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Oldroyd P, Hadwe SE, Barone DG, Malliaras GG. Thin-film implants for bioelectronic medicine. MRS BULLETIN 2024; 49:1045-1058. [PMID: 39397879 PMCID: PMC11469980 DOI: 10.1557/s43577-024-00786-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 08/01/2024] [Indexed: 10/15/2024]
Abstract
This article is based on the MRS Mid-Career Researcher Award "for outstanding contributions to the fundamentals and development of organic electronic materials and their application in biology and medicine" presentation given by George G. Malliaras, University of Cambridge, at the 2023 MRS Spring Meeting in San Francisco, Calif.Bioelectronic medicine offers a revolutionary approach to treating disease by stimulating the body with electricity. While current devices show safety and efficacy, limitations, including bulkiness, invasiveness, and scalability, hinder their wider application. Thin-film implants promise to overcome these limitations. Made using microfabrication technologies, these implants conform better to neural tissues, reduce tissue damage and foreign body response, and provide high-density, multimodal interfaces with the body. This article explores how thin-film implants using organic materials and novel designs may contribute to disease management, intraoperative monitoring, and brain mapping applications. Additionally, the technical challenges to be addressed for this technology to succeed are discussed. Graphical abstract
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Affiliation(s)
- Poppy Oldroyd
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
| | - Salim El Hadwe
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Damiano G. Barone
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - George G. Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK
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2
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Yoo S, Kim M, Choi C, Kim DH, Cha GD. Soft Bioelectronics for Neuroengineering: New Horizons in the Treatment of Brain Tumor and Epilepsy. Adv Healthc Mater 2024; 13:e2303563. [PMID: 38117136 DOI: 10.1002/adhm.202303563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/23/2023] [Indexed: 12/21/2023]
Abstract
Soft bioelectronic technologies for neuroengineering have shown remarkable progress, which include novel soft material technologies and device design strategies. Such technological advances that are initiated from fundamental brain science are applied to clinical neuroscience and provided meaningful promises for significant improvement in the diagnosis efficiency and therapeutic efficacy of various brain diseases recently. System-level integration strategies in consideration of specific disease circumstances can enhance treatment effects further. Here, recent advances in soft implantable bioelectronics for neuroengineering, focusing on materials and device designs optimized for the treatment of intracranial disease environments, are reviewed. Various types of soft bioelectronics for neuroengineering are categorized and exemplified first, and then details for the sensing and stimulating device components are explained. Next, application examples of soft implantable bioelectronics to clinical neuroscience, particularly focusing on the treatment of brain tumor and epilepsy are reviewed. Finally, an ideal system of soft intracranial bioelectronics such as closed-loop-type fully-integrated systems is presented, and the remaining challenges for their clinical translation are discussed.
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Affiliation(s)
- Seungwon Yoo
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, 08826, Republic of Korea
| | - Minjeong Kim
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, 08826, Republic of Korea
| | - Changsoon Choi
- Center for Opto-Electronic Materials and Devices, Post-silicon Semiconductor Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Dae-Hyeong Kim
- Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Gi Doo Cha
- Department of Systems Biotechnology, Chung-Ang University, Anseong-si, Gyeonggi-do, 17546, Republic of Korea
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3
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Coles L, Ventrella D, Carnicer-Lombarte A, Elmi A, Troughton JG, Mariello M, El Hadwe S, Woodington BJ, Bacci ML, Malliaras GG, Barone DG, Proctor CM. Origami-inspired soft fluidic actuation for minimally invasive large-area electrocorticography. Nat Commun 2024; 15:6290. [PMID: 39060241 PMCID: PMC11282215 DOI: 10.1038/s41467-024-50597-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 07/16/2024] [Indexed: 07/28/2024] Open
Abstract
Electrocorticography is an established neural interfacing technique wherein an array of electrodes enables large-area recording from the cortical surface. Electrocorticography is commonly used for seizure mapping however the implantation of large-area electrocorticography arrays is a highly invasive procedure, requiring a craniotomy larger than the implant area to place the device. In this work, flexible thin-film electrode arrays are combined with concepts from soft robotics, to realize a large-area electrocorticography device that can change shape via integrated fluidic actuators. We show that the 32-electrode device can be packaged using origami-inspired folding into a compressed state and implanted through a small burr-hole craniotomy, then expanded on the surface of the brain for large-area cortical coverage. The implantation, expansion, and recording functionality of the device is confirmed in-vitro and in porcine in-vivo models. The integration of shape actuation into neural implants provides a clinically viable pathway to realize large-area neural interfaces via minimally invasive surgical techniques.
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Affiliation(s)
- Lawrence Coles
- Department of Engineering, University of Cambridge, Cambridge, UK
- Institute of Biomedical Engineering, Engineering Science Department, University of Oxford, Oxford, UK
| | - Domenico Ventrella
- Department of Veterinary Medical Sciences, Alma Mater Studiorum, University of Bologna, Ozzano dell'Emilia, Bologna, Italy
| | | | - Alberto Elmi
- Department of Veterinary Medical Sciences, Alma Mater Studiorum, University of Bologna, Ozzano dell'Emilia, Bologna, Italy
| | - Joe G Troughton
- Department of Engineering, University of Cambridge, Cambridge, UK
- Institute of Biomedical Engineering, Engineering Science Department, University of Oxford, Oxford, UK
| | - Massimo Mariello
- Institute of Biomedical Engineering, Engineering Science Department, University of Oxford, Oxford, UK
| | - Salim El Hadwe
- Department of Engineering, University of Cambridge, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Ben J Woodington
- Department of Engineering, University of Cambridge, Cambridge, UK
| | - Maria L Bacci
- Department of Veterinary Medical Sciences, Alma Mater Studiorum, University of Bologna, Ozzano dell'Emilia, Bologna, Italy
| | | | - Damiano G Barone
- Department of Engineering, University of Cambridge, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Christopher M Proctor
- Department of Engineering, University of Cambridge, Cambridge, UK.
- Institute of Biomedical Engineering, Engineering Science Department, University of Oxford, Oxford, UK.
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Londoño‐Ramírez H, Huang X, Cools J, Chrzanowska A, Brunner C, Ballini M, Hoffman L, Steudel S, Rolin C, Mora Lopez C, Genoe J, Haesler S. Multiplexed Surface Electrode Arrays Based on Metal Oxide Thin-Film Electronics for High-Resolution Cortical Mapping. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2308507. [PMID: 38145348 PMCID: PMC10933637 DOI: 10.1002/advs.202308507] [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: 11/08/2023] [Revised: 12/15/2023] [Indexed: 12/26/2023]
Abstract
Electrode grids are used in neuroscience research and clinical practice to record electrical activity from the surface of the brain. However, existing passive electrocorticography (ECoG) technologies are unable to offer both high spatial resolution and wide cortical coverage, while ensuring a compact acquisition system. The electrode count and density are restricted by the fact that each electrode must be individually wired. This work presents an active micro-electrocorticography (µECoG) implant that tackles this limitation by incorporating metal oxide thin-film transistors (TFTs) into a flexible electrode array, allowing to address multiple electrodes through a single shared readout line. By combining the array with an incremental-ΔΣ readout integrated circuit (ROIC), the system is capable of recording from up to 256 electrodes virtually simultaneously, thanks to the implemented 16:1 time-division multiplexing scheme, offering lower noise levels than existing active µECoG arrays. In vivo validation is demonstrated acutely in mice by recording spontaneous activity and somatosensory evoked potentials over a cortical surface of ≈8×8 mm2 . The proposed neural interface overcomes the wiring bottleneck limiting ECoG arrays, holding promise as a powerful tool for improved mapping of the cerebral cortex and as an enabling technology for future brain-machine interfaces.
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Affiliation(s)
- Horacio Londoño‐Ramírez
- Department of Neuroscience, Leuven Brain InstituteKatholieke Universiteit (KU) LeuvenLeuven3001Belgium
- Neuroelectronics Research Flanders (NERF)Leuven3001Belgium
- imecLeuven3001Belgium
- Flanders Institute for Biotechnology (VIB)Gent9052Belgium
| | - Xiaohua Huang
- imecLeuven3001Belgium
- Department of Electrical Engineering (ESAT)Katholieke Universiteit (KU) LeuvenLeuven3001Belgium
| | - Jordi Cools
- Neuroelectronics Research Flanders (NERF)Leuven3001Belgium
- imecLeuven3001Belgium
- Flanders Institute for Biotechnology (VIB)Gent9052Belgium
- Present address:
Thermo Fisher Scientific3001LeuvenBelgium
| | - Anna Chrzanowska
- Neuroelectronics Research Flanders (NERF)Leuven3001Belgium
- Flanders Institute for Biotechnology (VIB)Gent9052Belgium
- Department of BiologyKatholieke Universiteit (KU) LeuvenLeuven3001Belgium
| | - Clément Brunner
- Department of Neuroscience, Leuven Brain InstituteKatholieke Universiteit (KU) LeuvenLeuven3001Belgium
- Neuroelectronics Research Flanders (NERF)Leuven3001Belgium
- Flanders Institute for Biotechnology (VIB)Gent9052Belgium
| | - Marco Ballini
- imecLeuven3001Belgium
- Present address:
Microphone Business Unit, TDK InvenSense20057MilanItaly
| | - Luis Hoffman
- Neuroelectronics Research Flanders (NERF)Leuven3001Belgium
- imecLeuven3001Belgium
- Present address:
Swave Photonics3001LeuvenBelgium
| | - Soeren Steudel
- imecLeuven3001Belgium
- Present address:
MICLEDI Microdisplays3001LeuvenBelgium
| | | | | | - Jan Genoe
- Department of Electrical Engineering (ESAT)Katholieke Universiteit (KU) LeuvenLeuven3001Belgium
| | - Sebastian Haesler
- Department of Neuroscience, Leuven Brain InstituteKatholieke Universiteit (KU) LeuvenLeuven3001Belgium
- Neuroelectronics Research Flanders (NERF)Leuven3001Belgium
- Flanders Institute for Biotechnology (VIB)Gent9052Belgium
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Paggi V, Fallegger F, Serex L, Rizzo O, Galan K, Giannotti A, Furfaro I, Zinno C, Bernini F, Micera S, Lacour SP. A soft, scalable and adaptable multi-contact cuff electrode for targeted peripheral nerve modulation. Bioelectron Med 2024; 10:6. [PMID: 38350988 PMCID: PMC10865708 DOI: 10.1186/s42234-023-00137-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/10/2023] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND Cuff electrodes target various nerves throughout the body, providing neuromodulation therapies for motor, sensory, or autonomic disorders. However, when using standard, thick silicone cuffs, fabricated in discrete circular sizes, complications may arise, namely cuff displacement or nerve compression, due to a poor adaptability to variable nerve shapes and sizes encountered in vivo. Improvements in cuff design, materials, closing mechanism and surgical approach are necessary to overcome these issues. METHODS In this work, we propose a microfabricated multi-channel silicone-based soft cuff electrode with a novel easy-to-implant and size-adaptable design and evaluate a number of essential features such as nerve-cuff contact, nerve compression, cuff locking stability, long-term integration and stimulation selectivity. We also compared performance to that of standard fixed-size cuffs. RESULTS The belt-like cuff made of 150 μm thick silicone membranes provides a stable and pressure-free conformal contact, independently of nerve size variability, combined with a straightforward implantation procedure. The adaptable design and use of soft materials lead to limited scarring and demyelination after 6-week implantation. In addition, multi-contact designs, ranging from 6 to 16 electrodes, allow for selective stimulation in models of rat and pig sciatic nerve, achieving targeted activation of up to 5 hindlimb muscles. CONCLUSION These results suggest a promising alternative to classic fixed-diameter cuffs and may facilitate the adoption of soft, adaptable cuffs in clinical settings.
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Affiliation(s)
- Valentina Paggi
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Florian Fallegger
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | | | - Olivier Rizzo
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- Bertarelli Foundation Chair in Translational NeuroEngineering, Neuro-X Institute, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Katia Galan
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Alice Giannotti
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Ivan Furfaro
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
| | - Ciro Zinno
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Fabio Bernini
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Silvestro Micera
- Bertarelli Foundation Chair in Translational NeuroEngineering, Neuro-X Institute, École Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland
- The BioRobotics Institute and Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Stéphanie P Lacour
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Geneva, Switzerland.
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6
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Lee JM, Pyo YW, Kim YJ, Hong JH, Jo Y, Choi W, Lin D, Park HG. The ultra-thin, minimally invasive surface electrode array NeuroWeb for probing neural activity. Nat Commun 2023; 14:7088. [PMID: 37925553 PMCID: PMC10625630 DOI: 10.1038/s41467-023-42860-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/24/2023] [Indexed: 11/06/2023] Open
Abstract
Electrophysiological recording technologies can provide valuable insights into the functioning of the central and peripheral nervous systems. Surface electrode arrays made of soft materials or implantable multi-electrode arrays with high electrode density have been widely utilized as neural probes. However, neither of these probe types can simultaneously achieve minimal invasiveness and robust neural signal detection. Here, we present an ultra-thin, minimally invasive neural probe (the "NeuroWeb") consisting of hexagonal boron nitride and graphene, which leverages the strengths of both surface electrode array and implantable multi-electrode array. The NeuroWeb open lattice structure with a total thickness of 100 nm demonstrates high flexibility and strong adhesion, establishing a conformal and tight interface with the uneven mouse brain surface. In vivo electrophysiological recordings show that NeuroWeb detects stable single-unit activity of neurons with high signal-to-noise ratios. Furthermore, we investigate neural interactions between the somatosensory cortex and the cerebellum using transparent dual NeuroWebs and optical stimulation, and measure the times of neural signal transmission between the brain regions depending on the pathway. Therefore, NeuroWeb can be expected to pave the way for understanding complex brain networks with optical and electrophysiological mapping of the brain.
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Affiliation(s)
- Jung Min Lee
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea
| | - Young-Woo Pyo
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
| | - Yeon Jun Kim
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
| | - Jin Hee Hong
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul, 02841, Republic of Korea
| | - Yonghyeon Jo
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul, 02841, Republic of Korea
| | - Wonshik Choi
- Department of Physics, Korea University, Seoul, 02841, Republic of Korea
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul, 02841, Republic of Korea
| | - Dingchang Lin
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Hong-Gyu Park
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National University, Seoul, 08826, Republic of Korea.
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7
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Ji B, Sun F, Guo J, Zhou Y, You X, Fan Y, Wang L, Xu M, Zeng W, Liu J, Wang M, Hu H, Chang H. Brainmask: an ultrasoft and moist micro-electrocorticography electrode for accurate positioning and long-lasting recordings. MICROSYSTEMS & NANOENGINEERING 2023; 9:126. [PMID: 37829160 PMCID: PMC10564857 DOI: 10.1038/s41378-023-00597-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/11/2023] [Accepted: 09/02/2023] [Indexed: 10/14/2023]
Abstract
Bacterial cellulose (BC), a natural biomaterial synthesized by bacteria, has a unique structure of a cellulose nanofiber-weaved three-dimensional reticulated network. BC films can be ultrasoft with sufficient mechanical strength, strong water absorption and moisture retention and have been widely used in facial masks. These films have the potential to be applied to implantable neural interfaces due to their conformality and moisture, which are two critical issues for traditional polymer or silicone electrodes. In this work, we propose a micro-electrocorticography (micro-ECoG) electrode named "Brainmask", which comprises a BC film as the substrate and separated multichannel parylene-C microelectrodes bonded on the top surface. Brainmask can not only guarantee the precise position of microelectrode sites attached to any nonplanar epidural surface but also improve the long-lasting signal quality during acute implantation with an exposed cranial window for at least one hour, as well as the in vivo recording validated for one week. This novel ultrasoft and moist device stands as a next-generation neural interface regardless of complex surface or time of duration.
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Affiliation(s)
- Bowen Ji
- Unmanned System Research Institute, Northwestern Polytechnical University, Xi’an, 710072 China
- Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an, 710072 China
- Collaborative Innovation Center of Northwestern Polytechnical University, Shanghai, 201108 China
| | - Fanqi Sun
- Unmanned System Research Institute, Northwestern Polytechnical University, Xi’an, 710072 China
- Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an, 710072 China
- Collaborative Innovation Center of Northwestern Polytechnical University, Shanghai, 201108 China
| | - Jiecheng Guo
- Institute of Medical Research, Northwestern Polytechnical University, Xi’an, 710072 China
| | - Yuhao Zhou
- Unmanned System Research Institute, Northwestern Polytechnical University, Xi’an, 710072 China
- Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an, 710072 China
- Collaborative Innovation Center of Northwestern Polytechnical University, Shanghai, 201108 China
| | - Xiaoli You
- Unmanned System Research Institute, Northwestern Polytechnical University, Xi’an, 710072 China
- Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an, 710072 China
- Collaborative Innovation Center of Northwestern Polytechnical University, Shanghai, 201108 China
| | - Ye Fan
- College of Electronics and Information, Hangzhou Dianzi University, Hangzhou, 310018 China
| | - Longchun Wang
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Department of Micro/Nano Electronics, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Mengfei Xu
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Department of Micro/Nano Electronics, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Wen Zeng
- Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an, 710072 China
| | - Jingquan Liu
- National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Department of Micro/Nano Electronics, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Minghao Wang
- College of Electronics and Information, Hangzhou Dianzi University, Hangzhou, 310018 China
| | - Huijing Hu
- Institute of Medical Research, Northwestern Polytechnical University, Xi’an, 710072 China
| | - Honglong Chang
- Ministry of Education Key Laboratory of Micro and Nano Systems for Aerospace, School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an, 710072 China
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8
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Fallegger F, Trouillet A, Coen FV, Schiavone G, Lacour SP. A low-profile electromechanical packaging system for soft-to-flexible bioelectronic interfaces. APL Bioeng 2023; 7:036109. [PMID: 37600068 PMCID: PMC10439817 DOI: 10.1063/5.0152509] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 08/02/2023] [Indexed: 08/22/2023] Open
Abstract
Interfacing the human body with the next generation of electronics requires technological advancement in designing and producing bioelectronic circuits. These circuits must integrate electrical functionality while simultaneously addressing limitations in mechanical compliance and dynamics, biocompatibility, and consistent, scalable manufacturing. The combination of mechanically disparate materials ranging from elastomers to inorganic crystalline semiconductors calls for modular designs with reliable and scalable electromechanical connectors. Here, we report on a novel interconnection solution for soft-to-flexible bioelectronic interfaces using a patterned and machined flexible printed circuit board, which we term FlexComb, interfaced with soft transducing systems. Using a simple assembly process, arrays of protruding "fingers" bearing individual electrical terminals are laser-machined on a standard flexible printed circuit board to create a comb-like structure, namely, the FlexComb. A matching pattern is also machined in the soft system to host and interlock electromechanically the FlexComb connections via a soft electrically conducting composite. We examine the electrical and electromechanical properties of the interconnection and demonstrate the versatility and scalability of the method through various customized submillimetric designs. In a pilot in vivo study, we validate the stability and compatibility of the FlexComb technology in a subdural electrocorticography system implanted for 6 months on the auditory cortex of a minipig. The FlexComb provides a reliable and simple technique to bond and connect soft transducing systems with flexible or rigid electronic boards, which should find many implementations in soft robotics and wearable and implantable bioelectronics.
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Affiliation(s)
- Florian Fallegger
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Alix Trouillet
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Florent-Valéry Coen
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | | | - Stéphanie P. Lacour
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne, Geneva, Switzerland
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9
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Song S, Fallegger F, Trouillet A, Kim K, Lacour SP. Deployment of an electrocorticography system with a soft robotic actuator. Sci Robot 2023; 8:eadd1002. [PMID: 37163609 DOI: 10.1126/scirobotics.add1002] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Electrocorticography (ECoG) is a minimally invasive approach frequently used clinically to map epileptogenic regions of the brain and facilitate lesion resection surgery and increasingly explored in brain-machine interface applications. Current devices display limitations that require trade-offs among cortical surface coverage, spatial electrode resolution, aesthetic, and risk consequences and often limit the use of the mapping technology to the operating room. In this work, we report on a scalable technique for the fabrication of large-area soft robotic electrode arrays and their deployment on the cortex through a square-centimeter burr hole using a pressure-driven actuation mechanism called eversion. The deployable system consists of up to six prefolded soft legs, and it is placed subdurally on the cortex using an aqueous pressurized solution and secured to the pedestal on the rim of the small craniotomy. Each leg contains soft, microfabricated electrodes and strain sensors for real-time deployment monitoring. In a proof-of-concept acute surgery, a soft robotic electrode array was successfully deployed on the cortex of a minipig to record sensory cortical activity. This soft robotic neurotechnology opens promising avenues for minimally invasive cortical surgery and applications related to neurological disorders such as motor and sensory deficits.
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Affiliation(s)
- Sukho Song
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland
- Laboratory of Sustainability Robotics, Swiss Federal Laboratories for Materials Science and Technology (Empa), 8600 Dübendorf, Switzerland
| | - Florian Fallegger
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland
| | - Alix Trouillet
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland
| | - Kyungjin Kim
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland
- Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - Stéphanie P Lacour
- Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland
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10
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Branco MP, Geukes SH, Aarnoutse EJ, Ramsey NF, Vansteensel MJ. Nine decades of electrocorticography: A comparison between epidural and subdural recordings. Eur J Neurosci 2023; 57:1260-1288. [PMID: 36843389 DOI: 10.1111/ejn.15941] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 02/10/2023] [Accepted: 02/18/2023] [Indexed: 02/28/2023]
Abstract
In recent years, electrocorticography (ECoG) has arisen as a neural signal recording tool in the development of clinically viable neural interfaces. ECoG electrodes are generally placed below the dura mater (subdural) but can also be placed on top of the dura (epidural). In deciding which of these modalities best suits long-term implants, complications and signal quality are important considerations. Conceptually, epidural placement may present a lower risk of complications as the dura is left intact but also a lower signal quality due to the dura acting as a signal attenuator. The extent to which complications and signal quality are affected by the dura, however, has been a matter of debate. To improve our understanding of the effects of the dura on complications and signal quality, we conducted a literature review. We inventorized the effect of the dura on signal quality, decodability and longevity of acute and chronic ECoG recordings in humans and non-human primates. Also, we compared the incidence and nature of serious complications in studies that employed epidural and subdural ECoG. Overall, we found that, even though epidural recordings exhibit attenuated signal amplitude over subdural recordings, particularly for high-density grids, the decodability of epidural recorded signals does not seem to be markedly affected. Additionally, we found that the nature of serious complications was comparable between epidural and subdural recordings. These results indicate that both epidural and subdural ECoG may be suited for long-term neural signal recordings, at least for current generations of clinical and high-density ECoG grids.
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Affiliation(s)
- Mariana P Branco
- Department of Neurology and Neurosurgery, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Simon H Geukes
- Department of Neurology and Neurosurgery, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Erik J Aarnoutse
- Department of Neurology and Neurosurgery, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Nick F Ramsey
- Department of Neurology and Neurosurgery, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Mariska J Vansteensel
- Department of Neurology and Neurosurgery, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
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11
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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.
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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.
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12
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Shur M, Akouissi O, Rizzo O, Colin DJ, Kolinski JM, Lacour SP. Revealing the complexity of ultra-soft hydrogel re-swelling inside the brain. Biomaterials 2023; 294:122024. [PMID: 36716587 DOI: 10.1016/j.biomaterials.2023.122024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/12/2022] [Accepted: 01/20/2023] [Indexed: 01/27/2023]
Abstract
The brain is an ultra-soft viscoelastic matrix. Sub-kPa hydrogels match the brain's mechanical properties but are challenging to manipulate in an implantable format. We propose a simple fabrication and processing sequence, consisting of de-hydration, patterning, implantation, and re-hydration steps, to deliver brain-like hydrogel implants into the nervous tissue. We monitored in real-time the ultra-soft hydrogel re-swelling kinetics in vivo using microcomputed tomography, achieved by embedding gold nanoparticles inside the hydrogel for contrast enhancement. We found that re-swelling in vivo strongly depends on the implant geometry and water availability at the hydrogel-tissue interface. Buckling of the implant inside the brain occurs when the soft implant is tethered to the cranium. Finite-element and analytical models reveal how the shank geometry, modulus and anchoring govern in vivo buckling. Taken together, these considerations on re-swelling kinetics of hydrogel constructs, implant geometry and soft implant-tissue mechanical interplay can guide the engineering of biomimetic brain implants.
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Affiliation(s)
- Michael Shur
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, École Polytechnique Fedérale de Lausanne (EPFL), 1202, Geneva, Switzerland
| | - Outman Akouissi
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, École Polytechnique Fedérale de Lausanne (EPFL), 1202, Geneva, Switzerland; Bertarelli Foundation Chair in Translational Neuroengineering, Institute of Bioengineering, Center for Neuroprosthetics, École Polytechnique Fédérale de Lausanne (EPFL), 1202, Geneva, Switzerland
| | - Olivier Rizzo
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, École Polytechnique Fedérale de Lausanne (EPFL), 1202, Geneva, Switzerland
| | - Didier J Colin
- Preclinical Imaging Platform, Faculty of Medicine, University of Geneva, 1211, Geneva, Switzerland
| | - John M Kolinski
- Laboratory of Engineering Mechanics of Soft Interfaces, Institute of Mechanical Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Stéphanie P Lacour
- Bertarelli Foundation Chair in Neuroprosthetic Technology, Laboratory for Soft Bioelectronic Interfaces, Neuro-X Institute, École Polytechnique Fedérale de Lausanne (EPFL), 1202, Geneva, Switzerland.
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13
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Borda E, Medagoda DI, Airaghi Leccardi MJI, Zollinger EG, Ghezzi D. Conformable neural interface based on off-stoichiometry thiol-ene-epoxy thermosets. Biomaterials 2023; 293:121979. [PMID: 36586146 DOI: 10.1016/j.biomaterials.2022.121979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 11/29/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022]
Abstract
Off-stoichiometry thiol-ene-epoxy (OSTE+) thermosets show low permeability to gases and little absorption of dissolved molecules, allow direct low-temperature dry bonding without surface treatments, have a low Young's modulus, and can be manufactured via UV polymerisation. For these reasons, OSTE+ thermosets have recently gained attention for the rapid prototyping of microfluidic chips. Moreover, their compatibility with standard clean-room processes and outstanding mechanical properties make OSTE+ an excellent candidate as a novel material for neural implants. Here we exploit OSTE+ to manufacture a conformable multilayer micro-electrocorticography array with 16 platinum electrodes coated with platinum black. The mechanical properties allow conformability to curved surfaces such as the brain. The low permeability and strong adhesion between layers improve the stability of the device. Acute experiments in mice show the multimodal capacity of the array to record and stimulate the neural tissue by smoothly conforming to the mouse cortex. Devices are not cytotoxic, and immunohistochemistry stainings reveal only modest foreign body reaction after two and six weeks of chronic implantation. This work introduces OSTE+ as a promising material for implantable neural interfaces.
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Affiliation(s)
- Eleonora Borda
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Switzerland
| | - Danashi Imani Medagoda
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Switzerland
| | - Marta Jole Ildelfonsa Airaghi Leccardi
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Switzerland
| | - Elodie Geneviève Zollinger
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Switzerland
| | - Diego Ghezzi
- Medtronic Chair in Neuroengineering, Center for Neuroprosthetics and Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Switzerland.
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14
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Gupta A, Vardalakis N, Wagner FB. Neuroprosthetics: from sensorimotor to cognitive disorders. Commun Biol 2023; 6:14. [PMID: 36609559 PMCID: PMC9823108 DOI: 10.1038/s42003-022-04390-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 12/19/2022] [Indexed: 01/07/2023] Open
Abstract
Neuroprosthetics is a multidisciplinary field at the interface between neurosciences and biomedical engineering, which aims at replacing or modulating parts of the nervous system that get disrupted in neurological disorders or after injury. Although neuroprostheses have steadily evolved over the past 60 years in the field of sensory and motor disorders, their application to higher-order cognitive functions is still at a relatively preliminary stage. Nevertheless, a recent series of proof-of-concept studies suggest that electrical neuromodulation strategies might also be useful in alleviating some cognitive and memory deficits, in particular in the context of dementia. Here, we review the evolution of neuroprosthetics from sensorimotor to cognitive disorders, highlighting important common principles such as the need for neuroprosthetic systems that enable multisite bidirectional interactions with the nervous system.
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Affiliation(s)
- Ankur Gupta
- grid.462010.1Univ. Bordeaux, CNRS, IMN, UMR 5293, F-33000 Bordeaux, France
| | | | - Fabien B. Wagner
- grid.462010.1Univ. Bordeaux, CNRS, IMN, UMR 5293, F-33000 Bordeaux, France
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15
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Zhang F, Zhang L, Xia J, Zhao W, Dong S, Ye Z, Pan G, Luo J, Zhang S. Multimodal Electrocorticogram Active Electrode Array Based on Zinc Oxide-Thin Film Transistors. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2204467. [PMID: 36403238 PMCID: PMC9839861 DOI: 10.1002/advs.202204467] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/21/2022] [Indexed: 06/16/2023]
Abstract
Active electrocorticogram (ECoG) electrodes can amplify weak electrophysiological signals and improve anti-interference ability; however, traditional active electrodes are opaque and cannot realize photoelectric collaborative observation. In this study, an active and fully transparent ECoG array based on zinc oxide thin-film transistors (ZnO TFTs) is developed as a local neural signal amplifier for electrophysiological monitoring. The transparency of the proposed ECoG array is up to 85%, which is superior to that of the previously reported active electrode arrays. Various electrical characterizations have demonstrated its ability to record electrophysiological signals with a higher signal-to-noise ratio of 19.9 dB compared to the Au grid (13.2 dB). The high transparency of the ZnO-TFT electrode array allows the concurrent collection of high-quality electrophysiological signals (32.2 dB) under direct optical stimulation of the optogenetic mice brain. The ECoG array can also work under 7-Tesla magnetic resonance imaging to record local brain signals without affecting brain tissue imaging. As the most transparent active ECoG array to date, it provides a powerful multimodal tool for brain observation, including recording brain activity under synchronized optical modulation and 7-Tesla magnetic resonance imaging.
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Affiliation(s)
- Fan Zhang
- Key Laboratory of Biomedical Engineering of Ministry of EducationQiushi Academy for Advanced StudiesZhejiang Provincial Key Laboratory of Cardio‐Cerebral Vascular Detection Technology and Medicinal Effectiveness AppraisalZhejiang University38 Zheda RoadHangzhou310027China
| | - Luxi Zhang
- College of Information Science and Electronic EngineeringFrontier Center of Brain Science and Brain‐machine IntegrationCancer CenterZhejiang University38 Zheda RoadHangzhou310027China
| | - Jie Xia
- College of Information Science and Electronic EngineeringZhejiang University38 Zheda RoadHangzhou310027China
| | - Wanpeng Zhao
- College of Information Science and Electronic EngineeringZhejiang University38 Zheda RoadHangzhou310027China
| | - Shurong Dong
- College of Information Science and Electronic EngineeringFrontier Center of Brain Science and Brain‐machine IntegrationCancer CenterZhejiang University38 Zheda RoadHangzhou310027China
| | - Zhi Ye
- College of Information Science and Electronic EngineeringZhejiang University38 Zheda RoadHangzhou310027China
| | - Gang Pan
- College of Computer Science and TechnologyZhejiang University38 Zheda RoadHangzhou310027China
| | - Jikui Luo
- College of Information Science and Electronic EngineeringZhejiang University38 Zheda RoadHangzhou310027China
| | - Shaomin Zhang
- Key Laboratory of Biomedical Engineering of Ministry of EducationQiushi Academy for Advanced StudiesZhejiang Provincial Key Laboratory of Cardio‐Cerebral Vascular Detection Technology and Medicinal Effectiveness AppraisalZhejiang University38 Zheda RoadHangzhou310027China
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16
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Saghir S, Imenes K, Schiavone G. Integration of hydrogels in microfabrication processes for bioelectronic medicine: Progress and outlook. Front Bioeng Biotechnol 2023; 11:1150147. [PMID: 37034261 PMCID: PMC10079906 DOI: 10.3389/fbioe.2023.1150147] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 03/10/2023] [Indexed: 04/11/2023] Open
Abstract
Recent research aiming at the development of electroceuticals for the treatment of medical conditions such as degenerative diseases, cardiac arrhythmia and chronic pain, has given rise to microfabricated implanted bioelectronic devices capable of interacting with host biological tissues in synergistic modalities. Owing to their multimodal affinity to biological tissues, hydrogels have emerged as promising interface materials for bioelectronic devices. Here, we review the state-of-the-art and forefront in the techniques used by research groups for the integration of hydrogels into the microfabrication processes of bioelectronic devices, and present the manufacturability challenges to unlock their further clinical deployment.
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17
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Coles L, Oluwasanya PW, Karam N, Proctor CM. Fluidic enabled bioelectronic implants: opportunities and challenges. J Mater Chem B 2022; 10:7122-7131. [PMID: 35959561 PMCID: PMC9518646 DOI: 10.1039/d2tb00942k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/26/2022] [Indexed: 11/21/2022]
Abstract
Bioelectronic implants are increasingly facilitating novel strategies for clinical diagnosis and treatment. The integration of fluidic technologies into such implants enables new complementary routes for sensing and therapy alongside electrical interaction. Indeed, these two technologies, electrical and fluidic, can work synergistically in a bioelectronics implant towards the fabrication of a complete therapeutic platform. In this perspective article, the leading applications of fluidic enabled bioelectronic implants are highlighted and methods of operation and material choices are discussed. Furthermore, a forward-looking perspective is offered on emerging opportunities as well as critical materials and technological challenges.
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Affiliation(s)
- Lawrence Coles
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK.
| | - Pelumi W Oluwasanya
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK.
| | - Nuzli Karam
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK.
| | - Christopher M Proctor
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK.
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18
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Woodington BJ, Coles L, Rochford AE, Freeman P, Sawiak S, O'Neill SJK, Scherman OA, Barone DG, Proctor CM, Malliaras GG. X-Ray Markers for Thin Film Implants. Adv Healthc Mater 2022; 11:e2200739. [PMID: 35871265 PMCID: PMC11468128 DOI: 10.1002/adhm.202200739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/29/2022] [Indexed: 01/27/2023]
Abstract
Implantable electronic medical devices are used in functional mapping of the brain before surgery and to deliver neuromodulation for the treatment of neurological and neuropsychiatric disorders. Their electrode arrays are assembled by hand, and this leads to bulky form factors with limited flexibility and low electrode counts. Thin film implants, made using microfabrication techniques, are emerging as an attractive alternative, as they offer dramatically improved conformability and enable high density recording and stimulation. A major limitation of these devices, however, is that they are invisible to fluoroscopy, the most common method used to monitor the insertion of implantable electrodes. Here, the development of mechanically flexible X-ray markers using bismuth- and barium-infused elastomers is reported. Their X-ray attenuation properties in human cadavers are explored and it is shown that they are biocompatible in cell cultures. It is further shown that they do not distort magnetic resonance imaging images and their integration with thin film implants is demonstrated. This work removes a key barrier for the adoption of thin film implants in brain mapping and in neuromodulation.
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Affiliation(s)
- Ben J. Woodington
- Electrical Engineering DivisionDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
| | - Lawrence Coles
- Electrical Engineering DivisionDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
| | - Amy E. Rochford
- Electrical Engineering DivisionDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
| | - Paul Freeman
- Department of Veterinary MedicineUniversity of CambridgeCambridgeCB3 0ESUK
| | - Stephen Sawiak
- Department of Clinical NeurosciencesUniversity of CambridgeCambridgeCB2 0QQUK
| | - Stephen J. K. O'Neill
- Melville Laboratory for Polymer SynthesisYusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Oren A. Scherman
- Melville Laboratory for Polymer SynthesisYusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeCB2 1EWUK
| | - Damiano G. Barone
- Electrical Engineering DivisionDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
- Department of Clinical NeurosciencesUniversity of CambridgeCambridgeCB2 0QQUK
| | - Christopher M. Proctor
- Electrical Engineering DivisionDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
| | - George G. Malliaras
- Electrical Engineering DivisionDepartment of EngineeringUniversity of CambridgeCambridgeCB3 0FAUK
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19
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Hassan AR, Zhao Z, Ferrero JJ, Cea C, Jastrzebska‐Perfect P, Myers J, Asman P, Ince NF, McKhann G, Viswanathan A, Sheth SA, Khodagholy D, Gelinas JN. Translational Organic Neural Interface Devices at Single Neuron Resolution. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202306. [PMID: 35908811 PMCID: PMC9507374 DOI: 10.1002/advs.202202306] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Recording from the human brain at the spatiotemporal resolution of action potentials provides critical insight into mechanisms of higher cognitive functions and neuropsychiatric disease that is challenging to derive from animal models. Here, organic materials and conformable electronics are employed to create an integrated neural interface device compatible with minimally invasive neurosurgical procedures and geared toward chronic implantation on the surface of the human brain. Data generated with these devices enable identification and characterization of individual, spatially distribute human cortical neurons in the absence of any tissue penetration (n = 229 single units). Putative single-units are effectively clustered, and found to possess features characteristic of pyramidal cells and interneurons, as well as identifiable microcircuit interactions. Human neurons exhibit consistent phase modulation by oscillatory activity and a variety of population coupling responses. The parameters are furthermore established to optimize the yield and quality of single-unit activity from the cortical surface, enhancing the ability to investigate human neural network mechanisms without breaching the tissue interface and increasing the information that can be safely derived from neurophysiological monitoring.
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Affiliation(s)
- Ahnaf Rashik Hassan
- Institute for Genomic MedicineColumbia University Irving Medical CenterNew YorkNY10032USA
- Department of Biomedical EngineeringColumbia UniversityNew YorkNY10027USA
| | - Zifang Zhao
- Department of Electrical EngineeringColumbia UniversityNew YorkNY10027USA
| | - Jose J. Ferrero
- Institute for Genomic MedicineColumbia University Irving Medical CenterNew YorkNY10032USA
| | - Claudia Cea
- Department of Electrical EngineeringColumbia UniversityNew YorkNY10027USA
| | | | - John Myers
- Department of NeurosurgeryBaylor College of MedicineHoustonTX77030USA
| | - Priscella Asman
- Department of Biomedical EngineeringUniversity of HoustonHoustonTX77004USA
| | - Nuri Firat Ince
- Department of Biomedical EngineeringUniversity of HoustonHoustonTX77004USA
| | - Guy McKhann
- Department of NeurosurgeryColumbia University Irving Medical Center and New York Presbyterian HospitalNew YorkNY10032USA
| | | | - Sameer A. Sheth
- Department of NeurosurgeryBaylor College of MedicineHoustonTX77030USA
| | - Dion Khodagholy
- Department of Electrical EngineeringColumbia UniversityNew YorkNY10027USA
| | - Jennifer N. Gelinas
- Institute for Genomic MedicineColumbia University Irving Medical CenterNew YorkNY10032USA
- Department of NeurologyColumbia University Irving Medical Center and New York Presbyterian HospitalNew YorkNY10032USA
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20
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Tringides CM, Mooney DJ. Materials for Implantable Surface Electrode Arrays: Current Status and Future Directions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107207. [PMID: 34716730 DOI: 10.1002/adma.202107207] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/26/2021] [Indexed: 06/13/2023]
Abstract
Surface electrode arrays are mainly fabricated from rigid or elastic materials, and precisely manipulated ductile metal films, which offer limited stretchability. However, the living tissues to which they are applied are nonlinear viscoelastic materials, which can undergo significant mechanical deformation in dynamic biological environments. Further, the same arrays and compositions are often repurposed for vastly different tissues rather than optimizing the materials and mechanical properties of the implant for the target application. By first characterizing the desired biological environment, and then designing a technology for a particular organ, surface electrode arrays may be more conformable, and offer better interfaces to tissues while causing less damage. Here, the various materials used in each component of a surface electrode array are first reviewed, and then electrically active implants in three specific biological systems, the nervous system, the muscular system, and skin, are described. Finally, the fabrication of next-generation surface arrays that overcome current limitations is discussed.
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Affiliation(s)
- Christina M Tringides
- Harvard Program in Biophysics, Harvard University, Cambridge, MA, 02138, USA
- Harvard-MIT Division in Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
| | - David J Mooney
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
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21
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Kiang L, Woodington B, Carnicer-Lombarte A, Malliaras G, Barone DG. Spinal cord bioelectronic interfaces: opportunities in neural recording and clinical challenges. J Neural Eng 2022; 19. [PMID: 35320780 DOI: 10.1088/1741-2552/ac605f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/23/2022] [Indexed: 11/11/2022]
Abstract
Bioelectronic stimulation of the spinal cord has demonstrated significant progress in restoration of motor function in spinal cord injury (SCI). The proximal, uninjured spinal cord presents a viable target for the recording and generation of control signals to drive targeted stimulation. Signals have been directly recorded from the spinal cord in behaving animals and correlated with limb kinematics. Advances in flexible materials, electrode impedance and signal analysis will allow SCR to be used in next-generation neuroprosthetics. In this review, we summarize the technological advances enabling progress in SCR and describe systematically the clinical challenges facing spinal cord bioelectronic interfaces and potential solutions, from device manufacture, surgical implantation to chronic effects of foreign body reaction and stress-strain mismatches between electrodes and neural tissue. Finally, we establish our vision of bi-directional closed-loop spinal cord bioelectronic bypass interfaces that enable the communication of disrupted sensory signals and restoration of motor function in SCI.
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Affiliation(s)
- Lei Kiang
- Orthopaedic Surgery, Singapore General Hospital, Outram Road, Singapore, Singapore, 169608, SINGAPORE
| | - Ben Woodington
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Alejandro Carnicer-Lombarte
- Clinical Neurosciences, University of Cambridge, Bioelectronics Laboratory, Cambridge, CB2 0PY, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - George Malliaras
- University of Cambridge, University of Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Damiano G Barone
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, Cambridgeshire, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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22
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Song H, Luo G, Ji Z, Bo R, Xue Z, Yan D, Zhang F, Bai K, Liu J, Cheng X, Pang W, Shen Z, Zhang Y. Highly-integrated, miniaturized, stretchable electronic systems based on stacked multilayer network materials. SCIENCE ADVANCES 2022; 8:eabm3785. [PMID: 35294232 PMCID: PMC8926335 DOI: 10.1126/sciadv.abm3785] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Elastic stretchability and function density represent two key figures of merits for stretchable inorganic electronics. Various design strategies have been reported to provide both high levels of stretchability and function density, but the function densities are mostly below 80%. While the stacked device layout can overcome this limitation, the soft elastomers used in previous studies could highly restrict the deformation of stretchable interconnects. Here, we introduce stacked multilayer network materials as a general platform to incorporate individual components and stretchable interconnects, without posing any essential constraint to their deformations. Quantitative analyses show a substantial enhancement (e.g., by ~7.5 times) of elastic stretchability of serpentine interconnects as compared to that based on stacked soft elastomers. The proposed strategy allows demonstration of a miniaturized electronic system (11 mm by 10 mm), with a moderate elastic stretchability (~20%) and an unprecedented areal coverage (~110%), which can serve as compass display, somatosensory mouse, and physiological-signal monitor.
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Affiliation(s)
- Honglie Song
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Guoquan Luo
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
- National Key Laboratory of Science and Technology on Advanced Composite in Special Environments, Harbin Institute of Technology, Harbin 150080, P. R. China
| | - Ziyao Ji
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Renheng Bo
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Zhaoguo Xue
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Dongjia Yan
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Fan Zhang
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Ke Bai
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Jianxing Liu
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Xu Cheng
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Wenbo Pang
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Zhangming Shen
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
| | - Yihui Zhang
- AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
- Center for Flexible Electronics Technology, Tsinghua University, Beijing 100084, P. R. China
- Corresponding author.
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Vomero M, Schiavone G. Biomedical Microtechnologies Beyond Scholarly Impact. MICROMACHINES 2021; 12:mi12121471. [PMID: 34945320 PMCID: PMC8709221 DOI: 10.3390/mi12121471] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 11/16/2022]
Abstract
The recent tremendous advances in medical technology at the level of academic research have set high expectations for the clinical outcomes they promise to deliver. To the demise of patient hopes, however, the more disruptive and invasive a new technology is, the bigger the gap is separating the conceptualization of a medical device and its adoption into healthcare systems. When technology breakthroughs are reported in the biomedical scientific literature, news focus typically lies on medical implications rather than engineering progress, as the former are of higher appeal to a general readership. While successful therapy and diagnostics are indeed the ultimate goals, it is of equal importance to expose the engineering thinking needed to achieve such results and, critically, identify the challenges that still lie ahead. Here, we would like to provoke thoughts on the following questions, with particular focus on microfabricated medical devices: should research advancing the maturity and reliability of medical technology benefit from higher accessibility and visibility? How can the scientific community encourage and reward academic work on the overshadowed engineering aspects that will facilitate the evolution of laboratory samples into clinical devices?
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Affiliation(s)
- Maria Vomero
- BioEE Laboratory, Electrical Engineering Department, Columbia University, New York, NY 10027, USA;
| | - Giuseppe Schiavone
- Research Management & Innovation Directorate, King’s College London, Tower Wing, Guy’s Hospital, London SE1 9RT, UK
- Correspondence:
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