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Huang S, Ren C, Luo Y, Ding Y, Ji X, Li S. New insights into the roles of oligodendrocytes regulation in ischemic stroke recovery. Neurobiol Dis 2023:106200. [PMID: 37321419 DOI: 10.1016/j.nbd.2023.106200] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/20/2023] [Accepted: 06/12/2023] [Indexed: 06/17/2023] Open
Abstract
Oligodendrocytes (OLs), the myelin-forming cells of the central nervous system, are integral to axonal integrity and function. Hypoxia-ischemia episodes can cause severe damage to these vulnerable cells through excitotoxicity, oxidative stress, inflammation, and mitochondrial dysfunction, leading to axonal dystrophy, neuronal dysfunction, and neurological impairments. OLs damage can result in demyelination and myelination disorders, severely impacting axonal function, structure, metabolism, and survival. Adult-onset stroke, periventricular leukomalacia, and post-stroke cognitive impairment primarily target OLs, making them a critical therapeutic target. Therapeutic strategies targeting OLs, myelin, and their receptors should be given more emphasis to attenuate ischemia injury and establish functional recovery after stroke. This review summarizes recent advances on the function of OLs in ischemic injury, as well as the present and emerging principles that serve as the foundation for protective strategies against OL deaths.
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Affiliation(s)
- Shuangfeng Huang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China; Department of Emergency, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Changhong Ren
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China; Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yumin Luo
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China; Institute of Cerebrovascular Diseases Research and Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yuchuan Ding
- Department of Neurosurgery, Wayne State University, Detroit, MI, USA
| | - Xunming Ji
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China; Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China.
| | - Sijie Li
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China; Department of Emergency, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China.
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2
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Hnatko M, Hičák M, Labudová M, Galusková D, Sedláček J, Lenčéš Z, Šajgalík P. Bioactive silicon nitride by surface thermal treatment. Ann Ital Chir 2020. [DOI: 10.1016/j.jeurceramsoc.2019.12.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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3
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Obidin N, Tasnim F, Dagdeviren C. The Future of Neuroimplantable Devices: A Materials Science and Regulatory Perspective. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1901482. [PMID: 31206827 DOI: 10.1002/adma.201901482] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/12/2019] [Indexed: 06/09/2023]
Abstract
The past two decades have seen unprecedented progress in the development of novel materials, form factors, and functionalities in neuroimplantable technologies, including electrocorticography (ECoG) systems, multielectrode arrays (MEAs), Stentrode, and deep brain probes. The key considerations for the development of such devices intended for acute implantation and chronic use, from the perspective of biocompatible hybrid materials incorporation, conformable device design, implantation procedures, and mechanical and biological risk factors, are highlighted. These topics are connected with the role that the U.S. Food and Drug Administration (FDA) plays in its regulation of neuroimplantable technologies based on the above parameters. Existing neuroimplantable devices and efforts to improve their materials and implantation protocols are first discussed in detail. The effects of device implantation with regards to biocompatibility and brain heterogeneity are then explored. Topics examined include brain-specific risk factors, such as bacterial infection, tissue scarring, inflammation, and vasculature damage, as well as efforts to manage these dangers through emerging hybrid, bioelectronic device architectures. The current challenges of gaining clinical approval by the FDA-in particular, with regards to biological, mechanical, and materials risk factors-are summarized. The available regulatory pathways to accelerate next-generation neuroimplantable devices to market are then discussed.
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Affiliation(s)
- Nikita Obidin
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Farita Tasnim
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Canan Dagdeviren
- MIT Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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4
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Gulino M, Kim D, Pané S, Santos SD, Pêgo AP. Tissue Response to Neural Implants: The Use of Model Systems Toward New Design Solutions of Implantable Microelectrodes. Front Neurosci 2019; 13:689. [PMID: 31333407 PMCID: PMC6624471 DOI: 10.3389/fnins.2019.00689] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/18/2019] [Indexed: 01/28/2023] Open
Abstract
The development of implantable neuroelectrodes is advancing rapidly as these tools are becoming increasingly ubiquitous in clinical practice, especially for the treatment of traumatic and neurodegenerative disorders. Electrodes have been exploited in a wide number of neural interface devices, such as deep brain stimulation, which is one of the most successful therapies with proven efficacy in the treatment of diseases like Parkinson or epilepsy. However, one of the main caveats related to the clinical application of electrodes is the nervous tissue response at the injury site, characterized by a cascade of inflammatory events, which culminate in chronic inflammation, and, in turn, result in the failure of the implant over extended periods of time. To overcome current limitations of the most widespread macroelectrode based systems, new design strategies and the development of innovative materials with superior biocompatibility characteristics are currently being investigated. This review describes the current state of the art of in vitro, ex vivo, and in vivo models available for the study of neural tissue response to implantable microelectrodes. We particularly highlight new models with increased complexity that closely mimic in vivo scenarios and that can serve as promising alternatives to animal studies for investigation of microelectrodes in neural tissues. Additionally, we also express our view on the impact of the progress in the field of neural tissue engineering on neural implant research.
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Affiliation(s)
- Maurizio Gulino
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
- FEUP – Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
| | - Donghoon Kim
- Multi-Scale Robotics Lab (MSRL), Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Zurich, Switzerland
| | - Salvador Pané
- Multi-Scale Robotics Lab (MSRL), Institute of Robotics and Intelligent Systems (IRIS), ETH Zurich, Zurich, Switzerland
| | - Sofia Duque Santos
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
| | - Ana Paula Pêgo
- i3S – Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- INEB – Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
- FEUP – Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
- ICBAS – Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
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Gray ME, Meehan J, Blair EO, Ward C, Langdon SP, Morrison LR, Marland JRK, Tsiamis A, Kunkler IH, Murray A, Argyle D. Biocompatibility of common implantable sensor materials in a tumor xenograft model. J Biomed Mater Res B Appl Biomater 2019; 107:1620-1633. [PMID: 30367816 PMCID: PMC6767110 DOI: 10.1002/jbm.b.34254] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/30/2018] [Accepted: 09/09/2018] [Indexed: 12/22/2022]
Abstract
Real-time monitoring of tumor microenvironment parameters using an implanted biosensor could provide valuable information on the dynamic nature of a tumor's biology and its response to treatment. However, following implantation biosensors may lose functionality due to biofouling caused by the foreign body response (FBR). This study developed a novel tumor xenograft model to evaluate the potential of six biomaterials (silicon dioxide, silicon nitride, Parylene-C, Nafion, biocompatible EPOTEK epoxy resin, and platinum) to trigger a FBR when implanted into a solid tumor. Biomaterials were chosen based on their use in the construction of a novel biosensor, designed to measure spatial and temporal changes in intra-tumoral O2 , and pH. None of the biomaterials had any detrimental effect on tumor growth or body weight of the murine host. Immunohistochemistry showed no significant changes in tumor necrosis, hypoxic cell number, proliferation, apoptosis, immune cell infiltration, or collagen deposition. The absence of biofouling supports the use of these materials in biosensors; future investigations in preclinical cancer models are required, with a view to eventual applications in humans. To our knowledge this is the first documented investigation of the effects of modern biomaterials, used in the production of implantable sensors, on tumor tissue after implantation. © 2018 The Authors. Journal of Biomedical Materials Research Part B: Applied Biomaterials published by Wiley Periodicals, Inc. J Biomed Mater Res Part B, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1620-1633, 2019.
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Affiliation(s)
- Mark E. Gray
- The Royal (Dick) School of Veterinary Studies and Roslin InstituteUniversity of EdinburghEdinburghEH25 9RGUK
- Cancer Research UK Edinburgh Centre and Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghEH4 2XUUK
| | - James Meehan
- Cancer Research UK Edinburgh Centre and Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghEH4 2XUUK
- Institute of Sensors, Signals and Systems, School of Engineering and Physical SciencesHeriot‐Watt UniversityEdinburghEH14 4ASUK
| | - Ewen O. Blair
- School of Engineering, Faraday BuildingEdinburghEH9 3JLUK
| | - Carol Ward
- The Royal (Dick) School of Veterinary Studies and Roslin InstituteUniversity of EdinburghEdinburghEH25 9RGUK
- Cancer Research UK Edinburgh Centre and Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghEH4 2XUUK
| | - Simon P. Langdon
- Cancer Research UK Edinburgh Centre and Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghEH4 2XUUK
| | - Linda R. Morrison
- The Royal (Dick) School of Veterinary Studies and Roslin InstituteUniversity of EdinburghEdinburghEH25 9RGUK
| | | | | | - Ian H. Kunkler
- Cancer Research UK Edinburgh Centre and Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghEdinburghEH4 2XUUK
| | - Alan Murray
- School of Engineering, Faraday BuildingEdinburghEH9 3JLUK
| | - David Argyle
- The Royal (Dick) School of Veterinary Studies and Roslin InstituteUniversity of EdinburghEdinburghEH25 9RGUK
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6
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Kristensen BW, Blaabjerg M, Noraberg J, Zimmer J. Long-term, Repeated Dose In Vitro Neurotoxicity of the Glutamate Receptor Antagonist L-AP3, Demonstrated in Rat Hippocampal Slice Cultures by Using Continuous Propidium Iodide Incubation. Altern Lab Anim 2019; 35:211-21. [PMID: 17559310 DOI: 10.1177/026119290703500208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Most in vitro models are only used to assess short-term effects of test compounds. However, as demonstrated here, hippocampal slice cultures can be used for long-term studies. The test compound used was the metabotropic glutamate receptor antagonist, L(+)-2-amino-3-phosphonopropionic acid (L-AP3), which is known to be toxic in vivo after subchronic, but not acute, administration. Degenerative effects were monitored by measuring the cellular uptake of propidium iodide (PI; continuously present in the medium) and lactate dehydrogenase (LDH) leakage, and by using a panel of histological stains. Hippocampal slices, derived from 2-3 day old rats and grown for 3 weeks, were subsequently exposed for the next 3 weeks to 0, 10 or 100microM L-AP3, with PI (2microM) in the culture medium. Exposure to 100microM L-AP3 induced severe toxicity after 4-6 days, shown by massive PI uptake, LDH leakage, changes in MAP2 and GFAP immunostaining, and in Nissl and Timm staining. In contrast, 10microM L-AP3 did not induce detectable neuronal degeneration. Treatment with the NMDA receptor antagonist, MK-801, or the AMPA/KA receptor antagonist NBQX, together with 100microM L-AP3, reduced neurodegeneration down to close to control values. It is concluded that continuous incubation of hippocampal slice cultures with PI is technically feasible for use in studies of inducible neuronal degeneration over time.
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Affiliation(s)
- Bjarne W Kristensen
- Anatomy and Neurobiology, Institute of Medical Biology, University of Southern Denmark, Odense, Denmark
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7
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Noraberg J. Organotypic Brain Slice Cultures: An Efficient and Reliable Method for Neurotoxicological Screening and Mechanistic Studies. Altern Lab Anim 2019; 32:329-37. [PMID: 15651916 DOI: 10.1177/026119290403200403] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This paper reviews the current state of the use of organotypic brain slice cultures for neurotoxicological and neuropharmacological screening and mechanistic studies, as exemplified by excitotoxin application. At present, no in vitro systems have been approved by the regulatory authorities for neurotoxicity testing. For the evaluation of the slice culture method, organotypic hippocampal slice cultures were exposed to toxic doses of the excitotoxins, glutamate, N-methyl-D-aspartate (NMDA), kainic acid and 2-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA), and the glial toxin, DL-alpha-aminoadipic acid (DLAAA). Neuronal cell death was quantified by propidium iodide (PI) uptake, and visualised by Fluoro-Jade (FJ) staining. General cell death was monitored by lactate dehydrogenase (LDH) release into the culture medium. EC50 values for the different compounds, based on PI uptake after exposure for 48 hours in entire cultures, were: glutamate, 3.5 mM; DL-AAA, 2.3 mM; kainic acid, 13 microM; NMDA, 11 microM; and AMPA, 3.7 microM. In the slice cultures, the hippocampal subfields displayed the same differences in vulnerability as those observed in vivo. When subfield analysis was performed on the cultures, the CA1 subfield was most susceptible to glutamate, NMDA and AMPA, while CA3 was most susceptible to kainic acid. The amount of LDH release for DL-AAA was about four times that of L-glutamate, in accordance with the additional toxic effect on glial cells, which was also found by confocal microscopy to stain for FJ. In conclusion, it was found that organotypic brain slice culture, combined with standardised protocols and quantifiable markers, such as PI and FJ staining, is a relevant and feasible in vitro system for neurotoxicity testing. Considering the amount and quality of the available published data, it is recommended that the brain slice culture method could be subjected to pre-validation and formal validation for inclusion in a tiered in vitro neurotoxicity testing scheme to supplement and replace conventional animal tests.
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Affiliation(s)
- Jens Noraberg
- NeuroScreen ApS, Anatomy and Neurobiology, University of Southern Denmark, Winslowparken 21, 5000 Odense, Denmark.
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8
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Martins NRB, Angelica A, Chakravarthy K, Svidinenko Y, Boehm FJ, Opris I, Lebedev MA, Swan M, Garan SA, Rosenfeld JV, Hogg T, Freitas RA. Human Brain/Cloud Interface. Front Neurosci 2019; 13:112. [PMID: 30983948 PMCID: PMC6450227 DOI: 10.3389/fnins.2019.00112] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 01/30/2019] [Indexed: 12/25/2022] Open
Abstract
The Internet comprises a decentralized global system that serves humanity's collective effort to generate, process, and store data, most of which is handled by the rapidly expanding cloud. A stable, secure, real-time system may allow for interfacing the cloud with the human brain. One promising strategy for enabling such a system, denoted here as a "human brain/cloud interface" ("B/CI"), would be based on technologies referred to here as "neuralnanorobotics." Future neuralnanorobotics technologies are anticipated to facilitate accurate diagnoses and eventual cures for the ∼400 conditions that affect the human brain. Neuralnanorobotics may also enable a B/CI with controlled connectivity between neural activity and external data storage and processing, via the direct monitoring of the brain's ∼86 × 109 neurons and ∼2 × 1014 synapses. Subsequent to navigating the human vasculature, three species of neuralnanorobots (endoneurobots, gliabots, and synaptobots) could traverse the blood-brain barrier (BBB), enter the brain parenchyma, ingress into individual human brain cells, and autoposition themselves at the axon initial segments of neurons (endoneurobots), within glial cells (gliabots), and in intimate proximity to synapses (synaptobots). They would then wirelessly transmit up to ∼6 × 1016 bits per second of synaptically processed and encoded human-brain electrical information via auxiliary nanorobotic fiber optics (30 cm3) with the capacity to handle up to 1018 bits/sec and provide rapid data transfer to a cloud based supercomputer for real-time brain-state monitoring and data extraction. A neuralnanorobotically enabled human B/CI might serve as a personalized conduit, allowing persons to obtain direct, instantaneous access to virtually any facet of cumulative human knowledge. Other anticipated applications include myriad opportunities to improve education, intelligence, entertainment, traveling, and other interactive experiences. A specialized application might be the capacity to engage in fully immersive experiential/sensory experiences, including what is referred to here as "transparent shadowing" (TS). Through TS, individuals might experience episodic segments of the lives of other willing participants (locally or remote) to, hopefully, encourage and inspire improved understanding and tolerance among all members of the human family.
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Affiliation(s)
- Nuno R. B. Martins
- Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Center for Research and Education on Aging (CREA), University of California, Berkeley and LBNL, Berkeley, CA, United States
| | | | - Krishnan Chakravarthy
- UC San Diego Health Science, San Diego, CA, United States
- VA San Diego Healthcare System, San Diego, CA, United States
| | | | | | - Ioan Opris
- Miami Project to Cure Paralysis, University of Miami, Miami, FL, United States
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, United States
| | - Mikhail A. Lebedev
- Center for Neuroengineering, Duke University, Durham, NC, United States
- Center for Bioelectric Interfaces of the Institute for Cognitive Neuroscience of the National Research University Higher School of Economics, Moscow, Russia
- Department of Information and Internet Technologies of Digital Health Institute, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Melanie Swan
- Department of Philosophy, Purdue University, West Lafayette, IN, United States
| | - Steven A. Garan
- Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Center for Research and Education on Aging (CREA), University of California, Berkeley and LBNL, Berkeley, CA, United States
| | - Jeffrey V. Rosenfeld
- Monash Institute of Medical Engineering, Monash University, Clayton, VIC, Australia
- Department of Neurosurgery, Alfred Hospital, Melbourne, VIC, Australia
- Department of Surgery, Monash University, Clayton, VIC, Australia
- Department of Surgery, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Tad Hogg
- Institute for Molecular Manufacturing, Palo Alto, CA, United States
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Sim JY, Haney MP, Park SI, McCall JG, Jeong JW. Microfluidic neural probes: in vivo tools for advancing neuroscience. LAB ON A CHIP 2017; 17:1406-1435. [PMID: 28349140 DOI: 10.1039/c7lc00103g] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Microfluidic neural probes hold immense potential as in vivo tools for dissecting neural circuit function in complex nervous systems. Miniaturization, integration, and automation of drug delivery tools open up new opportunities for minimally invasive implants. These developments provide unprecedented spatiotemporal resolution in fluid delivery as well as multifunctional interrogation of neural activity using combined electrical and optical modalities. Capitalizing on these unique features, microfluidic technology will greatly advance in vivo pharmacology, electrophysiology, optogenetics, and optopharmacology. In this review, we discuss recent advances in microfluidic neural probe systems. In particular, we will highlight the materials and manufacturing processes of microfluidic probes, device configurations, peripheral devices for fluid handling and packaging, and wireless technologies that can be integrated for the control of these microfluidic probe systems. This article summarizes various microfluidic implants and discusses grand challenges and future directions for further developments.
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Affiliation(s)
- Joo Yong Sim
- Electronics and Telecommunications Research Institute, Bio-Medical IT Convergence Research Department, Daejeon, 34129, Republic of Korea
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10
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Gong W, Senčar J, Bakkum DJ, Jäckel D, Obien MEJ, Radivojevic M, Hierlemann AR. Multiple Single-Unit Long-Term Tracking on Organotypic Hippocampal Slices Using High-Density Microelectrode Arrays. Front Neurosci 2016; 10:537. [PMID: 27920665 PMCID: PMC5118563 DOI: 10.3389/fnins.2016.00537] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/03/2016] [Indexed: 12/11/2022] Open
Abstract
A novel system to cultivate and record from organotypic brain slices directly on high-density microelectrode arrays (HD-MEA) was developed. This system allows for continuous recording of electrical activity of specific individual neurons at high spatial resolution while monitoring at the same time, neuronal network activity. For the first time, the electrical activity patterns of single neurons and the corresponding neuronal network in an organotypic hippocampal slice culture were studied during several consecutive weeks at daily intervals. An unsupervised iterative spike-sorting algorithm, based on PCA and k-means clustering, was developed to assign the activities to the single units. Spike-triggered average extracellular waveforms of an action potential recorded across neighboring electrodes, termed “footprints” of single-units were generated and tracked over weeks. The developed system offers the potential to study chronic impacts of drugs or genetic modifications on individual neurons in slice preparations over extended times.
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Affiliation(s)
- Wei Gong
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering ETH Zürich, Basel, Switzerland
| | - Jure Senčar
- Faculty of Electrical Engineering, University of Ljubljana Ljubljana, Slovenia
| | - Douglas J Bakkum
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering ETH Zürich, Basel, Switzerland
| | - David Jäckel
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering ETH Zürich, Basel, Switzerland
| | - Marie Engelene J Obien
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering ETH Zürich, Basel, Switzerland
| | - Milos Radivojevic
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering ETH Zürich, Basel, Switzerland
| | - Andreas R Hierlemann
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering ETH Zürich, Basel, Switzerland
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Neural Probes for Chronic Applications. MICROMACHINES 2016; 7:mi7100179. [PMID: 30404352 PMCID: PMC6190051 DOI: 10.3390/mi7100179] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 09/12/2016] [Accepted: 09/26/2016] [Indexed: 12/11/2022]
Abstract
Developed over approximately half a century, neural probe technology is now a mature technology in terms of its fabrication technology and serves as a practical alternative to the traditional microwires for extracellular recording. Through extensive exploration of fabrication methods, structural shapes, materials, and stimulation functionalities, neural probes are now denser, more functional and reliable. Thus, applications of neural probes are not limited to extracellular recording, brain-machine interface, and deep brain stimulation, but also include a wide range of new applications such as brain mapping, restoration of neuronal functions, and investigation of brain disorders. However, the biggest limitation of the current neural probe technology is chronic reliability; neural probes that record with high fidelity in acute settings often fail to function reliably in chronic settings. While chronic viability is imperative for both clinical uses and animal experiments, achieving one is a major technological challenge due to the chronic foreign body response to the implant. Thus, this review aims to outline the factors that potentially affect chronic recording in chronological order of implantation, summarize the methods proposed to minimize each factor, and provide a performance comparison of the neural probes developed for chronic applications.
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12
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Neural Circuits on a Chip. MICROMACHINES 2016; 7:mi7090157. [PMID: 30404330 PMCID: PMC6190100 DOI: 10.3390/mi7090157] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 08/20/2016] [Accepted: 08/29/2016] [Indexed: 02/07/2023]
Abstract
Neural circuits are responsible for the brain's ability to process and store information. Reductionist approaches to understanding the brain include isolation of individual neurons for detailed characterization. When maintained in vitro for several days or weeks, dissociated neurons self-assemble into randomly connected networks that produce synchronized activity and are capable of learning. This review focuses on efforts to control neuronal connectivity in vitro and construct living neural circuits of increasing complexity and precision. Microfabrication-based methods have been developed to guide network self-assembly, accomplishing control over in vitro circuit size and connectivity. The ability to control neural connectivity and synchronized activity led to the implementation of logic functions using living neurons. Techniques to construct and control three-dimensional circuits have also been established. Advances in multiple electrode arrays as well as genetically encoded, optical activity sensors and transducers enabled highly specific interfaces to circuits composed of thousands of neurons. Further advances in on-chip neural circuits may lead to better understanding of the brain.
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13
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Song S, Roy S. Progress and challenges in macroencapsulation approaches for type 1 diabetes (T1D) treatment: Cells, biomaterials, and devices. Biotechnol Bioeng 2016; 113:1381-402. [PMID: 26615050 DOI: 10.1002/bit.25895] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 10/30/2015] [Accepted: 11/24/2015] [Indexed: 12/15/2022]
Abstract
Macroencapsulation technology has been an attractive topic in the field of treatment for Type 1 diabetes due to mechanical stability, versatility, and retrievability of the macro-capsule design. Macro-capsules can be categorized into extravascular and intravascular devices, in which solute transport relies either on diffusion or convection, respectively. Failure of macroencapsulation strategies can be due to limited regenerative capacity of the encased insulin-producing cells, sub-optimal performance of encapsulation biomaterials, insufficient immunoisolation, excessive blood thrombosis for vascular perfusion devices, and inadequate modes of mass transfer to support cell viability and function. However, significant technical advancements have been achieved in macroencapsulation technology, namely reducing diffusion distance for oxygen and nutrients, using pro-angiogenic factors to increase vascularization for islet engraftment, and optimizing membrane permeability and selectivity to prevent immune attacks from host's body. This review presents an overview of existing macroencapsulation devices and discusses the advances based on tissue-engineering approaches that will stimulate future research and development of macroencapsulation technology. Biotechnol. Bioeng. 2016;113: 1381-1402. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Shang Song
- Department of Bioengineering and Therapeutic Sciences, University of California-San Francisco, San Francisco, California 94158
| | - Shuvo Roy
- Department of Bioengineering and Therapeutic Sciences, University of California-San Francisco, San Francisco, California 94158.
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14
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Humpel C. Organotypic brain slice cultures: A review. Neuroscience 2015; 305:86-98. [PMID: 26254240 PMCID: PMC4699268 DOI: 10.1016/j.neuroscience.2015.07.086] [Citation(s) in RCA: 266] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 07/24/2015] [Accepted: 07/31/2015] [Indexed: 12/27/2022]
Abstract
In vitro cell cultures are an important tool for obtaining insights into cellular processes in an isolated system and a supplement to in vivo animal experiments. While primary dissociated cultures permit a single homogeneous cell population to be studied, there is a clear need to explore the function of brain cells in a three-dimensional system where the main architecture of the cells is preserved. Thus, organotypic brain slice cultures have proven to be very useful in investigating cellular and molecular processes of the brain in vitro. This review summarizes (1) the historical development of organotypic brain slices focusing on the membrane technology, (2) methodological aspects regarding culturing procedures, age of donors or media, (3) whether the cholinergic neurons serve as a model of neurodegeneration in Alzheimer’s disease, (4) or the nigrostriatal dopaminergic neurons as a model of Parkinson’s disease and (5) how the vascular network can be studied, especially with regard to a synthetic blood–brain barrier. This review will also highlight some limits of the model and give an outlook on future applications.
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Affiliation(s)
- C Humpel
- Laboratory of Psychiatry and Experimental Alzheimer's Research, Department of Psychiatry and Psychotherapy, Medical University of Innsbruck, Anichstrasse 35, A-6020 Innsbruck, Austria.
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Abstract
Organotypic hippocampal slice cultures (OHSCs) have been used as a powerful ex vivo model for decades. They have been used successfully in studies of neuronal death, microglial activation, mossy fiber regeneration, neurogenesis, and drug screening. As a pre-animal experimental phase for physiologic and pathologic brain research, OHSCs offer outcomes that are relatively closer to those of whole-animal studies than outcomes obtained from cell culture in vitro. At the same time, mechanisms can be studied more precisely in OHSCs than they can be in vivo. Here, we summarize stroke and traumatic brain injury research that has been carried out in OHSCs and review classic experimental applications of OHSCs and its limitations.
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Bosca A, Martina M, Py C. Planar patch clamp for neuronal networks--considerations and future perspectives. Methods Mol Biol 2014; 1183:93-113. [PMID: 25023304 DOI: 10.1007/978-1-4939-1096-0_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The patch-clamp technique is generally accepted as the gold standard for studying ion channel activity allowing investigators to either "clamp" membrane voltage and directly measure transmembrane currents through ion channels, or to passively monitor spontaneously occurring intracellular voltage oscillations. However, this resulting high information content comes at a price. The technique is labor-intensive and requires highly trained personnel and expensive equipment. This seriously limits its application as an interrogation tool for drug development. Patch-clamp chips have been developed in the last decade to overcome the tedious manipulations associated with the use of glass pipettes in conventional patch-clamp experiments. In this chapter, we describe some of the main materials and fabrication protocols that have been developed to date for the production of patch-clamp chips. We also present the concept of a patch-clamp chip array providing high resolution patch-clamp recordings from individual cells at multiple sites in a network of communicating neurons. On this chip, the neurons are aligned with the aperture-probes using chemical patterning. In the discussion we review the potential use of this technology for pharmaceutical assays, neuronal physiology and synaptic plasticity studies.
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Affiliation(s)
- Alessandro Bosca
- Italian Institute of Technology, Via Morego 30, 16163, Genoa, Italy,
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Albus K, Heinemann U, Kovács R. Network activity in hippocampal slice cultures revealed by long-term in vitro recordings. J Neurosci Methods 2013; 217:1-8. [PMID: 23639918 DOI: 10.1016/j.jneumeth.2013.04.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 03/21/2013] [Accepted: 04/16/2013] [Indexed: 01/19/2023]
Abstract
Organotypic hippocampal slice cultures (OHSCs) are widely used for anatomical, molecular and electrophysiological studies of the development of neuronal networks. Electrophysiological recordings are usually limited to a single time point during development, and recording conditions differ greatly based on culture conditions. Consequently, little is known about the maturation of neuronal network activity in vitro. Here, we describe a simple method that allows long-term electrophysiological recordings during culture maintenance in a CO2 incubator. We compared the occurrence of spontaneous network activity, including epileptiform activity, in OHSCs (maintained in Neurobasal/B27 serum-free medium) prepared at different postnatal days and investigated the effects of changes in osmolality and pH. Recordings over 48 h revealed spontaneous network activity culminating in seizure-like events (SLEs) in 65.4% of the OHSCs (n=78). SLE incidence peaked during the first 6h following implantation of the microelectrodes and a secondary increase in SLE-incidence began after 9h of recording and averaged 2.65SLEs/h. The initial peak was likely initiated by transient alkalosis induced by the low pCO2 during the positioning of the electrodes, whereas successive changes in the composition of the culture medium might explain the secondary increase in SLE incidence. Notably, changes in osmolality had no effect on SLE induction. In conclusion, long-term recordings in OHSCs will help to reveal changes in spontaneous network activity during maturation. The extent to which the axonal reorganization known to occur in OHSCs contributes to the susceptibility to epileptogenesis remains to be determined.
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Affiliation(s)
- Klaus Albus
- Institute of Neurophysiology, Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany.
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18
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Bal BS, Rahaman MN. Orthopedic applications of silicon nitride ceramics. Acta Biomater 2012; 8:2889-98. [PMID: 22542731 DOI: 10.1016/j.actbio.2012.04.031] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 04/18/2012] [Accepted: 04/19/2012] [Indexed: 11/29/2022]
Abstract
Silicon nitride (Si(3)N(4)) is a ceramic material developed for industrial applications that demand high strength and fracture resistance under extreme operating conditions. Recently, Si(3)N(4) has been used as an orthopedic biomaterial, to promote bone fusion in spinal surgery and to develop bearings that can improve the wear and longevity of prosthetic hip and knee joints. Si(3)N(4) has been implanted in human patients for over 3 years now, and clinical trials with Si(3)N(4) femoral heads in prosthetic hip replacement are contemplated. This review will provide background information and data relating to Si(3)N(4) ceramics that will be of interest to engineering and medical professionals.
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Affiliation(s)
- B S Bal
- Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, MO 65211, USA.
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19
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Anselmi F, Bertherat J, Estebanez L, van 't Hoff M, Zylbersztejn K. An interdisciplinary learning experience in neuro-optics. ACTA ACUST UNITED AC 2012; 106:58-61. [PMID: 22321445 DOI: 10.1016/j.jphysparis.2012.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 01/24/2012] [Accepted: 01/24/2012] [Indexed: 11/27/2022]
Abstract
How can a Ph.D. student initially trained as a biologist take part in the development of a multineuronal recording method that requires cross interaction between physics, neurobiology and mathematics? Beyond student training in the laboratory, interdisciplinary research calls for a new style of academic training of young researchers. Here we present an innovative approach to graduate student academic training that fills the need for multidisciplinary knowledge and provides students, in addition, with a deeper understanding of the interdisciplinary approach to scientific research.
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Affiliation(s)
- Francesca Anselmi
- Frontiers in Life Sciences, Université Paris Descartes - Université Paris Diderot, France
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20
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Nørregaard A, Jensen SS, Kolenda J, Aaberg-Jessen C, Christensen KG, Jensen PH, Schrøder HD, Kristensen BW. Effects of Chemotherapeutics on Organotypic Corticostriatal Slice Cultures Identified by A Panel of Fluorescent and Immunohistochemical Markers. Neurotox Res 2011; 22:43-58. [DOI: 10.1007/s12640-011-9300-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 12/05/2011] [Accepted: 12/06/2011] [Indexed: 11/29/2022]
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Maccione A, Gandolfo M, Tedesco M, Nieus T, Imfeld K, Martinoia S, Berdondini L. Experimental Investigation on Spontaneously Active Hippocampal Cultures Recorded by Means of High-Density MEAs: Analysis of the Spatial Resolution Effects. FRONTIERS IN NEUROENGINEERING 2010; 3:4. [PMID: 20485465 PMCID: PMC2871691 DOI: 10.3389/fneng.2010.00004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 04/06/2010] [Indexed: 11/14/2022]
Abstract
Based on experiments performed with high-resolution Active Pixel Sensor microelectrode arrays (APS-MEAs) coupled with spontaneously active hippocampal cultures, this work investigates the spatial resolution effects of the neuroelectronic interface on the analysis of the recorded electrophysiological signals. The adopted methodology consists, first, in recording the spontaneous activity at the highest spatial resolution (interelectrode separation of 21 μm) from the whole array of 4096 microelectrodes. Then, the full resolution dataset is spatially downsampled in order to evaluate the effects on raster plot representation, array-wide spike rate (AWSR), mean firing rate (MFR) and mean bursting rate (MBR). Furthermore, the effects of the array-to-network relative position are evaluated by shifting a subset of equally spaced electrodes on the entire recorded area. Results highlight that MFR and MBR are particularly influenced by the spatial resolution provided by the neuroelectronic interface. On high-resolution large MEAs, such analysis better represent the time-based parameterization of the network dynamics. Finally, this work suggest interesting capabilities of high-resolution MEAs for spatial-based analysis in dense and low-dense neuronal preparation for investigating signaling at both local and global neuronal circuitries.
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Affiliation(s)
- Alessandro Maccione
- Neuroscience and Brain Technologies, Italian Institute of Technology Genova, Italy
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22
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Abstract
Sepsis is often complicated by an acute and reversible deterioration of mental status, which is associated with increased mortality and is consistent with delirium but can also be revealed by a focal neurologic sign. Sepsis-associated encephalopathy is accompanied by abnormalities of electroencephalogram and somatosensory-evoked potentials, increased in biomarkers of brain injury (i.e., neuron-specific enolase, S-100 beta-protein) and, frequently, by neuroradiological abnormalities, notably leukoencephalopathy. Its mechanism is highly complex, resulting from both inflammatory and noninflammatory processes that affect all brain cells and induce blood-brain barrier breakdown, dysfunction of intracellular metabolism, brain cell death, and brain injuries. Its diagnosis relies essentially on neurologic examination that can lead one to perform specific neurologic tests. Electroencephalography is required in the presence of seizure; neuroimaging in the presence of seizure, focal neurologic signs or suspicion of cerebral infection; and both when encephalopathy remains unexplained. In practice, cerebrospinal fluid analysis should be performed if there is any doubt of meningitis. Hepatic, uremic, or respiratory encephalopathy, metabolic disturbances, drug overdose, withdrawal of sedatives or opioids, alcohol withdrawal delirium, and Wernicke's encephalopathy are the main differential diagnoses of sepsis-associated encephalopathy. Patient management is based mainly on controlling infection, organ system failure, and metabolic homeostasis, at the same time avoiding neurotoxic drugs.
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Charrier A, Martinez D, Monette R, Comas T, Movileanu R, Py C, Denhoff M, Krantis A, Mealing G. Cell placement and guidance on substrates for neurochip interfaces. Biotechnol Bioeng 2010; 105:368-73. [DOI: 10.1002/bit.22539] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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24
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The Electrochemistry of Charge Injection at the Electrode/Tissue Interface. IMPLANTABLE NEURAL PROSTHESES 2 2010. [DOI: 10.1007/978-0-387-98120-8_4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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25
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The effect of ultra-nanocrystalline diamond films on the proliferation and differentiation of neural stem cells. Biomaterials 2009; 30:3428-35. [DOI: 10.1016/j.biomaterials.2009.03.058] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 03/04/2009] [Indexed: 12/20/2022]
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Bakota L, Brandt R. Chapter 2 Live‐Cell Imaging in the Study of Neurodegeneration. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 276:49-103. [DOI: 10.1016/s1937-6448(09)76002-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Microfluidics and multielectrode array-compatible organotypic slice culture method. J Neurosci Methods 2008; 178:59-64. [PMID: 19100768 DOI: 10.1016/j.jneumeth.2008.11.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Revised: 11/13/2008] [Accepted: 11/14/2008] [Indexed: 01/09/2023]
Abstract
Organotypic brain slice cultures are used for a variety of molecular, electrophysiological, and imaging studies. However, the existing culture methods are difficult or expensive to apply in studies requiring long-term recordings with multielectrode arrays (MEAs). In this work, a novel method to maintain organotypic cultures of rodent hippocampus for several weeks on standard MEAs in an unmodified tissue culture incubator is described. Polydimethylsiloxane (Sylgard) mini-wells were used to stabilize organotypic cultures on glass and MEA surfaces. Hippocampus slices were successfully maintained within PDMS mini-wells for multiple weeks, with preserved pyramidal layer organization, connectivity, and activity. MEAs were used to record the development of spontaneous activity in an organotypic cultures for 4 weeks. This method is compatible with integration of microchannels into the culture substrate. Microchannels were incorporated into the mini-wells and applied to the guidance of axons originating within the slice, paving the way for studies of axonal sprouting using organotypic slices.
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Mazzocchi M, Bellosi A. On the possibility of silicon nitride as a ceramic for structural orthopaedic implants. Part I: processing, microstructure, mechanical properties, cytotoxicity. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:2881-2887. [PMID: 18347952 DOI: 10.1007/s10856-008-3417-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Accepted: 02/26/2008] [Indexed: 05/26/2023]
Abstract
Notwithstanding the good combination of mechanical and tribological properties, the suitability of silicon nitride for application as prosthesis in bone reconstruction or in articular joints replacements is still controversial. This study aims to design and produce three different silicon nitride-based ceramics and to test the materials. In this Part I the microstructure and mechanical properties evidence outstanding characteristics and the cytotoxicity studies confirm that all the materials are extremely inert and biocompatible. In Part II, the wear performance and the wettability and chemical stability against different aqueous media and physiological solutions are investigated and discussed.
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Affiliation(s)
- Mauro Mazzocchi
- Institute for Sciences and Technology for Ceramics, National Research Council, Via Granarolo, n.64, Faenza, Ravenna 48018, Italy.
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Chang WC, Hawkes EA, Kliot M, Sretavan DW. In vivo use of a nanoknife for axon microsurgery. Neurosurgery 2007; 61:683-91; discussion 691-2. [PMID: 17986929 DOI: 10.1227/01.neu.0000298896.31355.80] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE Microfabricated devices with nanoscale features have been proposed as new microinstrumentation for cellular and subcellular surgical procedures, but their effectiveness in vivo has yet to be demonstrated. In this study, we examined the in vivo use of 10 to 100 microm-long nanoknives with cutting edges of 20 nm in radius of curvature during peripheral nerve surgery. METHODS Peripheral nerves from anesthetized mice were isolated on a rudimentary microplatform with stimulation microelectrodes, and the nanoknives were positioned by a standard micromanipulator. The surgical field was viewed through a research microscope system with brightfield and fluorescence capabilities. RESULTS Using this assembly, the nanoknife effectively made small, 50 to 100 microm-long incisions in nerve tissue in vivo. This microfabricated device was also robust enough to make repeated incisions to progressively pare down the nerve as documented visually and by the accompanying incremental diminution of evoked motor responses recorded from target muscle. Furthermore, this nanoknife also enabled the surgeon to perform procedures at an unprecedented small scale such as the cutting and isolation of a small segment from a single constituent axon in a peripheral nerve in vivo. Lastly, the nanoknife material (silicon nitride) did not elicit any acute neurotoxicity as evidenced by the robust growth of axons and neurons on this material in vitro. CONCLUSION Together, these demonstrations support the concept that microdevices deployed in a neurosurgical environment in vivo can enable novel procedures at an unprecedented small scale. These devices are potentially the vanguard of a new family of microscale instrumentation that can extend surgical procedures down to the cellular scale and beyond.
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Affiliation(s)
- Wesley C Chang
- Department of Ophthalmology, University of California, San Francisco, California 94143, USA.
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30
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Yu Z, McKnight TE, Ericson MN, Melechko AV, Simpson ML, Morrison B. Vertically aligned carbon nanofiber arrays record electrophysiological signals from hippocampal slices. NANO LETTERS 2007; 7:2188-95. [PMID: 17604402 DOI: 10.1021/nl070291a] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Vertically aligned carbon nanofiber (VACNF) electrode arrays were tested for their potential application in recording neuro-electrophysiological activity. We report, for the first time, stimulation and extracellular recording of spontaneous and evoked neuroelectrical activity in organotypic hippocampal slice cultures with ultramicroelectrode VACNF arrays. Because the electrodes are carbon-based, these arrays have potential advantages over metal electrodes and could enable a variety of future applications as precise, informative, and biocompatible neural interfaces.
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Affiliation(s)
- Zhe Yu
- Department of Biomedical Engineering, Columbia University, 1210 Amsterdam Avenue, 351 Engineering Terrace, New York, New York 10027, USA
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31
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Wang A, Liang X, McAllister JP, Li J, Brabant K, Black C, Finlayson P, Cao T, Tang H, Salley SO, Auner GW, Simon Ng KY. Stability of and inflammatory response to silicon coated with a fluoroalkyl self-assembled monolayer in the central nervous system. J Biomed Mater Res A 2007; 81:363-72. [PMID: 17117466 DOI: 10.1002/jbm.a.31034] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A self-assembled monolayer (SAM) of fluoroalkyl silane (FAS) (CF(3)(CF(2))(5)(CH(2))(2)SiCl(3)) was deposited on the surface of silicon wafers, aiming to enhance its stability and to reduce the inflammatory response in the central nervous system. Following implantation of the FAS SAM coated silicon in rat brains, the FAS SAM coating failed to reduce the inflammatory response of silicon, because it could not prevent the corrosion of the underlying silicon. The corrosion was hindered for the initial 10 days by the FAS SAM coating, but there was nearly no difference when compared to the uncoated silicon when the implantation periods were extended to 28 and 90 days. The FAS SAM coating was completely removed within 28 and 90 days. Meanwhile, on all the extracted uncoated and FAS SAM coated silicon wafers, there were proteinaceous substances deposited on the surfaces, and the amount of the deposits increased with exposure time.
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Affiliation(s)
- Anfeng Wang
- Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Drive, Detroit, Michigan 48202, USA
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Cui HF, Ye JS, Chen Y, Chong SC, Sheu FS. Microelectrode array biochip: tool for in vitro drug screening based on the detection of a drug effect on dopamine release from PC12 cells. Anal Chem 2007; 78:6347-55. [PMID: 16970308 DOI: 10.1021/ac060018d] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Novel, yet simple detection techniques of drug effect, including the effect of a vesicular monoamine transporter inhibitor (reserpine), a dopamine precursor (L-dopa), and a dopamine transporter inhibitor (nomifensine), on dopamine release from dopaminergic PC12 cells were developed based on a microelectrode array (MEA) biochip. Upon multi-injections of KCl solution into the culture of PC12 cells attached on a MEA biochip, the K+-stimulated dopamine release was temporally and amperometrically recorded by biochip microelectrodes. Two parameters in the recorded amperometric spectra were defined in this study: the peak current of the first KCl injection (Max1), and the steady current after the fourth KCl injection (St4). Statistically significant effects of L-dopa and reserpine were demonstrated by comparing both Max1 and St4 of the second detections in drugs with those of the control without drug treatment. The values of both Max1 and St4 in the first detections were normalized as 1. In contrast, the statistically significant effect of nomifensine was detected by comparing the ratios of St4 to Max1 in the first detections in drug with those of the control. The reason for using different analytical methods for measurements between L-dopa/reserpine and nomifensine lies in the different mechanisms of action on PC12 cells among these drugs. The novel analytical methods developed use the same detection setup and parameters, and the data analysis for the effect of drugs becomes simple. The methods hence may provide a high-throughput in vitro drug screening approach for dopamine-related psychiatric disorders.
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Affiliation(s)
- Hui-Fang Cui
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
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33
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Harry GJ, Tiffany-Castiglioni E. Evaluation of neurotoxic potential by use of in vitro systems. Expert Opin Drug Metab Toxicol 2006; 1:701-13. [PMID: 16863434 DOI: 10.1517/17425255.1.4.701] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In vitro systems have been proposed, but not yet demonstrated, as a method to assess the neurotoxicity of compounds in an efficient and rapid manner. Although such tests are desired both for pharmaceuticals and environmental agents, such a battery has yet to be developed that is based on known processes of nervous system dysfunction. In this review article, characteristics and potential limitations associated with in vitro methods are discussed. Many of these features have been identified from a larger body of work examining the neurotoxicity of environmental agents and the mechanisms underlying activity of known neurotoxicants. These issues include relevant drug concentrations, factors that limit or alter drug accessibility to the nervous system, and the need for assays to reflect biologically meaningful end points. This commentary briefly surveys in vitro systems of increasing biological complexity currently available for toxicity testing, from single cell types to systems that preserve some aspects of tissue structure and function. A small number of studies to evaluate drugs for cytotoxicity and biological responses in vitro are presented as representative of the current state of the field and to provide a reference and direction for additional development of methods to assess a compound's potential for neurotoxicity.
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Affiliation(s)
- Gaylia Jean Harry
- National Institutes of Health, Laboratory of Neurobiology, National Institute of Environmental Health Sciences, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
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Krause G, Lehmann S, Lehmann M, Freund I, Schreiber E, Baumann W. Measurement of electrical activity of long-term mammalian neuronal networks on semiconductor neurosensor chips and comparison with conventional microelectrode arrays. Biosens Bioelectron 2006; 21:1272-82. [PMID: 16006112 DOI: 10.1016/j.bios.2005.05.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 05/27/2005] [Accepted: 05/31/2005] [Indexed: 11/19/2022]
Abstract
Based on complementary metal-oxide semiconductor (CMOS) technology a neurosensor chip with passive palladium electrodes was developed. The CMOS technology allows a high reproducibility of the sensors as well as miniaturization and the on-chip integration of electronics. Networks of primary neurones were taken from murine foetal spinal cord (day 14) and frontal cortex (day 15) tissues and cultured on the silicon surface in a chamber volume of 200 microl with 7 mm diameter. Measurements were performed between days 15 and 59 in vitro. Signals were recorded from both types of cultures. To test the capability of the system to detect pharmacologically induced activity changes two established neuromodulators were applied. The GABA(A)-receptor blocker bicuculline was applied to both tissue cultures, the glycine-receptor blocker strychnine to spinal cord cultures. Four network frequency parameters were analysed: spike rate (SR), burst rate (BR), frequency in bursts (FiB) and peak frequency in bursts (PFiB). Significant changes of spike rate and burst rate were measured with spinal cord cultures after bicuculline application. Significant changes of frequency in bursts and peak frequency in bursts were observed with frontal cortex cultures after bicuculline application. Significant changes of spike rate and frequency in bursts were recorded with spinal cord cultures after strychnine application. These results were compared with results achieved in the same laboratory by using glass-microelectrode arrays (MEAs). This comparison showed for spinal cord similar native spike and burst rate, but higher mean frequency and peak frequency in bursts, whereas frontal cortex activity had higher spike and burst rate and peak frequency in bursts. Application of bicuculline or strychnine to spinal cord networks showed stronger effects on MEAs, whereas with frontal cortex networks the modulation of activity was similar after application of bicuculline.
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Affiliation(s)
- Guido Krause
- Universität Rostock, Institut für Zellbiologie und Biosystemtechnik, Rostock, Germany
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Polikov VS, Tresco PA, Reichert WM. Response of brain tissue to chronically implanted neural electrodes. J Neurosci Methods 2005; 148:1-18. [PMID: 16198003 DOI: 10.1016/j.jneumeth.2005.08.015] [Citation(s) in RCA: 1092] [Impact Index Per Article: 57.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 08/06/2005] [Accepted: 08/08/2005] [Indexed: 11/16/2022]
Abstract
Chronically implanted recording electrode arrays linked to prosthetics have the potential to make positive impacts on patients suffering from full or partial paralysis. Such arrays are implanted into the patient's cortical tissue and record extracellular potentials from nearby neurons, allowing the information encoded by the neuronal discharges to control external devices. While such systems perform well during acute recordings, they often fail to function reliably in clinically relevant chronic settings. Available evidence suggests that a major failure mode of electrode arrays is the brain tissue reaction against these implants, making the biocompatibility of implanted electrodes a primary concern in device design. This review presents the biological components and time course of the acute and chronic tissue reaction in brain tissue, analyses the brain tissue response of current electrode systems, and comments on the various material science and bioactive strategies undertaken by electrode designers to enhance electrode performance.
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Affiliation(s)
- Vadim S Polikov
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
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36
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Merrill DR, Bikson M, Jefferys JGR. Electrical stimulation of excitable tissue: design of efficacious and safe protocols. J Neurosci Methods 2005; 141:171-98. [PMID: 15661300 DOI: 10.1016/j.jneumeth.2004.10.020] [Citation(s) in RCA: 1084] [Impact Index Per Article: 57.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2004] [Indexed: 11/26/2022]
Abstract
The physical basis for electrical stimulation of excitable tissue, as used by electrophysiological researchers and clinicians in functional electrical stimulation, is presented with emphasis on the fundamental mechanisms of charge injection at the electrode/tissue interface. Faradaic and non-Faradaic charge transfer mechanisms are presented and contrasted. An electrical model of the electrode/tissue interface is given. The physical basis for the origin of electrode potentials is given. Various methods of controlling charge delivery during pulsing are presented. Electrochemical reversibility is discussed. Commonly used electrode materials and stimulation protocols are reviewed in terms of stimulation efficacy and safety. Principles of stimulation of excitable tissue are reviewed with emphasis on efficacy and safety. Mechanisms of damage to tissue and the electrode are reviewed.
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Affiliation(s)
- Daniel R Merrill
- Department of Bioengineering, University of Utah, 20 South 2030 East, Biomedical Polymers Research Building, Room 108G, Salt Lake City, UT 84112-9458, USA.
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Ma SH, Lepak LA, Hussain RJ, Shain W, Shuler ML. An endothelial and astrocyte co-culture model of the blood-brain barrier utilizing an ultra-thin, nanofabricated silicon nitride membrane. LAB ON A CHIP 2005; 5:74-85. [PMID: 15616743 DOI: 10.1039/b405713a] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The endothelial cells comprising brain capillaries have extremely tight intercellular junctions which form an essentially impermeable barrier to passive transport of water soluble molecules between the blood and brain. Several in vitro models of the blood-brain barrier (BBB) have been studied, most utilizing commercially available polymer membranes affixed to plastic inserts. There is mounting evidence that direct contact between endothelial cells and astrocytes, another cell type found to have intimate interaction with the brain side of BBB capillaries, is at least partially responsible for the development of the tight intercellular junctions between BBB endothelial cells. However, the membranes commonly used for BBB in vitro models are lacking certain attributes that would permit a high degree of direct contact between astrocytes and endothelial cells cultured on opposing sides. This work is based on the hypothesis that co-culturing endothelial and astrocyte cells on opposite sides of an ultra-thin, highly porous membrane will allow for increased direct interaction between the two cell types and therefore result in a better model of the BBB. We used standard nanofabrication techniques to make membranes from low-stress silicon nitride that are at least an order of magnitude thinner and at least two times more porous than commercial membrane inserts. An experimental survey of pore sizes for the silicon nitride membranes suggested pores approximately 400 nm in diameter are adequate for restricting astrocyte cell bodies to the seeded side while allowing astrocyte processes to pass through the pores and interact with endothelial cells on the opposite side. The inclusion of a spun-on, cross-linked collagen membrane allowed for astrocyte attachment and culture on the membranes for over two weeks. Astrocytes and endothelial cells displayed markers specific to their cell types when grown on the silicon nitride membranes. The transendothelial electrical resistances, a measure of barrier tightness, of endothelial and astrocyte co-cultures on the silicon nitride membranes were comparable to the commercial membranes, but neither system showed synergy between the two cell types in forming a tighter barrier. This lack of synergy may have been due to the loss of ability of commercially available primary bovine brain microvascular endothelial cells to respond to astrocyte differentiating signals.
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Affiliation(s)
- Sarina Harris Ma
- Dept. of Chemical and Biomolecular Engineering, Cornell University, 270 Olin Hall, Ithaca, NY 14853, USA
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Vince V, Thil MA, Veraart C, Colin IM, Delbeke J. Biocompatibility of platinum-metallized silicone rubber: in vivo and in vitro evaluation. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2004; 15:173-88. [PMID: 15109096 DOI: 10.1163/156856204322793566] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Silicone rubber is commonly used for biomedical applications, including implanted cuff electrodes for both recording and stimulation of peripheral nerves. This study was undertaken to evaluate the consequences of a new platinum metallization method on the biocompatibility of silicone rubber cuff electrodes. This method was introduced in order to allow the manufacture of spiral nerve cuff electrodes with a large number of contacts. The metallization process, implying silicone coating with poly(methyl methacrylate) (PMMA), its activation by an excimer laser and subsequent electroless metal deposition, led to a new surface microtexture. The neutral red cytotoxicity assay procedure was first applied in vitro on BALB/c 3T3 fibroblasts in order to analyze the cellular response elicited by the studied material. An in vivo assay was then performed to investigate the tissue reaction after chronic subcutaneous implantation of the metallized material. Results demonstrate that silicone rubber biocompatibility is not altered by the new platinum metallization method.
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Affiliation(s)
- V Vince
- Neural Rehabilitation Engineering Laboratory, Université catholique de Louvain, Faculty of Medicine, Department of Physiology and Pharmacology, Avenue Hippocrate 54, B-1200 Brussels, Belgium
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Koeneman BA, Lee KK, Singh A, He J, Raupp GB, Panitch A, Capco DG. An ex vivo method for evaluating the biocompatibility of neural electrodes in rat brain slice cultures. J Neurosci Methods 2004; 137:257-63. [PMID: 15262069 DOI: 10.1016/j.jneumeth.2004.02.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2003] [Revised: 02/25/2004] [Accepted: 02/26/2004] [Indexed: 11/15/2022]
Abstract
Failure of neural recording electrodes implanted in the brain is often attributed to the formation of glial scars around the implant. A leading cause of scar formation is the electrode material. Described below is an approach to evaluate the biocompatibility of novel electrode materials in a representative three-dimensional model. The model, brain slice culture, accounts for the response of the neural tissue in the absence of the systemic response. While limitations of any in vitro model exist, brain slice culture provides an indication of the response of neurons and glia in an environment more indicative of the in vivo environment than two-dimensional cell culture of glia or neurons alone. Polybenzylcyclobutene (BCB) electrodes were developed as test materials for flexible electrodes due to ease of processing, low water uptake, and inherent flexibility when formed in thin sheets. Biocompatibilty of the BCB neural electrodes was evaluated using living brain slices derived from the hippocampal regions of 100 g CD rats. Importantly, fewer animals can be used in brain slice culture to evaluate the neural tissue response than when using live animals, since several slices can be obtained per animal. Cellular response to the electrodes was evaluated at 0, 7, and 14 days. At all time points living cells, both neurons and glia, were observed in the vicinity of the electrode. In addition, cells were observed migrating out from the brain slices onto the shank of the BCB electrode. Brain slice culture is shown to be a viable alternative to in vivo evaluation, in that the response of both neurons and glia can be evaluated in a native three-dimensional state, while sacrificing fewer animals. Future in vivo evaluation with BCB will provide definitive answers on the degree of glial scarring in response to this new and biocompatible electrode material.
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Affiliation(s)
- Brian A Koeneman
- Cellular and Molecular Biosciences Faculty, School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
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Pizzi M, Sarnico I, Boroni F, Benarese M, Dreano M, Garotta G, Valerio A, Spano P. Prevention of neuron and oligodendrocyte degeneration by interleukin-6 (IL-6) and IL-6 receptor/IL-6 fusion protein in organotypic hippocampal slices. Mol Cell Neurosci 2004; 25:301-11. [PMID: 15019946 DOI: 10.1016/j.mcn.2003.10.022] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2003] [Revised: 10/20/2003] [Accepted: 10/31/2003] [Indexed: 11/16/2022] Open
Abstract
We investigated the effects of IL-6 and a chimeric derivative of IL-6 and soluble IL-6 receptor (IL6RIL6 chimera) on excitotoxic injury in rat organotypic hippocampal slices. Brief application of N-methyl-d-aspartate (NMDA) induced astrocyte reactivity, neuron cell death, and oligodendrocyte degeneration, the latter caused by secondary activation of AMPA/kainate receptors. Both these cytokines rescued neurons and oligodendrocytes, albeit the chimeric compound was much more potent and efficient than IL-6. No change was produced on reactive astrocytosis. The cytokines preserved myelin basic protein (MBP) production in slices exposed to excitotoxic insult, and when applied singularly for a week, they also enhanced both MBP and proteolipid protein expression. These effects occurred through activating the signal transducer gp130 and were associated with stimulation of transcription factors STAT1 and STAT3. Our results suggest that IL-6 and IL6RIL6 may prove to be valuable in treating neurodegenerative and demyelinating diseases.
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Affiliation(s)
- Marina Pizzi
- Department of Biomedical Sciences and Biotechnologies, University of Brescia, 25123 Brescia, Italy.
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Smith SL, Judy JW, Otis TS. An ultra small array of electrodes for stimulating multiple inputs into a single neuron. J Neurosci Methods 2004; 133:109-14. [PMID: 14757351 DOI: 10.1016/j.jneumeth.2003.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have developed an ultra small, translucent array of electrodes for use in the parasaggital cerebellar slice preparation. This positionable array is capable of stimulating multiple independent bundles of parallel fibers (PFs), which synapse onto a single Purkinje neuron. On a silicon substrate, a low-stress silicon nitride film was used both as a structural layer and as electrical insulation. Evaporated gold pads and interconnects were sandwiched between two such layers. A bulk anisotropic silicon etch released the individual arrays. The electrodes are supported within a 2-microm-thick cantilever of translucent silicon nitride. In one design, eight 4-microm-wide square electrodes are arranged on 8-microm-centers. Another design, half the scale of the first, was also tested. The array was mounted on a micromanipulator and can be visualized by an upright microscope. It can then be positioned in the dendritic arbor of a Purkinje neuron while not disturbing a recording pipette at the soma. Paired-pulse facilitation experiments have confirmed that the electrodes are capable of stimulating non-overlapping bundles of PFs. This device will be useful for exploring spatiotemporal synaptic integration in single neurons. Potential applications in experiments on cerebellar LTD are also discussed.
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Affiliation(s)
- Spencer L Smith
- Neuroscience and Neuroengineering Programs, 1320 Gonda Center, 695 Young Drive South, University of California, Los Angeles, CA 90095, USA.
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Csicsvari J, Henze DA, Jamieson B, Harris KD, Sirota A, Barthó P, Wise KD, Buzsáki G. Massively parallel recording of unit and local field potentials with silicon-based electrodes. J Neurophysiol 2003; 90:1314-23. [PMID: 12904510 DOI: 10.1152/jn.00116.2003] [Citation(s) in RCA: 250] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Parallel recording of neuronal activity in the behaving animal is a prerequisite for our understanding of neuronal representation and storage of information. Here we describe the development of micro-machined silicon microelectrode arrays for unit and local field recordings. The two-dimensional probes with 96 or 64 recording sites provided high-density recording of unit and field activity with minimal tissue displacement or damage. The on-chip active circuit eliminated movement and other artifacts and greatly reduced the weight of the headgear. The precise geometry of the recording tips allowed for the estimation of the spatial location of the recorded neurons and for high-resolution estimation of extracellular current source density. Action potentials could be simultaneously recorded from the soma and dendrites of the same neurons. Silicon technology is a promising approach for high-density, high-resolution sampling of neuronal activity in both basic research and prosthetic devices.
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Affiliation(s)
- Jozsef Csicsvari
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, Newark, New Jersey 07102, USA
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Voskerician G, Shive MS, Shawgo RS, von Recum H, Anderson JM, Cima MJ, Langer R. Biocompatibility and biofouling of MEMS drug delivery devices. Biomaterials 2003; 24:1959-67. [PMID: 12615486 DOI: 10.1016/s0142-9612(02)00565-3] [Citation(s) in RCA: 430] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The biocompatibility and biofouling of the microfabrication materials for a MEMS drug delivery device have been evaluated. The in vivo inflammatory and wound healing response of MEMS drug delivery component materials, metallic gold, silicon nitride, silicon dioxide, silicon, and SU-8(TM) photoresist, were evaluated using the cage implant system. Materials, placed into stainless-steel cages, were implanted subcutaneously in a rodent model. Exudates within the cage were sampled at 4, 7, 14, and 21 days, representative of the stages of the inflammatory response, and leukocyte concentrations (leukocytes/microl) were measured. Overall, the inflammatory responses elicited by these materials were not significantly different than those for the empty cage controls over the duration of the study. The material surface cell density (macrophages or foreign body giant cells, FBGCs), an indicator of in vivo biofouling, was determined by scanning electron microscopy of materials explanted at 4, 7, 14, and 21 days. The adherent cellular density of gold, silicon nitride, silicon dioxide, and SU-8(TM) were comparable and statistically less (p<0.05) than silicon. These analyses identified the MEMS component materials, gold, silicon nitride, silicon dioxide, SU-8(TM), and silicon as biocompatible, with gold, silicon nitride, silicon dioxide, and SU-8(TM) showing reduced biofouling.
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Affiliation(s)
- Gabriela Voskerician
- Department of Biomedical Engineering, Institute of Pathology, Case Western Reserve University, 2085 Adelbert Road, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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Kristensen BW, Noer H, Gramsbergen JB, Zimmer J, Noraberg J. Colchicine induces apoptosis in organotypic hippocampal slice cultures. Brain Res 2003; 964:264-78. [PMID: 12576187 DOI: 10.1016/s0006-8993(02)04080-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The microtubule-disrupting agent colchicine is known to be particular toxic for certain types of neurons, including the granule cells of the dentate gyrus. In this study we investigated whether colchicine could induce such neuron-specific degeneration in developing (1 week in vitro) and mature (3 weeks in vitro) organotypic hippocampal slice cultures and whether the induced cell death was apoptotic and/or necrotic. When applied to 1-week-old cultures for 48 h, colchicine induced primarily apoptotic, but also a minor degree of necrotic cell death in the dentate granule cells, as investigated by cellular uptake of the fluorescent dye propidium iodide (PI), immunostaining for active caspase 3 and c-Jun/AP-1 (N) and fragmentation of nuclei as seen in Hoechst 33342 staining. All four markers appeared after 12 h of colchicine exposure. Two of them, active caspase 3 and c-Jun/AP-1 (N) displayed a similar time course and reached a maximum after 24 h of exposure, 24 h ahead of both PI uptake and Hoechst 33342 staining, which together displayed similar time profiles and a close correlation. In 3-week-old cultures, colchicine did not induce apoptotic or necrotic cell death. Attempts to interfere with the colchicine-induced apoptosis in 1-week-old cultures showed that colchicine-induced PI uptake and formation of apoptotic nuclei were temporarily prevented by coapplication of the protein synthesis inhibitor cycloheximide. Application of the pancaspase inhibitor z-VAD-fmk almost completely abolished the formation of active caspase 3 protein and apoptotic nuclei induced by colchicine, but the formation of necrotic nuclei increased correspondingly and the PI uptake was unaffected. We conclude that colchicine induces caspase 3-dependent apoptotic cell death of dentate granule cells in hippocampal brain slice cultures, but the apoptotic cell death is highly dependent on the developmental stage of the cultures.
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Affiliation(s)
- Bjarne W Kristensen
- Department of Anatomy and Neurobiology, Institute of Medical Biology, University of Southern Denmark, Winsløwparken 21, DK-5000 C, Odense, Denmark.
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Abstract
Technological advances in miniaturization have found a niche in biology and signal the beginning of a new revolution. Most of the attention and advances have been made with DNA chips yet a lot of progress is being made in the use of other biomolecules and cells. A variety of reviews have covered only different aspects and technologies but leading to the shared terminology of "biochips." This review provides a basic introduction and an in-depth survey of the different technologies and applications involving the use of non-DNA molecules such as proteins and cells. The review focuses on microarrays and microfluidics, but also describes some cellular systems (studies involving patterning and sensor chips) and nanotechnology. The principles of each technology including parameters involved in biochip design and operation are outlined. A discussion of the different biological and biomedical applications illustrates the significance of biochips in biotechnology.
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Affiliation(s)
- Jocelyn H Ng
- IMI Consulting GmbH, Auf dem Amtshof 3, 30938 Burgwedel, Germany.
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Graulich J, Hoffmann U, Maier RF, Ruscher K, Pomper JK, Ko HK, Gabriel S, Obladen M, Heinemann U. Acute neuronal injury after hypoxia is influenced by the reoxygenation mode in juvenile hippocampal slice cultures. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2002; 137:35-42. [PMID: 12128252 DOI: 10.1016/s0165-3806(02)00365-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In neonates asphyxia is usually followed by hyperoxia due to resuscitation procedures. In order to study whether hyperoxic reoxygenation might cause additional cell injury we subjected organotypic hippocampal slice cultures of juvenile rats to normoxic or hyperoxic reoxygenation (19 or 85% oxygen, respectively) following hypoxia (3% oxygen) for 30, 60, and 120 min. Cell injury was quantified by lactate dehydrogenase (LDH) release and propidium iodide (PI) fluorescence 1 h after end of the reoxygenation period. In both experimental groups, LDH activity was significantly enhanced by hypoxia as compared to normoxic controls. However, hyperoxic reoxygenation caused a larger increase in LDH activity than normoxic reoxygenation (e.g., by a factor of 1.60 vs. 1.29 following 120 min hypoxia). PI fluorescence increased after hypoxia in all principal cell layers of the hippocampus but again showed a larger enhancement after hyperoxic reoxygenation as compared to normoxic reoxygenation (e.g., by a factor of 3.9 vs. 1.7 for CA1 and 120 min of hypoxia). After normoxic reoxygenation, PI fluorescence intensity was lower in the dentate gyrus as compared to CA1 and CA3, while it reached similar values like CA1 after high oxygen supply. In conclusion, juvenile hippocampal slice cultures subjected to hyperoxic reoxygenation display a greater amount of acute neuronal injury than slice cultures undergoing normoxic reoxygenation.
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Affiliation(s)
- Johannes Graulich
- Charité, Humboldt University Berlin, Department of Neonatology, Augustenburger Platz 1, D-13353 Berlin, Germany
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Abstract
The development of microchips involving proteins has accelerated within the past few years. Although DNA chip technologies formed the precedent, many different strategies and technologies have been used because proteins are inherently a more complex type of molecule. This review covers the various biomedical applications of protein chips in diagnostics, drug screening and testing, disease monitoring, drug discovery (proteomics), and medical research. The proteomics and drug discovery section is further subdivided to cover drug discovery tools (on-chip separations, expression profiling, and antibody arrays), molecular interactions and signaling pathways, the identification of protein function, and the identification of novel therapeutic compounds. Although largely focused on protein chips, this review includes chips involving cells and tissues as a logical extension of the type of data that can be generated from these microchips.
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Affiliation(s)
- Jocelyn H Ng
- Xerion Pharmaceuticals AG, Martinsried, Germany.
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