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Richie J, Letner JG, Mclane-Svoboda A, Huan Y, Ghaffari DH, Valle ED, Patel PR, Chiel HJ, Pelled G, Weiland JD, Chestek CA. Fabrication and Validation of Sub-Cellular Carbon Fiber Electrodes. IEEE Trans Neural Syst Rehabil Eng 2024; 32:739-749. [PMID: 38294928 PMCID: PMC10919889 DOI: 10.1109/tnsre.2024.3360866] [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] [Indexed: 02/02/2024]
Abstract
Multielectrode arrays for interfacing with neurons are of great interest for a wide range of medical applications. However, current electrodes cause damage over time. Ultra small carbon fibers help to address issues but controlling the electrode site geometry is difficult. Here we propose a methodology to create small, pointed fiber electrodes (SPFe). We compare the SPFe to previously made blowtorched fibers in characterization. The SPFe result in small site sizes [Formula: see text] with consistently sharp points (20.8 ± 7.64°). Additionally, these electrodes were able to record and/or stimulate neurons multiple animal models including rat cortex, mouse retina, Aplysia ganglia and octopus axial cord. In rat cortex, these electrodes recorded significantly higher peak amplitudes than the traditional blowtorched fibers. These SPFe may be applicable to a wide range of applications requiring a highly specific interface with individual neurons.
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2
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Morales AW, Du J, Warren DJ, Fernández-Jover E, Martinez-Navarrete G, Bouteiller JMC, McCreery DC, Lazzi G. Machine learning enables non-Gaussian investigation of changes to peripheral nerves related to electrical stimulation. Sci Rep 2024; 14:2795. [PMID: 38307915 PMCID: PMC10837107 DOI: 10.1038/s41598-024-53284-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 01/30/2024] [Indexed: 02/04/2024] Open
Abstract
Electrical stimulation of the peripheral nervous system (PNS) is becoming increasingly important for the therapeutic treatment of numerous disorders. Thus, as peripheral nerves are increasingly the target of electrical stimulation, it is critical to determine how, and when, electrical stimulation results in anatomical changes in neural tissue. We introduce here a convolutional neural network and support vector machines for cell segmentation and analysis of histological samples of the sciatic nerve of rats stimulated with varying current intensities. We describe the methodologies and present results that highlight the validity of the approach: machine learning enabled highly efficient nerve measurement collection, while multivariate analysis revealed notable changes to nerves' anatomy, even when subjected to levels of stimulation thought to be safe according to the Shannon current limits.
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Affiliation(s)
- Andres W Morales
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA.
| | - Jinze Du
- Department of Electrical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
| | - David J Warren
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, 84112, USA
| | | | | | - Jean-Marie C Bouteiller
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
- Institute for Technology and Medical Systems (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
| | | | - Gianluca Lazzi
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Electrical Engineering, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Ophthalmology, University of Southern California, Los Angeles, CA, 90089, USA
- Institute for Technology and Medical Systems (ITEMS), Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
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Arora JS, Kim JK, Pakvasa M, Sayadi LR, Lem M, Widgerow AD, Leis AR. Microsurgical Needle Retention Does Not Cause Pain or Neurovascular Injury in a Rat Model. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2023; 11:e5171. [PMID: 37547344 PMCID: PMC10402969 DOI: 10.1097/gox.0000000000005171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 06/20/2023] [Indexed: 08/08/2023]
Abstract
Approximately 20% of retained foreign bodies are surgical needles. Retained macro-needles may become symptomatic, but the effect of microsurgical needles is uncertain. We present the first animal model to simulate microsurgical needle retention. Given a lack of reported adverse outcomes associated with macro-needles and a smaller cutting area of microsurgical needles, we hypothesized that microsurgical needles in rats would not cause changes in health or neurovascular compromise. Methods Male Sprague-Dawley rats (x̄ weight: 288.9 g) were implanted with a single, 9.0 needle (n = 8) or 8.0 needle (n = 8) orthogonal to the right femoral vessels and sutured in place. A control group (n = 8) underwent sham surgery. Weekly, a cumulative health score evaluating body weight, body condition score, physical appearance, and behavior for each rat was determined. Infrared thermography (°C, FLIR one) of each hindlimb and the difference was obtained on postoperative days 15, 30, 60, and 90. On day 90, animals were euthanatized, hindlimbs were imaged via fluoroscopy, and needles were explanted. Results The mean, cumulative health score for all cohorts at each weekly timepoint was 0. The mean temperature difference was not significantly different on postoperative days 15 (P = 0.54), 30 (P = 0.97), 60 (P = 0.29), or 90 (P = 0.09). In seven of eight rats, 8.0 needles were recovered and visualized on fluoroscopy. In six of eight rats, 9.0 needles were recovered, but 0/8 needles were visualized on fluoroscopy. Conclusions Microsurgical needle retention near neurovascular structures may be benign, and imaging for needles smaller than 8.0 may be futile. Further studies should explore microsurgical needle retention potentially through larger animal models.
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Affiliation(s)
- Jagmeet S. Arora
- From the School of Medicine, University of California Irvine, Orange, Calif
| | | | - Mikhail Pakvasa
- Department of Plastic Surgery, University of California Irvine, Orange, Calif
| | - Lohrasb R. Sayadi
- Department of Plastic Surgery, University of California Irvine, Orange, Calif
| | - Melinda Lem
- From the School of Medicine, University of California Irvine, Orange, Calif
| | - Alan D. Widgerow
- Center for Tissue Engineering, Department of Plastic Surgery, University of California Irvine, Orange, Calif
| | - Amber R. Leis
- Department of Plastic Surgery, University of California Irvine, Orange, Calif
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Valle G, Aiello G, Ciotti F, Cvancara P, Martinovic T, Kravic T, Navarro X, Stieglitz T, Bumbasirevic M, Raspopovic S. Multifaceted understanding of human nerve implants to design optimized electrodes for bioelectronics. Biomaterials 2022; 291:121874. [DOI: 10.1016/j.biomaterials.2022.121874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 10/23/2022] [Indexed: 11/24/2022]
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Xiong Z, Huang W, Liang Q, Cao Y, Liu S, He Z, Zhang R, Zhang B, Green R, Zhang S, Li D. Harnessing the 2D Structure-Enabled Viscoelasticity of Graphene-Based Hydrogel Membranes for Chronic Neural Interfacing. SMALL METHODS 2022; 6:e2200022. [PMID: 35261208 DOI: 10.1002/smtd.202200022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/20/2022] [Indexed: 06/14/2023]
Abstract
Stiffness and viscoelasticity of neural implants regulate the foreign body response. Recent studies have suggested the use of elastic or viscoelastic materials with tissue-like stiffness for long-term neural electrical interfacing. Herein, the authors find that a viscoelastic multilayered graphene hydrogel (MGH) membrane, despite exhibiting a much higher Young's modulus than nerve tissues, shows little inflammatory response after 8-week implantation in rat sciatic nerves. The MGH membrane shows significant viscoelasticity due to the slippage between graphene nanosheets, facilitating its seamless yet minimally compressive interfacing with nerves to reduce the inflammation caused by the stiffness mismatch. When used as neural stimulation electrodes, the MGH membrane can offer abundant ion-accessible surfaces to bring a charge injection capacity 1-2 orders of magnitude higher than its traditional Pt counterpart, and further demonstrates chronic neural therapy potential in low-voltage modulation of rat blood pressure. This work suggests that the emergence of 2D nanomaterials and particularly their unique structural attributes can be harnessed to enable new bio-interfacing design strategies.
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Affiliation(s)
- Zhiyuan Xiong
- Department of Radiology, The First Affiliated Hospital of Jinan University, Guangzhou, 510632, China
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Wenhui Huang
- Department of Radiology, The First Affiliated Hospital of Jinan University, Guangzhou, 510632, China
| | - Qinghua Liang
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Yang Cao
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Shuyi Liu
- Department of Radiology, The First Affiliated Hospital of Jinan University, Guangzhou, 510632, China
| | - Zicong He
- Department of Radiology, The First Affiliated Hospital of Jinan University, Guangzhou, 510632, China
| | - Ranran Zhang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Bin Zhang
- Department of Radiology, The First Affiliated Hospital of Jinan University, Guangzhou, 510632, China
| | - Rylie Green
- Department of Bioengineering, Imperial College, London, SW7 2AZ, UK
| | - Shuixing Zhang
- Department of Radiology, The First Affiliated Hospital of Jinan University, Guangzhou, 510632, China
| | - Dan Li
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria, 3010, Australia
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Sawyer M, Ferzoco S, DeNoto G. A Polymer-Biologic Hybrid Hernia Construct: Review of Data and Early Experiences. Polymers (Basel) 2021; 13:polym13121928. [PMID: 34200591 PMCID: PMC8228560 DOI: 10.3390/polym13121928] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/04/2021] [Accepted: 06/07/2021] [Indexed: 12/17/2022] Open
Abstract
Surgical mesh reinforcement of the human abdominal wall has been found to reduce the chance of recurrence in hernia repairs. While traditionally polymer meshes have been used in hernia repair, alternative mesh options have been engineered to prevent the inflammatory foreign body response invoked by polymers. A reinforced tissue matrix (RTM) mesh has been developed by embedding a polymer within a decellularized extracellular matrix. This combination has been attributed to the recruitment of host cells, a pro-healing response, and attenuation of the foreign body response. This has been observed to lead to the regeneration of functional tissue within the repair site that is reinforced by the polymer to offload abdominal pressures over time. This manuscript presents the review of OviTex, an RTM, in several types of hernia repair. The authors have found that the use of RTM in hernia repair is effective in preventing foreign body response, promoting wound healing, and providing reinforcement to lower the risk of hernia recurrence.
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Affiliation(s)
- Michael Sawyer
- Department of Surgery, Oklahoma State University, Comanche County Memorial Hospital, Lawton, OK 73505, USA
- Correspondence:
| | - Stephen Ferzoco
- Department of Surgery, Atrius Health, Dedham, MA 02026, USA;
| | - George DeNoto
- General Surgery Department, St. Francis Hospital, Roslyn, NY 11576, USA;
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Kim TY, Shin S, Choi H, Jeong SH, Myung D, Hahn SK. Smart Contact Lenses with a Transparent Silver Nanowire Strain Sensor for Continuous Intraocular Pressure Monitoring. ACS APPLIED BIO MATERIALS 2021; 4:4532-4541. [PMID: 35006789 PMCID: PMC10867858 DOI: 10.1021/acsabm.1c00267] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Continuous intraocular pressure (IOP) monitoring can provide a paradigm shift in the management of patients with glaucoma as a facile alternative to conventional diagnostic methods. However, the low sensitivity and functional instability of current IOP sensors have limited their clinical utility in the management of glaucoma. Here, we have developed a smart contact lens integrated with a transparent silver nanowire IOP strain sensor and wireless circuits for noninvasive, continuous IOP monitoring. After confirming the robust stability of the IOP sensor within the smart contact lens in the presence of tears and repeated eyelid blink model cycles, we were able to monitor IOP changes on polydimethylsiloxane model eyes in vitro. In vivo tests demonstrated that our fully integrated wireless smart contact lens could successfully monitor the change in IOP in living rabbit eyes, which was clearly validated by the conventional invasive tonometer IOP test. Taken together, we could confirm the feasibility of our smart contact lens as a noninvasive platform for continuous IOP monitoring of glaucoma patients.
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Affiliation(s)
- Tae Yeon Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Korea
| | - Sangbaie Shin
- PHI BIOMED Co., 168 Yeoksam-ro, Gangnam-gu, Seoul 06248, South Korea
| | - Hyunsik Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Korea
| | - Sang Hoon Jeong
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Korea
| | - David Myung
- Department of Ophthalmology and Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States
| | - Sei Kwang Hahn
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Korea
- PHI BIOMED Co., 168 Yeoksam-ro, Gangnam-gu, Seoul 06248, South Korea
- Department of Ophthalmology and Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States
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8
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Carnicer-Lombarte A, Chen ST, Malliaras GG, Barone DG. Foreign Body Reaction to Implanted Biomaterials and Its Impact in Nerve Neuroprosthetics. Front Bioeng Biotechnol 2021; 9:622524. [PMID: 33937212 PMCID: PMC8081831 DOI: 10.3389/fbioe.2021.622524] [Citation(s) in RCA: 133] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/19/2021] [Indexed: 12/04/2022] Open
Abstract
The implantation of any foreign material into the body leads to the development of an inflammatory and fibrotic process-the foreign body reaction (FBR). Upon implantation into a tissue, cells of the immune system become attracted to the foreign material and attempt to degrade it. If this degradation fails, fibroblasts envelop the material and form a physical barrier to isolate it from the rest of the body. Long-term implantation of medical devices faces a great challenge presented by FBR, as the cellular response disrupts the interface between implant and its target tissue. This is particularly true for nerve neuroprosthetic implants-devices implanted into nerves to address conditions such as sensory loss, muscle paralysis, chronic pain, and epilepsy. Nerve neuroprosthetics rely on tight interfacing between nerve tissue and electrodes to detect the tiny electrical signals carried by axons, and/or electrically stimulate small subsets of axons within a nerve. Moreover, as advances in microfabrication drive the field to increasingly miniaturized nerve implants, the need for a stable, intimate implant-tissue interface is likely to quickly become a limiting factor for the development of new neuroprosthetic implant technologies. Here, we provide an overview of the material-cell interactions leading to the development of FBR. We review current nerve neuroprosthetic technologies (cuff, penetrating, and regenerative interfaces) and how long-term function of these is limited by FBR. Finally, we discuss how material properties (such as stiffness and size), pharmacological therapies, or use of biodegradable materials may be exploited to minimize FBR to nerve neuroprosthetic implants and improve their long-term stability.
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Affiliation(s)
- Alejandro Carnicer-Lombarte
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Shao-Tuan Chen
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - George G. Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Damiano G. Barone
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, United Kingdom
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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Yang F, Zhang X, Huang H, Wu G, Lippuner K, Hunziker EB. Anticytokine Activity Enhances Osteogenesis of Bioactive Implants. Tissue Eng Part A 2020; 27:177-186. [PMID: 32536255 DOI: 10.1089/ten.tea.2020.0067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In dental clinical practice, systemic steroids are often applied at the end of implant surgeries to reduce postsurgical inflammation (tissue swelling, etc.) and to reduce patient discomfort. However, the use of systemic steroids is associated with generalized catabolic effects and with a temporarily reduced immunological competence. We hypothesize that by applying locally anticytokine antibodies (antitumor necrosis factor alpha and anti-interleukin-1 beta) together with a bioactive osteogenic implant at the time of the surgical intervention for the placement of a construct, we will be able to achieve the same beneficial effects as those using systemic steroids but are able to avoid the generalized antianabolic effects and the reduced immunocompetence effects, associated with the systemic use of steroids. In an adult rat model, a collagen sponge, soaked with the osteogenic agent bone morphogenetic protein-2, was used as an example for a bioactive implant material and was surgically placed subcutaneously. In the acute inflammatory phase after implantation (2 days after surgery) we investigated the local inflammatory tissue response, and 18 days postsurgically the efficiency of local osteogenesis (to assess possible antianabolic effects). We found that the negative control groups, treated postsurgically with systemic steroids, showed a significant suppression of both the inflammatory response and the osteogenetic activity, that is, they were associated with significant general antianabolic effects, even when steroids were used only at a low dose level. The local anticytokine treatment, however, was able to significantly enhance new bone formation activity, that is, the anabolic activity, over positive control values with BMP-2 only. However, the anticytokine treatment was unable to reduce the local inflammatory and swelling responses.
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Affiliation(s)
- Fan Yang
- Department of Stomatology, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou, China
| | - Xin Zhang
- Department of Human Movement Sciences, Faculty of Behavioral and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Hairong Huang
- Department of Osteoporosis, Inselspital Bern University Hospital, Bern, Switzerland
| | - Gang Wu
- Department of Oral Implantology and Prosthetic Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije University Amsterdam, Amsterdam, The Netherlands
| | - Kurt Lippuner
- Department of Osteoporosis, Inselspital Bern University Hospital, Bern, Switzerland
| | - Ernst B Hunziker
- Departments of Osteoporosis and Orthopedic Surgery, Inselspital Bern University Hospital, Bern, Switzerland
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10
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Dewberry LS, Dru A, Gravenstine M, Nguyen B, Anderson J, Vaziri S, Hoh D, Allen K, Otto KJ. Partial high frequency nerve block decreases neuropathic signaling following chronic sciatic nerve constriction injury. J Neural Eng 2020; 18. [PMID: 33027782 DOI: 10.1088/1741-2552/abbf03] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 10/07/2020] [Indexed: 11/11/2022]
Abstract
OBJECTIVE High frequency (HF) block can quickly and reversibly stop nerve conduction. We hypothesized HF block at the sciatic nerve would minimize nociception by preventing neuropathic signals from reaching the central nervous system. APPROACH Lewis rats were implanted with a constriction cuff and a distal cuff electrode around their right sciatic nerve. Tactile sensitivity was evaluated using the 50% paw withdrawal threshold determined using Chaplan's method for von Frey monofilaments. Over the course of 49 days, the 50% paw withdrawal threshold was measured 1) before HF block, 2) during HF block (50 kHz, 3 Vpp), and 3) after HF block. Gait was observed and scored before and during block. At end point, HF block efficacy was directly evaluated using additional cuff electrodes to elicit and record compound neural action potentials across the HF blocking cuff. MAIN RESULTS At days 7 and 14 days post-operation, tactile sensitivity was significantly lower during HF block compared to before and after block (p < 0.005). Additionally, an increase in gait disability was not visually observed during HF block. SIGNIFICANCE HF block can reduce tactile sensitivity in a limb with a neuropthic injury in a rapidly reversible fashion.
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Affiliation(s)
- Lauren Savannah Dewberry
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive, Biomedical Sciences Building JG56, Gainesville, FL 32611-6131, Gainesville, Florida, 32611-7011, UNITED STATES
| | - Alexander Dru
- Lillian S. Wells Department of Neurosurgery, University of Florida, Gainesville, Florida, UNITED STATES
| | - Maxwell Gravenstine
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, UNITED STATES
| | - Brian Nguyen
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, UNITED STATES
| | - James Anderson
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, UNITED STATES
| | - Sasha Vaziri
- Lillian S. Wells Department of Neurosurgery, University of Florida, Gainesville, Florida, UNITED STATES
| | - Daniel Hoh
- Lillian S. Wells Department of Neurosurgery, University of Florida, Gainesville, Florida, UNITED STATES
| | - Kyle Allen
- Department of Biomedical Engineering, University of Florida, P.O. Box 116131, USA, Gainesville, Florida, 32611-6131, UNITED STATES
| | - Kevin J Otto
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, 32611-7011, UNITED STATES
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11
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A review for the peripheral nerve interface designer. J Neurosci Methods 2019; 332:108523. [PMID: 31743684 DOI: 10.1016/j.jneumeth.2019.108523] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 12/11/2022]
Abstract
Informational density and relative accessibility of the peripheral nervous system make it an attractive site for therapeutic intervention. Electrode-based electrophysiological interfaces with peripheral nerves have been under development since the 1960s and, for several applications, have seen widespread clinical implementation. However, many applications require a combination of neural target resolution and stability which has thus far eluded existing peripheral nerve interfaces (PNIs). With the goal of aiding PNI designers in development of devices that meet the demands of next-generation applications, this review seeks to collect and present practical considerations and best practices which emerge from the literature, including both lessons learned during early PNI development and recent ideas. Fundamental and practical principles guiding PNI design are reviewed, followed by an updated and critical account of existing PNI designs and strategies. Finally, a brief survey of in vitro and in vivo PNI characterization methods is presented.
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González-González MA, Kanneganti A, Joshi-Imre A, Hernandez-Reynoso AG, Bendale G, Modi R, Ecker M, Khurram A, Cogan SF, Voit WE, Romero-Ortega MI. Thin Film Multi-Electrode Softening Cuffs for Selective Neuromodulation. Sci Rep 2018; 8:16390. [PMID: 30401906 PMCID: PMC6219541 DOI: 10.1038/s41598-018-34566-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 10/18/2018] [Indexed: 01/21/2023] Open
Abstract
Silicone nerve cuff electrodes are commonly implanted on relatively large and accessible somatic nerves as peripheral neural interfaces. While these cuff electrodes are soft (1–50 MPa), their self-closing mechanism requires of thick walls (200–600 µm), which in turn contribute to fibrotic tissue growth around and inside the device, compromising the neural interface. We report the use of thiol-ene/acrylate shape memory polymer (SMP) for the fabrication of thin film multi-electrode softening cuffs (MSC). We fabricated multi-size MSC with eight titanium nitride (TiN) electrodes ranging from 1.35 to 13.95 × 10−4 cm2 (1–3 kΩ) and eight smaller gold (Au) electrodes (3.3 × 10−5 cm2; 750 kΩ), that soften at physiological conditions to a modulus of 550 MPa. While the SMP material is not as soft as silicone, the flexural forces of the SMP cuff are about 70–700 times lower in the MSC devices due to the 30 μm thick film compared to the 600 μm thick walls of the silicone cuffs. We demonstrated the efficacy of the MSC to record neural signals from rat sciatic and pelvic nerves (1000 µm and 200 µm diameter, respectively), and the selective fascicular stimulation by current steering. When implanted side-by-side and histologically compared 30 days thereafter, the MSC devices showed significantly less inflammation, indicated by a 70–80% reduction in ED1 positive macrophages, and 54–56% less fibrotic vimentin immunoreactivity. Together, the data supports the use of MSC as compliant and adaptable technology for the interfacing of somatic and autonomic peripheral nerves.
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Affiliation(s)
- María A González-González
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Aswini Kanneganti
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Alexandra Joshi-Imre
- Department of Material Science and Engineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Ana G Hernandez-Reynoso
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Geetanjali Bendale
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Romil Modi
- Department of Material Science and Engineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Melanie Ecker
- Department of Material Science and Engineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Ali Khurram
- Department of Material Science and Engineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Stuart F Cogan
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Walter E Voit
- Department of Material Science and Engineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA
| | - Mario I Romero-Ortega
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX, 75080, USA.
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13
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de la Oliva N, Mueller M, Stieglitz T, Navarro X, Del Valle J. On the use of Parylene C polymer as substrate for peripheral nerve electrodes. Sci Rep 2018; 8:5965. [PMID: 29654317 PMCID: PMC5899141 DOI: 10.1038/s41598-018-24502-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/05/2018] [Indexed: 12/31/2022] Open
Abstract
Parylene C is a highly flexible polymer used in several biomedical implants. Since previous studies have reported valuable biocompatible and manufacturing characteristics for brain and intraneural implants, we tested its suitability as a substrate for peripheral nerve electrodes. We evaluated 1-year-aged in vitro samples, where no chemical differences were observed and only a slight deviation on Young’s modulus was found. The foreign body reaction (FBR) to longitudinal Parylene C devices implanted in the rat sciatic nerve for 8 months was characterized. After 2 weeks, a capsule was formed around the device, which continued increasing up to 16 and 32 weeks. Histological analyses revealed two cell types implicated in the FBR: macrophages, in contact with the device, and fibroblasts, localized in the outermost zone after 8 weeks. Molecular analysis of implanted nerves comparing Parylene C and polyimide devices revealed a peak of inflammatory cytokines after 1 day of implant, returning to low levels thereafter. Only an increase of CCL2 and CCL3 was found at chronic time-points for both materials. Although no molecular differences in the FBR to both polymers were found, the thick tissue capsule formed around Parylene C puts some concern on its use as a scaffold for intraneural electrodes.
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Affiliation(s)
- Natàlia de la Oliva
- Institute of Neurosciences, Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Matthias Mueller
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, Albert-Ludwig-University Freiburg, Freiburg, Germany
| | - Thomas Stieglitz
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering-IMTEK, Albert-Ludwig-University Freiburg, Freiburg, Germany
| | - Xavier Navarro
- Institute of Neurosciences, Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Jaume Del Valle
- Institute of Neurosciences, Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain. .,Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain.
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