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Yan D, Ruiz JRL, Hsieh ML, Jeong D, Vöröslakos M, Lanzio V, Warner EV, Ko E, Tian Y, Patel PR, ElBidweihy H, Smith CS, Lee JH, Cheon J, Buzsáki G, Yoon E. Self-Assembled Origami Neural Probes for Scalable, Multifunctional, Three-Dimensional Neural Interface. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.25.591141. [PMID: 38712092 PMCID: PMC11071508 DOI: 10.1101/2024.04.25.591141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Flexible intracortical neural probes have drawn attention for their enhanced longevity in high-resolution neural recordings due to reduced tissue reaction. However, the conventional monolithic fabrication approach has met significant challenges in: (i) scaling the number of recording sites for electrophysiology; (ii) integrating of other physiological sensing and modulation; and (iii) configuring into three-dimensional (3D) shapes for multi-sided electrode arrays. We report an innovative self-assembly technology that allows for implementing flexible origami neural probes as an effective alternative to overcome these challenges. By using magnetic-field-assisted hybrid self-assembly, multiple probes with various modalities can be stacked on top of each other with precise alignment. Using this approach, we demonstrated a multifunctional device with scalable high-density recording sites, dopamine sensors and a temperature sensor integrated on a single flexible probe. Simultaneous large-scale, high-spatial-resolution electrophysiology was demonstrated along with local temperature sensing and dopamine concentration monitoring. A high-density 3D origami probe was assembled by wrapping planar probes around a thin fiber in a diameter of 80∼105 μm using optimal foldable design and capillary force. Directional optogenetic modulation could be achieved with illumination from the neuron-sized micro-LEDs (μLEDs) integrated on the surface of 3D origami probes. We could identify angular heterogeneous single-unit signals and neural connectivity 360° surrounding the probe. The probe longevity was validated by chronic recordings of 64-channel stacked probes in behaving mice for up to 140 days. With the modular, customizable assembly technologies presented, we demonstrated a novel and highly flexible solution to accommodate multifunctional integration, channel scaling, and 3D array configuration.
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Ahn SH, Koh CS, Park M, Jun SB, Chang JW, Kim SJ, Jung HH, Jeong J. Liquid Crystal Polymer-Based Miniaturized Fully Implantable Deep Brain Stimulator. Polymers (Basel) 2023; 15:4439. [PMID: 38006163 PMCID: PMC10675735 DOI: 10.3390/polym15224439] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/22/2023] [Accepted: 10/27/2023] [Indexed: 11/26/2023] Open
Abstract
A significant challenge in improving the deep brain stimulation (DBS) system is the miniaturization of the device, aiming to integrate both the stimulator and the electrode into a compact unit with a wireless charging capability to reduce invasiveness. We present a miniaturized, fully implantable, and battery-free DBS system designed for rats, using a liquid crystal polymer (LCP), a biocompatible and long-term reliable material. The system integrates the simulator circuit, the receiver coil, and a 20 mm long depth-type microelectrode array in a dome-shaped LCP package that is 13 mm in diameter and 5 mm in height. Wireless powering and control via an inductive link enable device miniaturization, allowing for full implantation and, thus, the free behavior of untethered animals. The eight-channel stimulation electrode array was microfabricated on an LCP substrate to form a multilayered system substrate, which was monolithically encapsulated by a domed LCP lid using a specialized spot-welding process. The device functionality was validated via an in vivo animal experiment using a neuropathic pain model in rats. This experiment demonstrated an increase in the mechanical withdrawal threshold of the rats with microelectrical stimulation delivered using the fully implanted device, highlighting the effectiveness of the system.
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Affiliation(s)
- Seung-Hee Ahn
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Chin Su Koh
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Minkyung Park
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Sang Beom Jun
- Department of Electronic and Electrical Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Jin Woo Chang
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Sung June Kim
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyun Ho Jung
- Department of Neurosurgery, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Joonsoo Jeong
- School of Biomedical Convergence Engineering, Pusan National University, Yangsan 50612, Republic of Korea
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Zhang Z, Yang X, Zhao Y, Ye F, Shang L. Liquid Crystal Materials for Biomedical Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2300220. [PMID: 37235719 DOI: 10.1002/adma.202300220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 04/04/2023] [Indexed: 05/28/2023]
Abstract
Liquid crystal is a state of matter being intermediate between solid and liquid. Liquid crystal materials exhibit both orientational order and fluidity. While liquid crystals have long been highly recognized in the display industry, in recent decades, liquid crystals provide new opportunities into the cross-field of material science and biomedicine due to their biocompatibility, multifunctionality, and responsiveness. In this review, the latest achievements of liquid crystal materials applied in biomedical fields are summarized. The start is made by introducing the basic concepts of liquid crystals, and then shifting to the components of liquid crystals as well as functional materials derived therefrom. After that, the ongoing and foreseeable applications of liquid crystal materials in the biomedical field with emphasis put on several cutting-edge aspects, including drug delivery, bioimaging, tissue engineering, implantable devices, biosensing, and wearable devices are discussed. It is hoped that this review will stimulate ingenious ideas for the future generation of liquid crystal-based drug development, artificial implants, disease diagnosis, health status monitoring, and beyond.
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Affiliation(s)
- Zhuohao Zhang
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, and the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Xinyuan Yang
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, and the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Yuanjin Zhao
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, and the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering Southeast University, Nanjing, 210096, China
| | - Fangfu Ye
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang, 325001, China
| | - Luoran Shang
- Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, and the Shanghai Key Laboratory of Medical Epigenetics, the International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering Southeast University, Nanjing, 210096, China
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Guljakow J, Lang W. Failure Reason of PI Test Samples of Neural Implants. SENSORS (BASEL, SWITZERLAND) 2023; 23:1340. [PMID: 36772377 PMCID: PMC9919689 DOI: 10.3390/s23031340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Samples that were meant to simulate the behavior of neural implants were put into Ringer's solution, and the occurring damage was assessed. The samples consist of an interdigitated gold-structure and two contact pads embedded between two Polyimide layers, resulting in free-floating structures. The two parts of the interdigitated structure have no electric contacts and are submerged in the solution during the experiment. The samples were held at temperatures of 37 and 57 ∘C in order to undergo an accelerated lifetime test and to compare the results. During the course of the experiment, a voltage was applied and measured over a resistance of 1 kOhm over time. Arduinos were used as measuring devices. As the intact samples are insulating, a sudden rise in voltage indicates a sample failure due to liquid leaking in between the two polyimide layers. Once a short-circuit occurred and a sample broke down, the samples were taken out of the vial and examined under a microscope. In virtually all cases, delamination was observable, with variation in the extent of the delaminated area. A comparison between measured voltages after failure and damage did not show a correlation between voltage and area affected by delamination. However, at a temperature of 37 ∘C, voltage remained constant most of the time after delamination, and a pin-hole lead to a lower measured voltage and strong fluctuations. Visually, no difference in damage between the 37 and the 57 ∘C samples was observed, although fluctuations of measured voltage occurred in numerous samples at a higher temperature. This difference hints at differences in the reasons for failure and thus limited applicability of accelerated lifetime tests.
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Choi GJ, Yoo HJ, Cho Y, Shim S, Yun S, Sung J, Lim Y, Jun SB, Kim SJ. Development of a miniaturized, reconnectable, and implantable multichannel connector. J Neural Eng 2022; 19. [PMID: 36228595 DOI: 10.1088/1741-2552/ac99ff] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/13/2022] [Indexed: 12/24/2022]
Abstract
Objective. Connectors for implantable neural prosthetic systems provide several advantages such as simplification of surgery, safe replacement of implanted devices, and modular design of the implant systems. With the rapid advancement of technologies for neural implants, miniaturized multichannel implantable connectors are also required. In this study, we propose a reconnectable and area-efficient multichannel implantable connector.Approach. A female-to-female adapter was fabricated using the thermal-press bonding of micropatterned liquid crystal polymer films. A bump inside the adapter enabled a reliable electrical connection by increasing the contact pressure between the contact pads of the adapter and the inserted cable. After connection, the adapter is enclosed in a metal case sealed with silicone elastomer packing. With different sizes of the packings, leakage current tests were performed under accelerated conditions to determine the optimal design for long-term reliability. Repeated connection tests were performed to verify the durability and reconnectability of the fabricated connector. The connector was implanted in rats, and the leakage currents were monitored to evaluate the stability of the connectorin vivo. Main results. The fabricated four- and eight-channel implantable connectors, assembled with the metal cases, had a diameter and length of 6 and 17 mm, respectively. Further, the contact resistances of the four- and eight-channel connectors were 53.2 and 75.2 mΩ, respectively. The electrical contact remained stable during repeated connection tests (50 times). The fabricated connectors with packings having 125%, 137%, and 150% volume ratios to the internal space of the metal case failed after 14, 88, and 14 d, respectively, in a 75 °C saline environment. In animal tests with rats, the connector maintained low leakage current levels for up to 92 d.Significance. An implantable and reconnectable multichannel connector was developed and evaluated. The feasibility of the proposed connector was evaluated in terms of electrical and mechanical characteristics as well as sealing performance. The proposed connector is expected to have potential applications in implantable neural prosthetic systems.
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Affiliation(s)
- Gwang Jin Choi
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, Republic of Korea
| | - Hyun Ji Yoo
- Department of Electronic and Electrical Engineering, Ewha Womans University, Seoul, Republic of Korea
| | - YoonKyung Cho
- Department of Electronic and Electrical Engineering, Ewha Womans University, Seoul, Republic of Korea
| | - Shinyong Shim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, Republic of Korea
| | - Seunghyeon Yun
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, Republic of Korea
| | - Jaehoon Sung
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, United States of America (On a leave of absence)
| | - Yoonseob Lim
- Center for Intelligent and Interactive Robotics, Korea Institute of Science and Technology, Seoul, Republic of Korea.,Department of HY-KIST Bio-convergence, Hanyang University, Seoul, Republic of Korea
| | - Sang Beom Jun
- Department of Electronic and Electrical Engineering, Ewha Womans University, Seoul, Republic of Korea.,Graduate Program in Smart Factory, Ewha Womans University, Seoul, Republic of Korea.,Division of Brain and Cognitive Sciences, Ewha Womans University, Seoul, Republic of Korea
| | - Sung June Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, Republic of Korea
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Rakkiyannan J, Jakkamputi L, Thangamuthu M, Patange AD, Gnanasekaran S. Development of Online Tool Wear-Out Detection System Using Silver-Polyester Thick Film Sensor for Low-Duty Cycle Machining Operations. SENSORS (BASEL, SWITZERLAND) 2022; 22:8200. [PMID: 36365899 PMCID: PMC9658968 DOI: 10.3390/s22218200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/16/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
This paper deals with the design and development of a silver-polyester thick film sensor and associated system for the wear-out detection of single-point cutting tools for low-duty cycle machining operations. Conventional means of wear-out detection use dynamometers, accelerometers, microphones, acoustic emission sensors, thermal infrared cameras, and machine vision systems that detect tool wear during the process. Direct measurements with optical instruments are accurate but affect the machining process. In this study, the use of a thick film sensor to detect wear-out for aa real-time low-duty machining operation was proposed to eliminate the limitations of the current methods. The proposed sensor monitors the tool condition accurately as the wear acts directly on the sensor, which makes the system simple and more reliable. The effect of tool temperature on the sensor during the machining operation was also studied to determine the displacement/deformation of tracing and the polymer substrate at different service temperatures. The proposed tool wear detection system with the silver-polyester thick film sensor mounted directly on the cutting tool tip proved to be highly capable of detecting the tool wear with good reliability.
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Affiliation(s)
- Jegadeeshwaran Rakkiyannan
- Center for Automation, School of Mechanical Engineering, Vellore Institute of Technology, Chennai 600127, India
| | | | - Mohanraj Thangamuthu
- Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Coimbatore 641112, India
| | - Abhishek D. Patange
- Department of Mechanical Engineering, College of Engineering Pune, Pune 411005, India
| | - Sakthivel Gnanasekaran
- Center for Automation, School of Mechanical Engineering, Vellore Institute of Technology, Chennai 600127, India
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Bod RB, Rokai J, Meszéna D, Fiáth R, Ulbert I, Márton G. From End to End: Gaining, Sorting, and Employing High-Density Neural Single Unit Recordings. Front Neuroinform 2022; 16:851024. [PMID: 35769832 PMCID: PMC9236662 DOI: 10.3389/fninf.2022.851024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 05/06/2022] [Indexed: 11/15/2022] Open
Abstract
The meaning behind neural single unit activity has constantly been a challenge, so it will persist in the foreseeable future. As one of the most sourced strategies, detecting neural activity in high-resolution neural sensor recordings and then attributing them to their corresponding source neurons correctly, namely the process of spike sorting, has been prevailing so far. Support from ever-improving recording techniques and sophisticated algorithms for extracting worthwhile information and abundance in clustering procedures turned spike sorting into an indispensable tool in electrophysiological analysis. This review attempts to illustrate that in all stages of spike sorting algorithms, the past 5 years innovations' brought about concepts, results, and questions worth sharing with even the non-expert user community. By thoroughly inspecting latest innovations in the field of neural sensors, recording procedures, and various spike sorting strategies, a skeletonization of relevant knowledge lays here, with an initiative to get one step closer to the original objective: deciphering and building in the sense of neural transcript.
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Affiliation(s)
- Réka Barbara Bod
- Laboratory of Experimental Neurophysiology, Department of Physiology, Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Târgu Mureş, Târgu Mureş, Romania
| | - János Rokai
- Integrative Neuroscience Group, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
- School of PhD Studies, Semmelweis University, Budapest, Hungary
| | - Domokos Meszéna
- Integrative Neuroscience Group, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Richárd Fiáth
- Integrative Neuroscience Group, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - István Ulbert
- Integrative Neuroscience Group, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Gergely Márton
- Integrative Neuroscience Group, Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
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Balakrishnan G, Song J, Mou C, Bettinger CJ. Recent Progress in Materials Chemistry to Advance Flexible Bioelectronics in Medicine. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106787. [PMID: 34751987 PMCID: PMC8917047 DOI: 10.1002/adma.202106787] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/15/2021] [Indexed: 05/09/2023]
Abstract
Designing bioelectronic devices that seamlessly integrate with the human body is a technological pursuit of great importance. Bioelectronic medical devices that reliably and chronically interface with the body can advance neuroscience, health monitoring, diagnostics, and therapeutics. Recent major efforts focus on investigating strategies to fabricate flexible, stretchable, and soft electronic devices, and advances in materials chemistry have emerged as fundamental to the creation of the next generation of bioelectronics. This review summarizes contemporary advances and forthcoming technical challenges related to three principal components of bioelectronic devices: i) substrates and structural materials, ii) barrier and encapsulation materials, and iii) conductive materials. Through notable illustrations from the literature, integration and device fabrication strategies and associated challenges for each material class are highlighted.
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Affiliation(s)
| | - Jiwoo Song
- Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA
| | - Chenchen Mou
- Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA
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Flexible Liquid Crystal Polymer Technologies from Microwave to Terahertz Frequencies. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27041336. [PMID: 35209131 PMCID: PMC8877632 DOI: 10.3390/molecules27041336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/04/2022] [Accepted: 02/06/2022] [Indexed: 12/03/2022]
Abstract
With the emergence of fifth-generation (5G) cellular networks, millimeter-wave (mmW) and terahertz (THz) frequencies have attracted ever-growing interest for advanced wireless applications. The traditional printed circuit board materials have become uncompetitive at such high frequencies due to their high dielectric loss and large water absorption rates. As a promising high-frequency alternative, liquid crystal polymers (LCPs) have been widely investigated for use in circuit devices, chip integration, and module packaging over the last decade due to their low loss tangent up to 1.8 THz and good hermeticity. The previous review articles have summarized the chemical properties of LCP films, flexible LCP antennas, and LCP-based antenna-in-package and system-in-package technologies for 5G applications, although these articles did not discuss synthetic LCP technologies. In addition to wireless applications, the attractive mechanical, chemical, and thermal properties of LCP films enable interesting applications in micro-electro-mechanical systems (MEMS), biomedical electronics, and microfluidics, which have not been summarized to date. Here, a comprehensive review of flexible LCP technologies covering electric circuits, antennas, integration and packaging technologies, front-end modules, MEMS, biomedical devices, and microfluidics from microwave to THz frequencies is presented for the first time, which gives a broad introduction for those outside or just entering the field and provides perspective and breadth for those who are well established in the field.
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Otte E, Vlachos A, Asplund M. Engineering strategies towards overcoming bleeding and glial scar formation around neural probes. Cell Tissue Res 2022; 387:461-477. [PMID: 35029757 PMCID: PMC8975777 DOI: 10.1007/s00441-021-03567-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/17/2021] [Indexed: 12/15/2022]
Abstract
Neural probes are sophisticated electrophysiological tools used for intra-cortical recording and stimulation. These microelectrode arrays, designed to penetrate and interface the brain from within, contribute at the forefront of basic and clinical neuroscience. However, one of the challenges and currently most significant limitations is their ‘seamless’ long-term integration into the surrounding brain tissue. Following implantation, which is typically accompanied by bleeding, the tissue responds with a scarring process, resulting in a gliotic region closest to the probe. This glial scarring is often associated with neuroinflammation, neurodegeneration, and a leaky blood–brain interface (BBI). The engineering progress on minimizing this reaction in the form of improved materials, microfabrication, and surgical techniques is summarized in this review. As research over the past decade has progressed towards a more detailed understanding of the nature of this biological response, it is time to pose the question: Are penetrating probes completely free from glial scarring at all possible?
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Baek C, Kim S, Jang JW, Jung Y, Choi GJ, Shim S, Yun S, Seo K, Song YK, Kim SJ, Seo JM. Investigation of stereotactic surgery for avian brain stimulation by a fully implanted wireless system. Neurosurg Focus 2021; 49:E10. [PMID: 32610289 DOI: 10.3171/2020.4.focus2025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/14/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The authors' goal was to study avian motor brain mapping via wireless stimulation to induce certain behaviors. In this paper, the authors propose an electrode design that is suitable for avian brain stimulation as well as a stereotactic implant procedure for the proposed electrode. METHODS An appropriate breed for avian brain study was chosen. A fully implantable remote-controlled electrical stimulation system was inserted to minimize discomfort. A suitable electrode design and stereotactic surgery method based on the electrode design were investigated. RESULTS Using a wireless stimulation system, flapping and rotation behaviors were induced by stimulating the ventral part of the nucleus intercollicularis and formatio reticularis medialis mesencephali both on the ground and during flight. CONCLUSIONS The authors were able to implant the entire brain stimulation system inside the avian body without any surgical complications. Postoperative observations suggested that the bird did not find the implant uncomfortable.
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Affiliation(s)
| | - Sunhyo Kim
- 2Veterinary Clinical Sciences, Seoul National University, Seoul; and
| | - Jung-Woo Jang
- 3Department of Nano Science and Technology, Seoul National University, Suwon, South Korea
| | - Younginha Jung
- 3Department of Nano Science and Technology, Seoul National University, Suwon, South Korea
| | | | - Shinyong Shim
- Departments of1Electrical and Computer Engineering and
| | | | - Kangmoon Seo
- 2Veterinary Clinical Sciences, Seoul National University, Seoul; and
| | - Yoon-Kyu Song
- 3Department of Nano Science and Technology, Seoul National University, Suwon, South Korea
| | - Sung June Kim
- Departments of1Electrical and Computer Engineering and
| | - Jong-Mo Seo
- Departments of1Electrical and Computer Engineering and
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12
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Rihani R, Tasnim N, Javed M, Usoro JO, D'Souza TM, Ware TH, Pancrazio JJ. Liquid Crystalline Polymers: Opportunities to Shape Neural Interfaces. Neuromodulation 2021; 25:1259-1267. [PMID: 33501705 DOI: 10.1111/ner.13364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/21/2020] [Accepted: 01/05/2021] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Polymers have emerged as constituent materials for the creation of microscale neural interfaces; however, limitations regarding water permeability, delamination, and material degradation impact polymeric device robustness. Liquid crystal polymers (LCPs) have molecular order like a solid but with the fluidity of a liquid, resulting in a unique material, with properties including low water permeability, chemical inertness, and mechanical toughness. The objective of this article is to review the state-of-the-art regarding the use of LCPs in neural interface applications and discuss challenges and opportunities where this class of materials can advance the field of neural interfaces. MATERIALS AND METHODS This review article focuses on studies that leverage LCP materials to interface with the nervous system in vivo. A comprehensive literature search was performed using PubMed, Web of Science (Clarivate Analytics), and Google Scholar. RESULTS There have been recent efforts to create neural interfaces that leverage the material advantages of LCPs. The literature offers examples of LCP as a basis for implantable medical devices and neural interfaces in the form of planar electrode arrays for retinal prosthetic, electrocorticography applications, and cuff-like structures for interfacing the peripheral nerve. In addition, there have been efforts to create penetrating intracortical devices capable of microstimulation and resolution of biopotentials. Recent work with a subclass of LCPs, namely liquid crystal elastomers, demonstrates that it is possible to create devices with features that deploy away from a central implantation site to interface with a volume of tissue while offering the possibility of minimizing tissue damage. CONCLUSION We envision the creation of novel microscale neural interfaces that leverage the physical properties of LCPs and have the capability of deploying within neural tissue for enhanced integration and performance.
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Affiliation(s)
- Rashed Rihani
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Nishat Tasnim
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Mahjabeen Javed
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.,Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
| | - Joshua O Usoro
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Tania M D'Souza
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
| | - Taylor H Ware
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.,Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA.,Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
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Choi GJ, Seo JM, Song YK, Kim SJ, Jang J, Kim S, Baek C, Yun S, Shim S, Seo J, Jung Y, Seo K. A Fully Implantable Wireless Stimulation System for Pigeon Navigation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:5310-5313. [PMID: 31947055 DOI: 10.1109/embc.2019.8857039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Navigation of freely moving animals has been studied for potential application to emergency situations and hazardous environments. A fully implantable stimulation system for remote animal navigation was proposed and applied to living pigeons. The animal navigation system, consisting of an external controller and a neural stimulator, was designed based on the anatomy of the pigeons. Depth electrodes were fabricated based on the anatomy of target pigeon brain regions. The fabricated neural stimulators received data wirelessly from the external controller and generated biphasic current pulses with preset parameters of amplitude, duration, and rate. The average impedance of the fabricated electrodes was 12.0∠-13.05° kΩ at 1 kHz. The neural stimulator was implanted on the dorsal side, and the depth electrodes were inserted into the formatio reticularis medialis mesencephali (FRM). When successive current pulses with an amplitude of 400 μA, a rate of 58 Hz, and a duration of 80 μs were applied to the target regions at 0.85 s intervals, turning/circling behaviors were induced for 6.2 s. The feasibility of the proposed wireless stimulation system was demonstrated in vivo.
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Implantable electrical stimulation bioreactor with liquid crystal polymer-based electrodes for enhanced bone regeneration at mandibular large defects in rabbit. Med Biol Eng Comput 2019; 58:383-399. [PMID: 31853774 DOI: 10.1007/s11517-019-02046-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 09/05/2019] [Indexed: 02/07/2023]
Abstract
The osseous regeneration of large bone defects is still a major clinical challenge in maxillofacial and orthopedic surgery. Previous studies demonstrated that biphasic electrical stimulation (ES) stimulates bone formation; however, polyimide electrode should be removed after regeneration. This study presents an implantable electrical stimulation bioreactor with electrodes based on liquid crystal polymer (LCP), which can be permanently implanted due to excellent biocompatibility to bone tissue. The bioreactor was implanted into a critical-sized bone defect and subjected to ES for one week, where bone regeneration was evaluated four weeks after surgery using micro-CT. The effect of ES via the bioreactor was compared with a sham control group and a positive control group that received recombinant human bone morphogenetic protein (rhBMP)-2 (20 μg). New bone volume per tissue volume (BV/TV) in the ES and rhBMP-2 groups increased to 132% (p < 0.05) and 174% (p < 0.01), respectively, compared to that in the sham control group. In the histological evaluation, there was no inflammation within the bone defects and adjacent to LCP in all the groups. This study showed that the ES bioreactor with LCP electrodes could enhance bone regeneration at large bone defects, where LCP can act as a mechanically resistant outer box without inflammation. Graphical abstract To enhance bone regeneration, a bioreactor comprising collagen sponge and liquid crystal polymer-based electrode was implanted in the bone defect. Within the defect, electrical current pulses having biphasic waveform were applied from the implanted bioreactor.
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Choi GJ, Jang J, Kang S, Shim S, Baek C, Kim B, Park Y, Kim S, Jung Y, Seo K, Seo JM, Song YK, Kim SJ. Locomotion Control of Pigeons using Polymer-based Deep Brain Electrodes. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2019; 2018:1871-1874. [PMID: 30440761 DOI: 10.1109/embc.2018.8512684] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This paper describes the electrical modulation of locomotion in pigeons using deep brain electrodes. Polymer-based depth electrodes with four channels were fabricated. Based on the location of the nucleus intercollicularis (ICo), the shanks of the depth electrodes were designed to be a length of 11 mm. After the implantation of the depth electrode into the ICo region of the brain, it was connected by wires to a custom-made stimulator, and biphasic current pulses were delivered. Current pulses with an amplitude of 0.5 mA, a rate of 58.0 Hz, and a duration of $320\mu \mathrm{s} $s were applied for 0.5 s. When the ICo region was electrically stimulated, taking-off behavior was successfully induced for 0.4 s. Induction of taking-off behavior by electrical stimulation, when coupled to control of turning and running forward locomotions, may contribute to the development of remote flight-control system of freely moving pigeon.
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Kim C, Jeong J, Kim SJ. Recent Progress on Non-Conventional Microfabricated Probes for the Chronic Recording of Cortical Neural Activity. SENSORS (BASEL, SWITZERLAND) 2019; 19:E1069. [PMID: 30832357 PMCID: PMC6427797 DOI: 10.3390/s19051069] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 02/06/2023]
Abstract
Microfabrication technology for cortical interfaces has advanced rapidly over the past few decades for electrophysiological studies and neuroprosthetic devices offering the precise recording and stimulation of neural activity in the cortex. While various cortical microelectrode arrays have been extensively and successfully demonstrated in animal and clinical studies, there remains room for further improvement of the probe structure, materials, and fabrication technology, particularly for high-fidelity recording in chronic implantation. A variety of non-conventional probes featuring unique characteristics in their designs, materials and fabrication methods have been proposed to address the limitations of the conventional standard shank-type ("Utah-" or "Michigan-" type) devices. Such non-conventional probes include multi-sided arrays to avoid shielding and increase recording volumes, mesh- or thread-like arrays for minimized glial scarring and immune response, tube-type or cylindrical probes for three-dimensional (3D) recording and multi-modality, folded arrays for high conformability and 3D recording, self-softening or self-deployable probes for minimized tissue damage and extensions of the recording sites beyond gliosis, nanostructured probes to reduce the immune response, and cone-shaped electrodes for promoting tissue ingrowth and long-term recording stability. Herein, the recent progress with reference to the many different types of non-conventional arrays is reviewed while highlighting the challenges to be addressed and the microfabrication techniques necessary to implement such features.
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Affiliation(s)
- Chaebin Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea.
| | - Joonsoo Jeong
- Department of Biomedical Engineering, School of Medicine, Pusan National University, Yangsan 50612, Korea.
| | - Sung June Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea.
- Institute on Aging, College of Medicine, Seoul National University, Seoul 08826, Korea.
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