at 5 VDC, and the impedance was about 3.5 MΩ at 1 kHz with a phase near -87° from electrochemical impedance spectroscopy for samples soaked at 67 °C for equivalent lifetime of 72 months at 37 °C. The change of impedance during the whole soaking period (up to 70 months of equivalent soaking time at 37 °C) over 1 to 10⁶ Hz was within 5%. The stability of impedance indicated almost no degradation of the encapsulation. Bias voltage effect was studied by continuously applying 5 VDC, and it reduced the lifetime of Parylene coating by ∼75% while it showed no measurable effect on the bilayer coating. Lifetime of encapsulation of IDEs with topography generated by attaching a coil and surface mount device (SMD) capacitor was about half of that of planer IDEs. The stable long-term insulation impedance, low leakage current, and better lifetime under bias voltage and topography made this double-layer encapsulation very promising for chronic implantable devices.
Collapse
|
41
|
Robinson JT, Jorgolli M, Park H. Nanowire electrodes for high-density stimulation and measurement of neural circuits. Front Neural Circuits 2013; 7:38. [PMID: 23486552 PMCID: PMC3594763 DOI: 10.3389/fncir.2013.00038] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 02/24/2013] [Indexed: 11/13/2022] Open
Abstract
Brain-machine interfaces (BMIs) that can precisely monitor and control neural activity will likely require new hardware with improved resolution and specificity. New nanofabricated electrodes with feature sizes and densities comparable to neural circuits may lead to such improvements. In this perspective, we review the recent development of vertical nanowire (NW) electrodes that could provide highly parallel single-cell recording and stimulation for future BMIs. We compare the advantages of these devices and discuss some of the technical challenges that must be overcome for this technology to become a platform for next-generation closed-loop BMIs.
Collapse
Affiliation(s)
- Jacob T Robinson
- Departments of Electrical and Computer Engineering and Bioengineering, Rice University Houston, TX, USA
| | | | | |
Collapse
|
42
|
Three-Dimensional Flexible Polyimide Based Probe Array with Stiffness Improvement by Using Biodegradable Polymer. ACTA ACUST UNITED AC 2013. [DOI: 10.4028/www.scientific.net/amr.651.517] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This work presents a three-dimensional flexible polyimide (PI) probe array with biodegradable polymer that offers desirable insertion capability. In order to avoid the recording sites position shifts slightly and damage neuron cells when the body moves, the flexible neural probes are more preferable than traditional Si-based neural probes. A sufficient buckling strength of flexible probe is critical for inserting flexible probe into the brain. Here, we used a biodegradable polymer, polyethylene glycol (PEG), to improve the mechanical stiffness of flexible probe. PEG, which is solid state at room temperature and dissolves when immersing in water, was coated onto the flexible probe and the mechanical stiffness of the flexible probe was increased before insertion into the biological tissue. The buckling strength of different probes was simulated using finite element analysis and measured by compression tester. The coated PEG flexible probe maintains sufficient stiffness to facilitate tissue penetration with solid PEG elastic modulus of 660±19 MPa but loses its strength within 25 minutes once immersed in saline. A microassembly method of three-dimensional flexible probe array was also proposed to integrate the flexible probe and their interconnections. In vitro test, the coated PEG flexible probe regained their original impedance of 12.8 kΩ at 1 kHz within 30 minutes of immersing in saline via water absorption and polymer’s biodegradable response.
Collapse
|
43
|
Lind G, Gällentoft L, Danielsen N, Schouenborg J, Pettersson LME. Multiple implants do not aggravate the tissue reaction in rat brain. PLoS One 2012; 7:e47509. [PMID: 23091629 PMCID: PMC3472973 DOI: 10.1371/journal.pone.0047509] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 09/14/2012] [Indexed: 11/18/2022] Open
Abstract
Chronically implanted microelectrodes are an invaluable tool for neuroscientific research, allowing long term recordings in awake and behaving animals. It is known that all such electrodes will evoke a tissue reaction affected by its’ size, shape, surface structure, fixation mode and implantation method. However, the possible correlation between tissue reactions and the number of implanted electrodes is not clear. We implanted multiple wire bundles into the brain of rats and studied the correlation between the astrocytic and microglial reaction and the positioning of the electrode in relation to surrounding electrodes. We found that an electrode implanted in the middle of a row of implants is surrounded by a significantly smaller astrocytic scar than single ones. This possible interaction was only seen between implants within the same hemisphere, no interaction with the contralateral hemisphere was found. More importantly, we found no aggravation of tissue reactions as a result of a larger number of implants. These results highlight the possibility of implanting multiple electrodes without aggravating the glial scar surrounding each implant.
Collapse
Affiliation(s)
- Gustav Lind
- Department of Experimental Medical Sciences, Neuronano Research Center, Medical Faculty, Lund University, Lund, Sweden.
| | | | | | | | | |
Collapse
|
44
|
Xie X, Rieth L, Merugu S, Tathireddy P, Solzbacher F. Plasma-assisted atomic layer deposition of Al(2)O(3) and parylene C bi-layer encapsulation for chronic implantable electronics. APPLIED PHYSICS LETTERS 2012; 101:93702. [PMID: 23024377 PMCID: PMC3443113 DOI: 10.1063/1.4748322] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 08/14/2012] [Indexed: 05/19/2023]
Abstract
Encapsulation of biomedical implants with complex three dimensional geometries is one of the greatest challenges achieving long-term functionality and stability. This report presents an encapsulation scheme that combines Al(2)O(3) by atomic layer deposition with parylene C for implantable electronic systems. The Al(2)O(3)-parylene C bi-layer was used to encapsulate interdigitated electrodes, which were tested invitro by soak testing in phosphate buffered saline solution at body temperature (37 °C) and elevated temperatures (57 °C and 67 °C) for accelerated lifetime testing up to 5 months. Leakage current and electrochemical impedance spectroscopy were measured for evaluating the integrity and insulation performance of the coating. Leakage current was stably about 15 pA at 5 V dc, and impedance was constantly about 3.5 MΩ at 1 kHz by using electrochemical impedance spectroscopy for samples under 67 °C about 5 months (approximately equivalent to 40 months at 37 °C). Alumina and parylene coating lasted at least 3 times longer than parylene coated samples tested at 80 °C. The excellent insulation performance of the encapsulation shows its potential usefulness for chronic implants.
Collapse
Affiliation(s)
- Xianzong Xie
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112, USA
| | | | | | | | | |
Collapse
|
45
|
Kim DH, Ghaffari R, Lu N, Rogers JA. Flexible and stretchable electronics for biointegrated devices. Annu Rev Biomed Eng 2012; 14:113-28. [PMID: 22524391 DOI: 10.1146/annurev-bioeng-071811-150018] [Citation(s) in RCA: 308] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Advances in materials, mechanics, and manufacturing now allow construction of high-quality electronics and optoelectronics in forms that can readily integrate with the soft, curvilinear, and time-dynamic surfaces of the human body. The resulting capabilities create new opportunities for studying disease states, improving surgical procedures, monitoring health/wellness, establishing human-machine interfaces, and performing other functions. This review summarizes these technologies and illustrates their use in forms integrated with the brain, the heart, and the skin.
Collapse
Affiliation(s)
- Dae-Hyeong Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 151-744, Korea
| | | | | | | |
Collapse
|
46
|
Chang SI, AlAshmouny K, Yoon E. A 1.5V 120nW CMOS programmable monolithic reference generator for wireless implantable system. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:2981-4. [PMID: 22254967 DOI: 10.1109/iembs.2011.6090818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We implement and characterize a 1.5 V 120 nW CMOS programmable monolithic reference generator for wireless implantable system. The proposed generator is optimized to be tolerable for power supply variation in a small area with programmability to generate various reference voltages and currents. The measured power line sensitivity are 0.02 / 1.1%/V for voltage and current reference, respectively. This reference generator can operate for input voltage ranging from 1.5 V to 3.5 V and implemented in an area of 0.011 mm(2), which is the smallest monolithic reference generator in 0.25 μm technology to the best of our knowledge. The output can vary from 20 nA to 33 nA for current reference and from 0.71 V to 1.03 V for voltage reference.
Collapse
Affiliation(s)
- Sun-Il Chang
- Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor, MI 48109, USA.
| | | | | |
Collapse
|
47
|
Schwerdt HN, Xu W, Shekhar S, Abbaspour-Tamijani A, Towe BC, Miranda FA, Chae J. A Fully-Passive Wireless Microsystem for Recording of Neuropotentials using RF Backscattering Methods. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS : A JOINT IEEE AND ASME PUBLICATION ON MICROSTRUCTURES, MICROACTUATORS, MICROSENSORS, AND MICROSYSTEMS 2011; 20:1119-1130. [PMID: 22267898 PMCID: PMC3259707 DOI: 10.1109/jmems.2011.2162487] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The ability to safely monitor neuropotentials is essential in establishing methods to study the brain. Current research focuses on the wireless telemetry aspect of implantable sensors in order to make these devices ubiquitous and safe. Chronic implants necessitate superior reliability and durability of the integrated electronics. The power consumption of implanted electronics must also be limited to within several milliwatts to microwatts to minimize heat trauma in the human body. In order to address these severe requirements, we developed an entirely passive and wireless microsystem for recording neuropotentials. An external interrogator supplies a fundamental microwave carrier to the microsystem. The microsystem comprises varactors that perform nonlinear mixing of neuropotential and fundamental carrier signals. The varactors generate third-order mixing products that are wirelessly backscattered to the external interrogator where the original neuropotential signals are recovered. Performance of the neuro-recording microsystem was demonstrated by wireless recording of emulated and in vivo neuropotentials. The obtained results were wireless recovery of neuropotentials as low as approximately 500 microvolts peak-to-peak (μV(pp)) with a bandwidth of 10 Hz to 3 kHz (for emulated signals) and with 128 epoch signal averaging of repetitive signals (for in vivo signals).
Collapse
Affiliation(s)
- Helen N Schwerdt
- School of Electrical, Computer, and Energy Engineering at Arizona State University, Tempe, AZ 85287 USA
| | | | | | | | | | | | | |
Collapse
|
48
|
Abstract
A new parylene-based microfabrication process is presented for neural recording and drug delivery applications. We introduce a large design space for electrode placement and structural flexibility with a six mask process. By using chemical mechanical polishing, electrode sites may be created top-side, back-side, or on the edge of the device having three exposed sides. Added surface area was achieved on the exposed edge through electroplating. Poly(3,4-ethylenedioxythiophene) (PEDOT) modified edge electrodes having an 85-μm(2) footprint resulted in an impedance of 200 kΩ at 1 kHz. Edge electrodes were able to successfully record single unit activity in acute animal studies. A finite element model of planar and edge electrodes relative to neuron position reveals that edge electrodes should be beneficial for increasing the volume of tissue being sampled in recording applications.
Collapse
|
49
|
Seung Woo Lee, Kyou Sik Min, Joonsoo Jeong, Junghoon Kim, Sung June Kim. Monolithic Encapsulation of Implantable Neuroprosthetic Devices Using Liquid Crystal Polymers. IEEE Trans Biomed Eng 2011. [DOI: 10.1109/tbme.2011.2136341] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
50
|
Sharma A, Rieth L, Tathireddy P, Harrison R, Oppermann H, Klein M, Töpper M, Jung E, Normann R, Clark G, Solzbacher F. Long term in vitro functional stability and recording longevity of fully integrated wireless neural interfaces based on the Utah Slant Electrode Array. J Neural Eng 2011; 8:045004. [PMID: 21775785 DOI: 10.1088/1741-2560/8/4/045004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We evaluate the encapsulation and packaging reliability of a fully integrated wireless neural interface based on a Utah Slant Electrode Array/integrated neural interface-recording version 5 (USEA/INI-R5) system by monitoring the long term in vitro functional stability and recording longevity. The INI encapsulated with 6 µm Parylene-C was immersed in phosphate buffered saline (PBS) for a period of over 276 days (with the monitoring of the functional device still ongoing). The full functionality (wireless radio-frequency power, command and signal transmission) and the ability of the electrodes to record artificial neural signals even after 276 days of PBS soaking with little change (within 14%) in signal/noise amplitude constitute a major milestone in long term stability and allow us to study and evaluate the encapsulation reliability, functional stability and its potential usefulness for a wireless neural interface for future chronic implants.
Collapse
Affiliation(s)
- Asha Sharma
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|