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Xu Z, Chen Y, Cao Y, Xue B. Tough Hydrogels with Different Toughening Mechanisms and Applications. Int J Mol Sci 2024; 25:2675. [PMID: 38473922 DOI: 10.3390/ijms25052675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 02/20/2024] [Accepted: 02/24/2024] [Indexed: 03/14/2024] Open
Abstract
Load-bearing biological tissues, such as cartilage and muscles, exhibit several crucial properties, including high elasticity, strength, and recoverability. These characteristics enable these tissues to endure significant mechanical stresses and swiftly recover after deformation, contributing to their exceptional durability and functionality. In contrast, while hydrogels are highly biocompatible and hold promise as synthetic biomaterials, their inherent network structure often limits their ability to simultaneously possess a diverse range of superior mechanical properties. As a result, the applications of hydrogels are significantly constrained. This article delves into the design mechanisms and mechanical properties of various tough hydrogels and investigates their applications in tissue engineering, flexible electronics, and other fields. The objective is to provide insights into the fabrication and application of hydrogels with combined high strength, stretchability, toughness, and fast recovery as well as their future development directions and challenges.
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Affiliation(s)
- Zhengyu Xu
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, China
| | - Yanru Chen
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, China
| | - Yi Cao
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, China
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan 250000, China
| | - Bin Xue
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing 210093, China
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan 250000, China
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2
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Duncan JL, Wang JJ, Glusauskas G, Weagraff GR, Gao Y, Hoeferlin GF, Hunter AH, Hess-Dunning A, Ereifej ES, Capadona JR. In Vivo Characterization of Intracortical Probes with Focused Ion Beam-Etched Nanopatterned Topographies. MICROMACHINES 2024; 15:286. [PMID: 38399014 PMCID: PMC10893395 DOI: 10.3390/mi15020286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/09/2024] [Accepted: 02/14/2024] [Indexed: 02/25/2024]
Abstract
(1) Background: Intracortical microelectrodes (IMEs) are an important part of interfacing with the central nervous system (CNS) and recording neural signals. However, recording electrodes have shown a characteristic steady decline in recording performance owing to chronic neuroinflammation. The topography of implanted devices has been explored to mimic the nanoscale three-dimensional architecture of the extracellular matrix. Our previous work used histology to study the implant sites of non-recording probes and showed that a nanoscale topography at the probe surface mitigated the neuroinflammatory response compared to probes with smooth surfaces. Here, we hypothesized that the improvement in the neuroinflammatory response for probes with nanoscale surface topography would extend to improved recording performance. (2) Methods: A novel design modification was implemented on planar silicon-based neural probes by etching nanopatterned grooves (with a 500 nm pitch) into the probe shank. To assess the hypothesis, two groups of rats were implanted with either nanopatterned (n = 6) or smooth control (n = 6) probes, and their recording performance was evaluated over 4 weeks. Postmortem gene expression analysis was performed to compare the neuroinflammatory response from the two groups. (3) Results: Nanopatterned probes demonstrated an increased impedance and noise floor compared to controls. However, the recording performances of the nanopatterned and smooth probes were similar, with active electrode yields for control probes and nanopatterned probes being approximately 50% and 45%, respectively, by 4 weeks post-implantation. Gene expression analysis showed one gene, Sirt1, differentially expressed out of 152 in the panel. (4) Conclusions: this study provides a foundation for investigating novel nanoscale topographies on neural probes.
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Affiliation(s)
- Jonathan L. Duncan
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH 44106, USA
| | - Jaime J. Wang
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH 44106, USA
| | - Gabriele Glusauskas
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH 44106, USA
| | - Gwendolyn R. Weagraff
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH 44106, USA
| | - Yue Gao
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
| | - George F. Hoeferlin
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH 44106, USA
| | - Allen H. Hunter
- Michigan Center for Materials Characterization, University of Michigan, 500 S. State St, Ann Arbor, MI 48109, USA
| | - Allison Hess-Dunning
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH 44106, USA
| | - Evon S. Ereifej
- Department of Biomedical Engineering, University of Michigan, 500 S. State St, Ann Arbor, MI 48109, USA
- Veterans Affairs Hospital, 2215 Fuller Rd, Ann Arbor, MI 48105, USA
| | - Jeffrey R. Capadona
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH 44106, USA
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3
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Chen T, Lau KSK, Hong SH, Shi HTH, Iwasa SN, Chen JXM, Li T, Morrison T, Kalia SK, Popovic MR, Morshead CM, Naguib HE. Cryogel-based neurostimulation electrodes to activate endogenous neural precursor cells. Acta Biomater 2023; 171:392-405. [PMID: 37683963 DOI: 10.1016/j.actbio.2023.08.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 08/24/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023]
Abstract
The delivery of electrical pulses to the brain via penetrating electrodes, known as brain stimulation, has been recognized as an effective clinical approach for treating neurological disorders. Resident brain neural precursor cells (NPCs) are electrosensitive cells that respond to electrical stimulation by expanding in number, migrating and differentiating which are important characteristics that support neural repair. Here, we report the design of a conductive cryogel brain stimulation electrode specifically developed for NPC activation. The cryogel electrode has a modulus switching mechanism permitting facile penetration and reducing the mechanical mismatch between brain tissue and the penetrating electrode. The cryogel demonstrated good in vivo biocompatibility and reduced the interfacial impedance to deliver the stimulating electric field with lower voltage under charge-balanced current controlled stimulation. An ex vivo assay reveals that electrical stimulation using the cryogel electrodes results in significant expansion in the size of NPC pool. Hence, the cryogel electrodes have the potential to be used for NPC activation to support endogenous neural repair. STATEMENT OF SIGNIFICANCE: The objective of this study is to develop a cryogel-based stimulation electrode as an alternative to traditional electrode materials to be used in regenerative medicine applications for enhancing neural regeneration in brain. The electrode offers benefits such as adaptive modulus for implantation, high charge storage and injection capacities, and modulus matching with brain tissue, allowing for stable delivery of electric field for long-term neuromodulation. The electrochemical properties of cryogel electrodes were characterized in living tissue with an ex vivo set-up, providing a deeper understanding of stimulation capacity in brain environments. The cryogel electrode is biocompatible and enables low voltage, current-controlled stimulation for effective activation of endogenous neural precursor cells, revealing their potential utility in neural stem cell-mediated brain repair.
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Affiliation(s)
- Tianhao Chen
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Kylie Sin Ki Lau
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Sung Hwa Hong
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Hao Tian Harvey Shi
- Department of Mechanical and Materials Engineering, Western University, London, Ontario, Canada
| | - Stephanie N Iwasa
- The KITE Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada; CRANIA, University Health Network and University of Toronto, Toronto, Ontario, Canada
| | - Jia Xi Mary Chen
- Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Terek Li
- Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Taylor Morrison
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Suneil K Kalia
- The KITE Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada; CRANIA, University Health Network and University of Toronto, Toronto, Ontario, Canada; Department of Neurosurgery, University Health Network, University of Toronto, Toronto, Ontario, Canada; Krembil Research Institute, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Milos R Popovic
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada; The KITE Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada; CRANIA, University Health Network and University of Toronto, Toronto, Ontario, Canada
| | - Cindi M Morshead
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada; The KITE Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada; CRANIA, University Health Network and University of Toronto, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
| | - Hani E Naguib
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada; Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario, Canada; Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada.
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4
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Abyzova E, Dogadina E, Rodriguez RD, Petrov I, Kolesnikova Y, Zhou M, Liu C, Sheremet E. Beyond Tissue replacement: The Emerging role of smart implants in healthcare. Mater Today Bio 2023; 22:100784. [PMID: 37731959 PMCID: PMC10507164 DOI: 10.1016/j.mtbio.2023.100784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/22/2023] Open
Abstract
Smart implants are increasingly used to treat various diseases, track patient status, and restore tissue and organ function. These devices support internal organs, actively stimulate nerves, and monitor essential functions. With continuous monitoring or stimulation, patient observation quality and subsequent treatment can be improved. Additionally, using biodegradable and entirely excreted implant materials eliminates the need for surgical removal, providing a patient-friendly solution. In this review, we classify smart implants and discuss the latest prototypes, materials, and technologies employed in their creation. Our focus lies in exploring medical devices beyond replacing an organ or tissue and incorporating new functionality through sensors and electronic circuits. We also examine the advantages, opportunities, and challenges of creating implantable devices that preserve all critical functions. By presenting an in-depth overview of the current state-of-the-art smart implants, we shed light on persistent issues and limitations while discussing potential avenues for future advancements in materials used for these devices.
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Affiliation(s)
- Elena Abyzova
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, Russia, 634050
| | - Elizaveta Dogadina
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, Russia, 634050
- Institute of Orthopaedic & Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK
| | | | - Ilia Petrov
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, Russia, 634050
| | | | - Mo Zhou
- Institute of Orthopaedic & Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK
| | - Chaozong Liu
- Institute of Orthopaedic & Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK
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5
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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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6
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Research Progress on the Flexibility of an Implantable Neural Microelectrode. MICROMACHINES 2022; 13:mi13030386. [PMID: 35334680 PMCID: PMC8954487 DOI: 10.3390/mi13030386] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 12/25/2021] [Accepted: 01/16/2022] [Indexed: 12/22/2022]
Abstract
Neural microelectrode is the important bridge of information exchange between the human body and machines. By recording and transmitting nerve signals with electrodes, people can control the external machines. At the same time, using electrodes to electrically stimulate nerve tissue, people with long-term brain diseases will be safely and reliably treated. Young’s modulus of the traditional rigid electrode probe is not matched well with that of biological tissue, and tissue immune rejection is easy to generate, resulting in the electrode not being able to achieve long-term safety and reliable working. In recent years, the choice of flexible materials and design of electrode structures can achieve modulus matching between electrode and biological tissue, and tissue damage is decreased. This review discusses nerve microelectrodes based on flexible electrode materials and substrate materials. Simultaneously, different structural designs of neural microelectrodes are reviewed. However, flexible electrode probes are difficult to implant into the brain. Only with the aid of certain auxiliary devices, can the implant be safe and reliable. The implantation method of the nerve microelectrode is also reviewed.
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7
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Schander A, Gancz JM, Tintelott M, Lang W. Towards Long-Term Stable Polyimide-Based Flexible Electrical Insulation for Chronically Implanted Neural Electrodes. MICROMACHINES 2021; 12:mi12111279. [PMID: 34832690 PMCID: PMC8619170 DOI: 10.3390/mi12111279] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 01/03/2023]
Abstract
For chronic applications of flexible neural implants, e.g., intracortical probes, the flexible substrate material has to encapsulate the electrical conductors with a long-term stability against the saline environment of the neural tissue. The biocompatible polymer polyimide is often used for this purpose. Due to its chemical inertness, the adhesion between two polyimide layers is, however, a challenge, which can lead to delamination and, finally, to short circuits. The state-of-the-art method to improve the adhesion strength is activating the polyimide surface using oxygen reactive ion etching (O2 RIE). However, the influence of the process variations (etching time, bias power) on the long-term stability is still unclear. Therefore, we establish a test method, where the aging of a gold interdigital structure embedded in two polyimide layers and immersed in saline solution is accelerated using an elevated temperature, mechanical stress and an electrical field. A continuous measurement of a leakage current is used to define the failure state. The results show that the variation of the O2 RIE plasma process has a significant effect on the long-term stability of the test samples. Comparing the two different plasma treatments 0.5 min at 25 W and 1 min at 50 W, the long-term stability could be increased from 20.9 ± 19.1 days to 44.9 ± 18.9 days. This corresponds to more than a doubled lifetime. An ideal solution for the delamination problem is still not available; however, the study shows that the fine-tuning of the fabrication processes can improve the long-term stability of chronically implanted neural electrodes.
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Affiliation(s)
- Andreas Schander
- Institute for Microsensors, -Actuators and -Systems (IMSAS), University of Bremen, 28359 Bremen, Germany; (J.M.G.); (M.T.); (W.L.)
- Correspondence: ; Tel.: +49-421-218-62590
| | - Julia M. Gancz
- Institute for Microsensors, -Actuators and -Systems (IMSAS), University of Bremen, 28359 Bremen, Germany; (J.M.G.); (M.T.); (W.L.)
| | - Marcel Tintelott
- Institute for Microsensors, -Actuators and -Systems (IMSAS), University of Bremen, 28359 Bremen, Germany; (J.M.G.); (M.T.); (W.L.)
- Institute of Materials in Electrical Engineering 1, RWTH Aachen University, 52074 Aachen, Germany
| | - Walter Lang
- Institute for Microsensors, -Actuators and -Systems (IMSAS), University of Bremen, 28359 Bremen, Germany; (J.M.G.); (M.T.); (W.L.)
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8
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Garcia-Sandoval A, Guerrero E, Hosseini SM, Rocha-Flores PE, Rihani R, Black BJ, Pal A, Carmel JB, Pancrazio JJ, Voit WE. Stable softening bioelectronics: A paradigm for chronically viable ester-free neural interfaces such as spinal cord stimulation implants. Biomaterials 2021; 277:121073. [PMID: 34419732 PMCID: PMC8642083 DOI: 10.1016/j.biomaterials.2021.121073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 07/25/2021] [Accepted: 08/15/2021] [Indexed: 01/01/2023]
Abstract
Polymer toughness is preserved at chronic timepoints in a new class of modulus-changing bioelectronics, which hold promise for commercial chronic implant components such as spinal cord stimulation leads. The underlying ester-free chemical network of the polymer substrate enables device rigidity during implantation, soft, compliant, conforming structures during acute phases in vivo, and gradual stabilization of materials properties chronically, maintaining materials toughness as device stiffness changes. In the past, bioelectronics device designs generally avoided modulus-changing and materials due to the difficulty in demonstrating consistent, predictable performance over time in the body. Here, the acute, and chronic mechanical and chemical properties of a new class of ester-free bioelectronic substrates are described and characterized via accelerated aging at elevated temperatures, with an assessment of their underlying cytotoxicity. Furthermore, spinal cord stimulation leads consisting of photolithographically-defined gold traces and titanium nitride (TiN) electrodes are fabricated on ester-free polymer substrates. Electrochemical properties of the fabricated devices are determined in vitro before implantation in the cervical spinal cord of rat models and subsequent quantification of device stimulation capabilities. Preliminary in vivo evidence demonstrates that this new generation of ester-free, softening bioelectronics holds promise to realize stable, scalable, chronically viable components for bioelectronic medicines of the future.
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Affiliation(s)
- Aldo Garcia-Sandoval
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA.
| | - Edgar Guerrero
- Department of Materials Science and Engineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Seyed Mahmoud Hosseini
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Pedro E Rocha-Flores
- Department of Materials Science and Engineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Rashed Rihani
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Bryan J Black
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Ajay Pal
- Department of Neurology and Orthopedics, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
| | - Jason B Carmel
- Department of Neurology and Orthopedics, Columbia University, 650 W. 168th St, New York, NY, 10032, USA
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Walter E Voit
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA; Department of Materials Science and Engineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA; Department of Mechanical Engineering, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA; Center for Engineering Innovation, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA.
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9
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Gori M, Vadalà G, Giannitelli SM, Denaro V, Di Pino G. Biomedical and Tissue Engineering Strategies to Control Foreign Body Reaction to Invasive Neural Electrodes. Front Bioeng Biotechnol 2021; 9:659033. [PMID: 34113605 PMCID: PMC8185207 DOI: 10.3389/fbioe.2021.659033] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/27/2021] [Indexed: 12/21/2022] Open
Abstract
Neural-interfaced prostheses aim to restore sensorimotor limb functions in amputees. They rely on bidirectional neural interfaces, which represent the communication bridge between nervous system and neuroprosthetic device by controlling its movements and evoking sensory feedback. Compared to extraneural electrodes (i.e., epineural and perineural implants), intraneural electrodes, implanted within peripheral nerves, have higher selectivity and specificity of neural signal recording and nerve stimulation. However, being implanted in the nerve, their main limitation is represented by the significant inflammatory response that the body mounts around the probe, known as Foreign Body Reaction (FBR), which may hinder their rapid clinical translation. Furthermore, the mechanical mismatch between the consistency of the device and the surrounding neural tissue may contribute to exacerbate the inflammatory state. The FBR is a non-specific reaction of the host immune system to a foreign material. It is characterized by an early inflammatory phase eventually leading to the formation of a fibrotic capsule around intraneural interfaces, which increases the electrical impedance over time and reduces the chronic interface biocompatibility and functionality. Thus, the future in the reduction and control of the FBR relies on innovative biomedical strategies for the fabrication of next-generation neural interfaces, such as the development of more suitable designs of the device with smaller size, appropriate stiffness and novel conductive and biomimetic coatings for improving their long-term stability and performance. Here, we present and critically discuss the latest biomedical approaches from material chemistry and tissue engineering for controlling and mitigating the FBR in chronic neural implants.
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Affiliation(s)
- Manuele Gori
- Laboratory for Regenerative Orthopaedics, Department of Orthopaedic Surgery and Traumatology, Università Campus Bio-Medico di Roma, Rome, Italy
- Institute of Biochemistry and Cell Biology (IBBC) - National Research Council (CNR), Rome, Italy
| | - Gianluca Vadalà
- Laboratory for Regenerative Orthopaedics, Department of Orthopaedic Surgery and Traumatology, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Sara Maria Giannitelli
- Laboratory of Tissue Engineering, Department of Engineering, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Vincenzo Denaro
- Laboratory for Regenerative Orthopaedics, Department of Orthopaedic Surgery and Traumatology, Università Campus Bio-Medico di Roma, Rome, Italy
| | - Giovanni Di Pino
- NeXT: Neurophysiology and Neuroengineering of Human-Technology Interaction Research Unit, Università Campus Bio-Medico di Roma, Rome, Italy
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10
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Apollo NV, Murphy B, Prezelski K, Driscoll N, Richardson AG, Lucas TH, Vitale F. Gels, jets, mosquitoes, and magnets: a review of implantation strategies for soft neural probes. J Neural Eng 2020; 17:041002. [PMID: 32759476 PMCID: PMC8152109 DOI: 10.1088/1741-2552/abacd7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Implantable neuroelectronic interfaces have enabled breakthrough advances in the clinical diagnosis and treatment of neurological disorders, as well as in fundamental studies of brain function, behavior, and disease. Intracranial electroencephalography (EEG) mapping with stereo-EEG (sEEG) depth electrodes is routinely adopted for precise epilepsy diagnostics and surgical treatment, while deep brain stimulation has become the standard of care for managing movement disorders. Intracortical microelectrode arrays for high-fidelity recordings of neural spiking activity have led to impressive demonstrations of the power of brain-machine interfaces for motor and sensory functional recovery. Yet, despite the rapid pace of technology development, the issue of establishing a safe, long-term, stable, and functional interface between neuroelectronic devices and the host brain tissue still remains largely unresolved. A body of work spanning at least the last 15 years suggests that safe, chronic integration between invasive electrodes and the brain requires a close match between the mechanical properties of man-made components and the neural tissue. In other words, the next generation of invasive electrodes should be soft and compliant, without sacrificing biological and chemical stability. Soft neuroelectronic interfaces, however, pose a new and significant surgical challenge: bending and buckling during implantation that can preclude accurate and safe device placement. In this topical review, we describe the next generation of soft electrodes and the surgical implantation methods for safe and precise insertion into brain structures. We provide an overview of the most recent innovations in the field of insertion strategies for flexible neural electrodes such as dissolvable or biodegradable carriers, microactuators, biologically-inspired support structures, and electromagnetic drives. In our analysis, we also highlight approaches developed in different fields, such as robotic surgery, which could be potentially adapted and translated to the insertion of flexible neural probes.
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Affiliation(s)
- Nicholas V Apollo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
| | - Brendan Murphy
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
| | - Kayla Prezelski
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
| | - Nicolette Driscoll
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
| | - Andrew G Richardson
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
| | - Timothy H Lucas
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
| | - Flavia Vitale
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Physical Medicine & Rehabilitation, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, United States of America
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11
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Xiao R, Huang WM. Heating/Solvent Responsive Shape-Memory Polymers for Implant Biomedical Devices in Minimally Invasive Surgery: Current Status and Challenge. Macromol Biosci 2020; 20:e2000108. [PMID: 32567193 DOI: 10.1002/mabi.202000108] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/03/2020] [Indexed: 12/16/2022]
Abstract
This review is about the fundamentals and practical issues in applying both heating and solvent responsive shape memory polymers (SMPs) for implant biomedical devices via minimally invasive surgery. After revealing the general requirements in the design of biomedical devices based on SMPs and the fundamentals for the shape-memory effect in SMPs, the underlying mechanisms, characterization methods, and several representative biomedical applications, including vascular stents, tissue scaffolds, occlusion devices, drug delivery systems, and the current R&D status of them, are discussed. The new opportunities arising from emerging technologies, such as 3D printing, and new materials, such as vitrimer, are also highlighted. Finally, the major challenge that limits the practical clinical applications of SMPs at present is addressed.
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Affiliation(s)
- Rui Xiao
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027, China
| | - Wei Min Huang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
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12
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Won SM, Song E, Reeder JT, Rogers JA. Emerging Modalities and Implantable Technologies for Neuromodulation. Cell 2020; 181:115-135. [DOI: 10.1016/j.cell.2020.02.054] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/23/2020] [Accepted: 02/25/2020] [Indexed: 02/08/2023]
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13
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Shoffstall AJ, Capadona JR. Bioelectronic Neural Implants. Biomater Sci 2020. [DOI: 10.1016/b978-0-12-816137-1.00073-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Beygi M, Bentley JT, Frewin CL, Kuliasha CA, Takshi A, Bernardin EK, La Via F, Saddow SE. Fabrication of a Monolithic Implantable Neural Interface from Cubic Silicon Carbide. MICROMACHINES 2019; 10:mi10070430. [PMID: 31261887 PMCID: PMC6680876 DOI: 10.3390/mi10070430] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/18/2019] [Accepted: 06/26/2019] [Indexed: 02/07/2023]
Abstract
One of the main issues with micron-sized intracortical neural interfaces (INIs) is their long-term reliability, with one major factor stemming from the material failure caused by the heterogeneous integration of multiple materials used to realize the implant. Single crystalline cubic silicon carbide (3C-SiC) is a semiconductor material that has been long recognized for its mechanical robustness and chemical inertness. It has the benefit of demonstrated biocompatibility, which makes it a promising candidate for chronically-stable, implantable INIs. Here, we report on the fabrication and initial electrochemical characterization of a nearly monolithic, Michigan-style 3C-SiC microelectrode array (MEA) probe. The probe consists of a single 5 mm-long shank with 16 electrode sites. An ~8 µm-thick p-type 3C-SiC epilayer was grown on a silicon-on-insulator (SOI) wafer, which was followed by a ~2 µm-thick epilayer of heavily n-type (n+) 3C-SiC in order to form conductive traces and the electrode sites. Diodes formed between the p and n+ layers provided substrate isolation between the channels. A thin layer of amorphous silicon carbide (a-SiC) was deposited via plasma-enhanced chemical vapor deposition (PECVD) to insulate the surface of the probe from the external environment. Forming the probes on a SOI wafer supported the ease of probe removal from the handle wafer by simple immersion in HF, thus aiding in the manufacturability of the probes. Free-standing probes and planar single-ended test microelectrodes were fabricated from the same 3C-SiC epiwafers. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed on test microelectrodes with an area of 491 µm2 in phosphate buffered saline (PBS) solution. The measurements showed an impedance magnitude of 165 kΩ ± 14.7 kΩ (mean ± standard deviation) at 1 kHz, anodic charge storage capacity (CSC) of 15.4 ± 1.46 mC/cm2, and a cathodic CSC of 15.2 ± 1.03 mC/cm2. Current-voltage tests were conducted to characterize the p-n diode, n-p-n junction isolation, and leakage currents. The turn-on voltage was determined to be on the order of ~1.4 V and the leakage current was less than 8 μArms. This all-SiC neural probe realizes nearly monolithic integration of device components to provide a likely neurocompatible INI that should mitigate long-term reliability issues associated with chronic implantation.
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Affiliation(s)
- Mohammad Beygi
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA
| | - John T Bentley
- Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA
| | | | - Cary A Kuliasha
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Arash Takshi
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA
| | - Evans K Bernardin
- Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA
| | - Francesco La Via
- CNR Institute for Microelectronics and Microsystems, Catania, Sicily 95121, Italy
| | - Stephen E Saddow
- Department of Electrical Engineering, University of South Florida, Tampa, FL 33620, USA.
- Department of Medical Engineering, University of South Florida, Tampa, FL 33620, USA.
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15
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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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16
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Ecker M, Joshi-Imre A, Modi R, Frewin CL, Garcia-Sandoval A, Maeng J, Gutierrez-Heredia G, Pancrazio JJ, Voit WE. From softening polymers to multimaterial based bioelectronic devices. ACTA ACUST UNITED AC 2018. [DOI: 10.1088/2399-7532/aaed58] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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17
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Deku F, Frewin CL, Stiller A, Cohen Y, Aqeel S, Joshi-Imre A, Black B, Gardner TJ, Pancrazio JJ, Cogan SF. Amorphous Silicon Carbide Platform for Next Generation Penetrating Neural Interface Designs. MICROMACHINES 2018; 9:E480. [PMID: 30424413 PMCID: PMC6215182 DOI: 10.3390/mi9100480] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/09/2018] [Accepted: 09/17/2018] [Indexed: 11/16/2022]
Abstract
Microelectrode arrays that consistently and reliably record and stimulate neural activity under conditions of chronic implantation have so far eluded the neural interface community due to failures attributed to both biotic and abiotic mechanisms. Arrays with transverse dimensions of 10 µm or below are thought to minimize the inflammatory response; however, the reduction of implant thickness also decreases buckling thresholds for materials with low Young's modulus. While these issues have been overcome using stiffer, thicker materials as transport shuttles during implantation, the acute damage from the use of shuttles may generate many other biotic complications. Amorphous silicon carbide (a-SiC) provides excellent electrical insulation and a large Young's modulus, allowing the fabrication of ultrasmall arrays with increased resistance to buckling. Prototype a-SiC intracortical implants were fabricated containing 8 - 16 single shanks which had critical thicknesses of either 4 µm or 6 µm. The 6 µm thick a-SiC shanks could penetrate rat cortex without an insertion aid. Single unit recordings from SIROF-coated arrays implanted without any structural support are presented. This work demonstrates that a-SiC can provide an excellent mechanical platform for devices that penetrate cortical tissue while maintaining a critical thickness less than 10 µm.
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Affiliation(s)
- Felix Deku
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Christopher L Frewin
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Allison Stiller
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Yarden Cohen
- Department of Biology and Biomedical Engineering, Boston University, Boston, MA 02215, USA.
| | - Saher Aqeel
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Alexandra Joshi-Imre
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Bryan Black
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Timothy J Gardner
- Department of Biology and Biomedical Engineering, Boston University, Boston, MA 02215, USA.
| | - Joseph J Pancrazio
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - Stuart F Cogan
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
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18
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Won SM, Song E, Zhao J, Li J, Rivnay J, Rogers JA. Recent Advances in Materials, Devices, and Systems for Neural Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1800534. [PMID: 29855089 DOI: 10.1002/adma.201800534] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 02/28/2018] [Indexed: 06/08/2023]
Abstract
Technologies capable of establishing intimate, long-lived optical/electrical interfaces to neural systems will play critical roles in neuroscience research and in the development of nonpharmacological treatments for neurological disorders. The development of high-density interfaces to 3D populations of neurons across entire tissue systems in living animals, including human subjects, represents a grand challenge for the field, where advanced biocompatible materials and engineered structures for electrodes and light emitters will be essential. This review summarizes recent progress in these directions, with an emphasis on the most promising demonstrated concepts, materials, devices, and systems. The article begins with an overview of electrode materials with enhanced electrical and/or mechanical performance, in forms ranging from planar films, to micro/nanostructured surfaces, to 3D porous frameworks and soft composites. Subsequent sections highlight integration with active materials and components for multiplexed addressing, local amplification, wireless data transmission, and power harvesting, with multimodal operation in soft, shape-conformal systems. These advances establish the foundations for scalable architectures in optical/electrical neural interfaces of the future, where a blurring of the lines between biotic and abiotic systems will catalyze profound progress in neuroscience research and in human health/well-being.
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Affiliation(s)
- Sang Min Won
- Department of Electrical and Computer Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Urbana, IL, 61801, USA
| | - Enming Song
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Northwestern University, Evanston, IL, 60208, USA
| | - Jianing Zhao
- Department of Mechanical Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Urbana, IL, 61801, USA
| | - Jinghua Li
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana Champaign, Northwestern University, Evanston, IL, 60208, USA
| | - Jonathan Rivnay
- Department of Biomedical Engineering, Simpson Querrey Institute for Nanobiotechnology, Northwestern University, Evanston, IL, 60208, USA
| | - John A Rogers
- Center for Bio-Integrated Electronics, Department of Materials Science and Engineering, Biomedical Engineering, Chemistry, Mechanical Engineering, Electrical Engineering and Computer Science, and Neurological Surgery, Simpson Querrey Institute for Nano/biotechnology, McCormick School of Engineering and Feinberg School of Medicine, Northwestern University, Evanston, IL, 60208, USA
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19
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Garcia-Sandoval A, Pal A, Mishra AM, Sherman S, Parikh AR, Joshi-Imre A, Arreaga-Salas D, Gutierrez-Heredia G, Duran-Martinez AC, Nathan J, Hosseini SM, Carmel JB, Voit W. Chronic softening spinal cord stimulation arrays. J Neural Eng 2018; 15:045002. [PMID: 29569573 DOI: 10.1088/1741-2552/aab90d] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE We sought to develop a cervical spinal cord stimulator for the rat that is durable, stable, and does not perturb the underlying spinal cord. APPROACH We created a softening spinal cord stimulation (SCS) array made from shape memory polymer (SMP)-based flexible electronics. We developed a new photolithographic process to pattern high surface area titanium nitride (TiN) electrodes onto gold (Au) interconnects. The thiol-ene acrylate polymers are stiff at room temperature and soften following implantation into the body. Durability was measured by the duration the devices produced effective stimulation and by accelerated aging in vitro. Stability was measured by the threshold to provoke an electromyogram (EMG) muscle response and by measuring impedance using electrochemical impedance spectroscopy (EIS). In addition, spinal cord modulation of motor cortex potentials was measured. The spinal column and implanted arrays were imaged with MRI ex vivo, and histology for astrogliosis and immune reaction was performed. MAIN RESULTS For durability, the design of the arrays was modified over three generations to create an array that demonstrated activity up to 29 weeks. SCS arrays showed no significant degradation over a simulated 29 week period of accelerated aging. For stability, the threshold for provoking an EMG rose in the first few weeks and then remained stable out to 16 weeks; the impedance showed a similar rise early with stability thereafter. Spinal cord stimulation strongly enhanced motor cortex potentials throughout. Upon explantation, device performance returned to pre-implant levels, indicating that biotic rather than abiotic processes were the cause of changing metrics. MRI and histology showed that softening SCS produced less tissue deformation than Parylene-C arrays. There was no significant astrogliosis or immune reaction to either type of array. SIGNIFICANCE Softening SCS arrays meet the needs for research-grade devices in rats and could be developed into human devices in the future.
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Affiliation(s)
- Aldo Garcia-Sandoval
- Department of Mechanical Engineering, The University of Texas at Dallas, Richardson, TX 75080, United States of America
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20
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Lecomte A, Descamps E, Bergaud C. A review on mechanical considerations for chronically-implanted neural probes. J Neural Eng 2018; 15:031001. [DOI: 10.1088/1741-2552/aa8b4f] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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21
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A Mosquito Inspired Strategy to Implant Microprobes into the Brain. Sci Rep 2018; 8:122. [PMID: 29317748 PMCID: PMC5760625 DOI: 10.1038/s41598-017-18522-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 12/13/2017] [Indexed: 02/05/2023] Open
Abstract
Mosquitos are among the deadliest insects on the planet due to their ability to transmit diseases like malaria through their bite. In order to bite, a mosquito must insert a set of micro-sized needles through the skin to reach vascular structures. The mosquito uses a combination of mechanisms including an insertion guide to enable it to bite and feed off of larger animals. Here, we report on a biomimetic strategy inspired by the mosquito insertion guide to enable the implantation of intracortical microelectrodes into the brain. Next generation microelectrode designs leveraging ultra-small dimensions and/or flexible materials offer the promise of increased performance, but present difficulties in reliable implantation. With the biomimetic guide in place, the rate of successful microprobe insertion increased from 37.5% to 100% due to the rise in the critical buckling force of the microprobes by 3.8-fold. The prototype guides presented here provide a reproducible method to augment the insertion of small, flexible devices into the brain. In the future, similar approaches may be considered and applied to the insertion of other difficult to implant medical devices.
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22
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Prospects for a Robust Cortical Recording Interface. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00028-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Somann JP, Albors GO, Neihouser KV, Lu KH, Liu Z, Ward MP, Durkes A, Robinson JP, Powley TL, Irazoqui PP. Chronic cuffing of cervical vagus nerve inhibits efferent fiber integrity in rat model. J Neural Eng 2017; 15:036018. [PMID: 29219123 DOI: 10.1088/1741-2552/aaa039] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Numerous studies of vagal nerve stimulation (VNS) have been published showing it to be a potential treatment for chronic inflammation and other related diseases and disorders. Studies in recent years have shown that electrical stimulation of the vagal efferent fibers can artificially modulate cytokine levels and reduce systematic inflammation. Most VNS research in the treatment of inflammation have been acute studies on rodent subjects. Our study tested VNS on freely moving animals by stimulating and recording from the cervical vagus with nerve cuff electrodes over an extended period of time. APPROACH We used methods of electrical stimulation, retrograde tracing (using Fluorogold) and post necropsy histological analysis of nerve tissue, flow cytometry to measure plasma cytokine levels, and MRI scanning of gastric emptying. This novel combination of methods allowed examination of physiological aspects of VNS previously unexplored. MAIN RESULTS Through our study of 53 rat subjects, we found that chronically cuffing the left cervical vagus nerve suppressed efferent Fluorogold transport in 43 of 44 animals (36 showed complete suppression). Measured cytokine levels and gastric emptying rates concurrently showed nominal differences between chronically cuffed rats and those tested with similar acute methods. Meanwhile, results of electrophysiological and histological tests of the cuffed nerves revealed them to be otherwise healthy, consistent with previous literature. SIGNIFICANCE We hypothesize that due to these unforeseen and unexplored physiological consequences of the chronically cuffed vagus nerve in a rat, that inflammatory modulation and other vagal effects by VNS may become unreliable in chronic studies. Given our findings, we submit that it would benefit the VNS community to re-examine methods used in previous literature to verify the efficacy of the rat model for chronic VNS studies.
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Affiliation(s)
- Jesse P Somann
- Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, United States of America. Center for Implantable Devices (CID), Purdue University, West Lafayette, Indiana, United States of America
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24
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Woeppel K, Yang Q, Cui XT. Recent Advances in Neural Electrode-Tissue Interfaces. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2017; 4:21-31. [PMID: 29423457 PMCID: PMC5798641 DOI: 10.1016/j.cobme.2017.09.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Neurotechnology is facing an exponential growth in the recent decades. Neural electrode-tissue interface research has been well recognized as an instrumental component of neurotechnology development. While satisfactory long-term performance was demonstrated in some applications, such as cochlear implants and deep brain stimulators, more advanced neural electrode devices requiring higher resolution for single unit recording or microstimulation still face significant challenges in reliability and longevity. In this article, we review the most recent findings that contribute to our current understanding of the sources of poor reliability and longevity in neural recording or stimulation, including the material failure, biological tissue response and the interplay between the two. The newly developed characterization tools are introduced from electrophysiology models, molecular and biochemical analysis, material characterization to live imaging. The effective strategies that have been applied to improve the interface are also highlighted. Finally, we discuss the challenges and opportunities in improving the interface and achieving seamless integration between the implanted electrodes and neural tissue both anatomically and functionally.
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Affiliation(s)
- Kevin Woeppel
- Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
| | - Qianru Yang
- Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
| | - Xinyan Tracy Cui
- Bioengineering, University of Pittsburgh
- Center for the Neural Basis of Cognition, University of Pittsburgh
- McGowan Institute for Regenerative Medicine, University of Pittsburgh
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25
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Microelectrode implantation in motor cortex causes fine motor deficit: Implications on potential considerations to Brain Computer Interfacing and Human Augmentation. Sci Rep 2017; 7:15254. [PMID: 29127346 PMCID: PMC5681545 DOI: 10.1038/s41598-017-15623-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 10/25/2017] [Indexed: 12/22/2022] Open
Abstract
Intracortical microelectrodes have shown great success in enabling locked-in patients to interact with computers, robotic limbs, and their own electrically driven limbs. The recent advances have inspired world-wide enthusiasm resulting in billions of dollars invested in federal and industrial sponsorships to understanding the brain for rehabilitative applications. Additionally, private philanthropists have also demonstrated excitement in the field by investing in the use of brain interfacing technologies as a means to human augmentation. While the promise of incredible technologies is real, caution must be taken as implications regarding optimal performance and unforeseen side effects following device implantation into the brain are not fully characterized. The current study is aimed to quantify any motor deficit caused by microelectrode implantation in the motor cortex of healthy rats compared to non-implanted controls. Following electrode insertion, rats were tested on an open-field grid test to study gross motor function and a ladder test to study fine motor function. It was discovered that rats with chronically indwelling intracortical microelectrodes exhibited up to an incredible 527% increase in time to complete the fine motor task. This initial study defines the need for further and more robust behavioral testing of potential unintentional harm caused by microelectrode implantation.
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26
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Do DH, Ecker M, Voit WE. Characterization of a Thiol-Ene/Acrylate-Based Polymer for Neuroprosthetic Implants. ACS OMEGA 2017; 2:4604-4611. [PMID: 30023725 PMCID: PMC6044618 DOI: 10.1021/acsomega.7b00834] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 08/04/2017] [Indexed: 05/18/2023]
Abstract
Thiol-ene/acrylate shape-memory polymers can be used as base substrates for neural electrodes to treat neurological dysfunction. Neural electrodes are implanted into the body to alter or record impulse conduction. This study characterizes thiol-ene/acrylate polymers to determine which synthesis methods constitute an ideal substrate for neural implants. To achieve a desired Tg between 50 and 56.5 °C, curing conditions, polymer thickness, monomer ratios, and water uptake were all examined and controlled for. Characterization with dynamic mechanical analysis and thermal gravimetric analysis reveals that thin, thiol-ene/acrylate polymers composed of at least 50 mol % acrylate content and cured for at least 1 h at 365 nm are promising as substrates for neural electrodes.
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Affiliation(s)
- Dang-Huy Do
- Department
of Biological Sciences and Department of Materials Science
and Engineering, The University of Texas
at Dallas, 800 W Campbell Road, Richardson, Texas 75080, United
States
| | - Melanie Ecker
- Department
of Biological Sciences and Department of Materials Science
and Engineering, The University of Texas
at Dallas, 800 W Campbell Road, Richardson, Texas 75080, United
States
| | - Walter E. Voit
- Department
of Biological Sciences and Department of Materials Science
and Engineering, The University of Texas
at Dallas, 800 W Campbell Road, Richardson, Texas 75080, United
States
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27
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Bensmaia SJ. Biological and bionic hands: natural neural coding and artificial perception. Philos Trans R Soc Lond B Biol Sci 2016; 370:20140209. [PMID: 26240424 PMCID: PMC4528821 DOI: 10.1098/rstb.2014.0209] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The first decade and a half of the twenty-first century brought about two major innovations in neuroprosthetics: the development of anthropomorphic robotic limbs that replicate much of the function of a native human arm and the refinement of algorithms that decode intended movements from brain activity. However, skilled manipulation of objects requires somatosensory feedback, for which vision is a poor substitute. For upper-limb neuroprostheses to be clinically viable, they must therefore provide for the restoration of touch and proprioception. In this review, I discuss efforts to elicit meaningful tactile sensations through stimulation of neurons in somatosensory cortex. I focus on biomimetic approaches to sensory restoration, which leverage our current understanding about how information about grasped objects is encoded in the brain of intact individuals. I argue that not only can sensory neuroscience inform the development of sensory neuroprostheses, but also that the converse is true: stimulating the brain offers an exceptional opportunity to causally interrogate neural circuits and test hypotheses about natural neural coding.
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Affiliation(s)
- Sliman J Bensmaia
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
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Implantable neurotechnologies: a review of micro- and nanoelectrodes for neural recording. Med Biol Eng Comput 2016; 54:23-44. [PMID: 26753777 DOI: 10.1007/s11517-015-1430-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 12/10/2015] [Indexed: 12/22/2022]
Abstract
Electrodes serve as the first critical interface to the biological organ system. In neuroprosthetic applications, for example, electrodes interface to the tissue for either signal recording or tissue stimulation. In this review, we consider electrodes for recording neural activity. Recording electrodes serve as wiretaps into the neural tissues, providing readouts of electrical activity. These signals give us valuable insights into the organization and functioning of the nervous system. The recording interfaces have also shown promise in aiding treatment of motor and sensory disabilities caused by neurological disorders. Recent advances in fabrication technology have generated wide interest in creating tiny, high-density electrode interfaces for neural tissues. An ideal electrode should be small enough and be able to achieve reliable and conformal integration with the structures of the nervous system. As a result, the existing electrode designs are being shrunk and packed to form small form factor interfaces to tissue. Here, an overview of the historic and state-of-the-art electrode technologies for recording neural activity is presented first with a focus on their development road map. The fact that the dimensions of recording electrode sites are being scaled down from micron to submicron scale to enable dense interfaces is appreciated. The current trends in recording electrode technologies are then reviewed. Current and future considerations in electrode design, including the use of inorganic nanostructures and biologically inspired or biocomapatible materials are discussed, along with an overview of the applications of flexible materials and transistor transduction schemes. Finally, we detail the major technical challenges facing chronic use of reliable recording electrode technology.
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Johnson BN, Lancaster KZ, Zhen G, He J, Gupta MK, Kong YL, Engel EA, Krick KD, Ju A, Meng F, Enquist LW, Jia X, McAlpine MC. 3D Printed Anatomical Nerve Regeneration Pathways. ADVANCED FUNCTIONAL MATERIALS 2015; 25:6205-6217. [PMID: 26924958 PMCID: PMC4765385 DOI: 10.1002/adfm.201501760] [Citation(s) in RCA: 170] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
An imaging-coupled 3D printing methodology for the design, optimization, and fabrication of a customized nerve repair technology for complex injuries is presented. The custom scaffolds are deterministically fabricated via a microextrusion printing principle which enables the simultaneous incorporation of anatomical geometries, biomimetic physical cues, and spatially controlled biochemical gradients in a one-pot 3D manufacturing approach.
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Affiliation(s)
- Blake N. Johnson
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States, Department of Industrial and Systems Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Karen Z. Lancaster
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Gehua Zhen
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Junyun He
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Maneesh K. Gupta
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Yong Lin Kong
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Esteban A. Engel
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Kellin D. Krick
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States
| | - Alex Ju
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Fanben Meng
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Lynn W. Enquist
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey 08544, United States
| | - Xiaofeng Jia
- Department of Neurosurgery, Orthopedics, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States, Department of Biomedical Engineering, Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Michael C. McAlpine
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States, Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Huang WC, Lai HY, Kuo LW, Liao CH, Chang PH, Liu TC, Chen SY, Chen YY. Multifunctional 3D Patternable Drug-Embedded Nanocarrier-Based Interfaces to Enhance Signal Recording and Reduce Neuron Degeneration in Neural Implantation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:4186-4193. [PMID: 26074252 DOI: 10.1002/adma.201500136] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Revised: 05/12/2015] [Indexed: 06/04/2023]
Affiliation(s)
- Wei-Chen Huang
- Department of Materials Science and Engineering, National Chiao Tung University, No. 1001, Ta-Hsueh Rd., Hsinchu, 30010, Taiwan
| | - Hsin-Yi Lai
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, No. 268, Kaixuan Road, Hangzhou City, Zhejiang Province, 310029, China
| | - Li-Wei Kuo
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, No. Keyan Road, Miaoli, 35053, Taiwan
| | - Chia-Hsin Liao
- Department of Medical Research, Buddhist Tzu Chi General Hospital, No. 707, Sec. 3, Chung-Yang Rd., Hualien, 97002, Taiwan
| | - Po-Hsieh Chang
- Department of Materials Science and Engineering, National Chiao Tung University, No. 1001, Ta-Hsueh Rd., Hsinchu, 30010, Taiwan
| | - Ta-Chung Liu
- Department of Materials Science and Engineering, National Chiao Tung University, No. 1001, Ta-Hsueh Rd., Hsinchu, 30010, Taiwan
| | - San-Yuan Chen
- Department of Materials Science and Engineering, National Chiao Tung University, No. 1001, Ta-Hsueh Rd., Hsinchu, 30010, Taiwan
| | - You-Yin Chen
- Department of Biomedical Engineering, National Yang Ming University, No. 155, Sec. 2, Linong St., Taipei, 11221, Taiwan
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31
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Uppalapati S, Kong N, Norberg O, Ramström O, Yan M. Ionization of covalent immobilized poly(4-vinylphenol) monolayers measured by ellipsometry, QCM and SPR. APPLIED SURFACE SCIENCE 2015; 343:166-171. [PMID: 26097271 PMCID: PMC4469237 DOI: 10.1016/j.apsusc.2015.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Covalently immobilized poly(4-vinylphenol) (PVP) monolayer films were fabricated by spin coating PVP on perfluorophenyl azide (PFPA)-functionalized surface followed by UV irradiation. The pH-responsive behavior of these PVP ultrathin films was evaluated by ellipsometry, quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). By monitoring the responses of these films to pH in situ, the ionization constant of the monolayer thin films was obtained. The apparent pKa value of these covalently immobilized PVP monolayers, 13.4 by SPR, was 3 units higher than that of the free polymer in aqueous solution.
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Affiliation(s)
- Suji Uppalapati
- Department of Chemistry, University of Massachusetts Lowell, 1 University Ave., Lowell, MA 01854, United States
| | - Na Kong
- KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm, Sweden
| | - Oscar Norberg
- KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm, Sweden
| | - Olof Ramström
- KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm, Sweden
| | - Mingdi Yan
- Department of Chemistry, University of Massachusetts Lowell, 1 University Ave., Lowell, MA 01854, United States
- KTH-Royal Institute of Technology, Department of Chemistry, Teknikringen 30, S-10044 Stockholm, Sweden
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32
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Kim DY, Kwon DY, Kwon JS, Kim JH, Min BH, Kim MS. Stimuli-Responsive InjectableIn situ-Forming Hydrogels for Regenerative Medicines. POLYM REV 2015. [DOI: 10.1080/15583724.2014.983244] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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33
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Drack M, Graz I, Sekitani T, Someya T, Kaltenbrunner M, Bauer S. An imperceptible plastic electronic wrap. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:34-40. [PMID: 25332107 PMCID: PMC4315904 DOI: 10.1002/adma.201403093] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/26/2014] [Indexed: 05/18/2023]
Abstract
Extremely compliant sub-2-μm sensor films enable temperature mapping on complex 3D objects, like integrated circuits on printed circuit boards, food packages, and on human skin. In their stretchable form, these metal films withstand strains up to 275%. This imperceptible electronic foil technology platform offers new avenues for the design of complex, hybrid rigid-island stretchable-interconnect electronic devices such as RGB light-emitting diode (LED) strips that can be stretched and twisted without impairing their function.
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Affiliation(s)
- Michael Drack
- Department of Soft Matter Physics Johannes Kepler UniversityAltenbergerstrasse 69, 4040, Linz, Austria E-mail:
| | - Ingrid Graz
- Department of Soft Matter Physics Johannes Kepler UniversityAltenbergerstrasse 69, 4040, Linz, Austria E-mail:
| | - Tsuyoshi Sekitani
- Electrical and Electronic Engineering and Information Systems The University of Tokyo7–3–1 Hongo, Bunkyo-ku, Tokyo, 113–8656, Japan
- Exploratory Research for Advanced Technology (ERATO) Japan Science and Technology Agency (JST)2–11–16, Yayoi, Bunkyo-ku, Tokyo, 113–0032, Japan
| | - Takao Someya
- Electrical and Electronic Engineering and Information Systems The University of Tokyo7–3–1 Hongo, Bunkyo-ku, Tokyo, 113–8656, Japan
- Exploratory Research for Advanced Technology (ERATO) Japan Science and Technology Agency (JST)2–11–16, Yayoi, Bunkyo-ku, Tokyo, 113–0032, Japan
| | - Martin Kaltenbrunner
- Department of Soft Matter Physics Johannes Kepler UniversityAltenbergerstrasse 69, 4040, Linz, Austria E-mail:
| | - Siegfried Bauer
- Department of Soft Matter Physics Johannes Kepler UniversityAltenbergerstrasse 69, 4040, Linz, Austria E-mail:
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34
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Fritzsche N, Pretsch T. Programming of Temperature-Memory Onsets in a Semicrystalline Polyurethane Elastomer. Macromolecules 2014. [DOI: 10.1021/ma501171p] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nikolaus Fritzsche
- BAM Federal
Institute for
Materials Research and Testing, Division 6.5, Polymers in Life Science and Nanotechnology, Unter den Eichen 87, 12205 Berlin, Germany
| | - Thorsten Pretsch
- BAM Federal
Institute for
Materials Research and Testing, Division 6.5, Polymers in Life Science and Nanotechnology, Unter den Eichen 87, 12205 Berlin, Germany
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Abstract
Decades of technological developments have populated the field of neuroprosthetics with myriad replacement strategies, neuromodulation therapies, and rehabilitation procedures to improve the quality of life for individuals with neuromotor disorders. Despite the few but impressive clinical successes, and multiple breakthroughs in animal models, neuroprosthetic technologies remain mainly confined to sophisticated laboratory environments. We summarize the core principles and latest achievements in neuroprosthetics, but also address the challenges that lie along the path toward clinical fruition. We propose a pragmatic framework to personalize neurotechnologies and rehabilitation for patient-specific impairments to achieve the timely dissemination of neuroprosthetic medicine.
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Affiliation(s)
- David Borton
- Center for Neuroprosthetics and Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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36
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Bensmaia SJ, Miller LE. Restoring sensorimotor function through intracortical interfaces: progress and looming challenges. Nat Rev Neurosci 2014; 15:313-25. [PMID: 24739786 DOI: 10.1038/nrn3724] [Citation(s) in RCA: 260] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The loss of a limb or paralysis resulting from spinal cord injury has devastating consequences on quality of life. One approach to restoring lost sensory and motor abilities in amputees and patients with tetraplegia is to supply them with implants that provide a direct interface with the CNS. Such brain-machine interfaces might enable a patient to exert voluntary control over a prosthetic or robotic limb or over the electrically induced contractions of paralysed muscles. A parallel interface could convey sensory information about the consequences of these movements back to the patient. Recent developments in the algorithms that decode motor intention from neuronal activity and in approaches to convey sensory feedback by electrically stimulating neurons, using biomimetic and adaptation-based approaches, have shown the promise of invasive interfaces with sensorimotor cortices, although substantial challenges remain.
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Affiliation(s)
- Sliman J Bensmaia
- Department of Organismal Biology and Anatomy, and Committee on Computational Neuroscience, University of Chicago, Chicago, Illinois 60637, USA
| | - Lee E Miller
- 1] Department of Physical Medicine and Rehabilitation, and Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA. [2] Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA
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37
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Potter KA, Jorfi M, Householder KT, Foster EJ, Weder C, Capadona JR. Curcumin-releasing mechanically adaptive intracortical implants improve the proximal neuronal density and blood-brain barrier stability. Acta Biomater 2014; 10:2209-22. [PMID: 24468582 DOI: 10.1016/j.actbio.2014.01.018] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 12/09/2013] [Accepted: 01/15/2014] [Indexed: 10/25/2022]
Abstract
The cellular and molecular mechanisms by which neuroinflammatory pathways respond to and propagate the reactive tissue response to intracortical microelectrodes remain active areas of research. We previously demonstrated that both the mechanical mismatch between rigid implants and the much softer brain tissue, as well as oxidative stress, contribute to the neurodegenerative reactive tissue response to intracortical implants. In this study, we utilize physiologically responsive, mechanically adaptive polymer implants based on poly(vinyl alcohol) (PVA), with the capability to also locally administer the antioxidant curcumin. The goal of this study is to investigate if the combination of two independently effective mechanisms - softening of the implant and antioxidant release - leads to synergistic effects in vivo. Over the first 4weeks of the implantation, curcumin-releasing, mechanically adaptive implants were associated with higher neuron survival and a more stable blood-brain barrier at the implant-tissue interface than the neat PVA controls. 12weeks post-implantation, the benefits of the curcumin release were lost, and both sets of compliant materials (with and without curcumin) had no statistically significant differences in neuronal density distribution profiles. Overall, however, the curcumin-releasing softening polymer implants cause minimal implant-mediated neuroinflammation, and embody the new concept of localized drug delivery from mechanically adaptive intracortical implants.
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38
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Chen JK, Chang CJ. Fabrications and Applications of Stimulus-Responsive Polymer Films and Patterns on Surfaces: A Review. MATERIALS (BASEL, SWITZERLAND) 2014; 7:805-875. [PMID: 28788489 PMCID: PMC5453090 DOI: 10.3390/ma7020805] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 01/10/2014] [Accepted: 01/16/2014] [Indexed: 11/17/2022]
Abstract
In the past two decades, we have witnessed significant progress in developing high performance stimuli-responsive polymeric materials. This review focuses on recent developments in the preparation and application of patterned stimuli-responsive polymers, including thermoresponsive layers, pH/ionic-responsive hydrogels, photo-responsive film, magnetically-responsive composites, electroactive composites, and solvent-responsive composites. Many important new applications for stimuli-responsive polymers lie in the field of nano- and micro-fabrication, where stimuli-responsive polymers are being established as important manipulation tools. Some techniques have been developed to selectively position organic molecules and then to obtain well-defined patterned substrates at the micrometer or submicrometer scale. Methods for patterning of stimuli-responsive hydrogels, including photolithography, electron beam lithography, scanning probe writing, and printing techniques (microcontact printing, ink-jet printing) were surveyed. We also surveyed the applications of nanostructured stimuli-responsive hydrogels, such as biotechnology (biological interfaces and purification of biomacromoles), switchable wettability, sensors (optical sensors, biosensors, chemical sensors), and actuators.
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Affiliation(s)
- Jem-Kun Chen
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Section 4, Keelung Road, Taipei 106, Taiwan.
| | - Chi-Jung Chang
- Department of Chemical Engineering, Feng Chia University, 100 Wenhwa Road, Seatwen, Taichung 40724, Taiwan.
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39
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Ware T, Simon D, Hearon K, Kang TH, Maitland DJ, Voit W. Thiol-click chemistries for responsive neural interfaces. Macromol Biosci 2013; 13:1640-7. [PMID: 24115484 PMCID: PMC4817906 DOI: 10.1002/mabi.201300272] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/22/2013] [Indexed: 11/11/2022]
Abstract
Neural interfaces provide an electrical connection between computers and the nervous system: current penetrating devices are orders-of-magnitude stiffer than surrounding tissue. In this work, recent efforts in softening electronics and utilize thiol-ene and thiol-epoxy "click" reactions are built upon to incorporate fluid-sensitive hydrogen bonding into smart substrates for high electrode density neural interfaces. The modulus of these substrates drops more than two orders of magnitude in response to physiological conditions, despite fluid uptake of less than 6%, and can be tuned by the covalent crosslink density and degree of hydrogen bonding in the polymer network. Intracortical and intrafascicular electrode arrays are fabricated and characterized with impedance spectroscopy and cyclic voltammetry.
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Affiliation(s)
- Taylor Ware
- Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Rd, Mailstop RL 3, Richardson, TX, 75080, USA
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