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Li X, Chen Y, Tu X, Huang H. Development of a Three-Dimensional Nerve Stretch Growth Device towards an Implantable Neural Interface. MICROMACHINES 2022; 13:1558. [PMID: 36295911 PMCID: PMC9610007 DOI: 10.3390/mi13101558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/09/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Because of rising traumatic accidents and diseases, the number of patients suffering from nerve injury is increasing. Without effective rehabilitation therapy, the patients will get motor or sensory function losses or even a lifelong disability. As for amputees, neural interface technology can be used to splice nerves and electrical wires together in a way that allows them to control an artificial limb as if it was a natural extension of the body. However, the means the need for an autologous nerve to stimulate axonal regeneration and extension into target tissues, which are limited by the supply of donor nerves. Based on the principle of mechanical force regulating axon growth, in this paper, we developed a three-dimensional nerve stretch growth device for an implantable neural interface. The device consists of three motors controlled by single chip microcomputer and some mechanical parts. The stability and reliability of the device were tested. Then, we used neurons derived from human pluripotent stem cells by small chemical molecules to explore the optimal three-dimensional stretch culture parameters. Furthermore, we found that the axons were intact through 10 rotations per day and 1 mm of horizontal pulling per day. The results of this research will provide convenience for patients treated through an implantable neural interface.
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Affiliation(s)
- Xiao Li
- School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China
| | - Yongguang Chen
- School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China
| | - Xikai Tu
- School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China
| | - Hailong Huang
- Department of Rehabilitation Medicine, Zhongnan Hospital of Wuhan University, Wuhan 430077, China
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Habibey R, Rojo Arias JE, Striebel J, Busskamp V. Microfluidics for Neuronal Cell and Circuit Engineering. Chem Rev 2022; 122:14842-14880. [PMID: 36070858 PMCID: PMC9523714 DOI: 10.1021/acs.chemrev.2c00212] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The widespread adoption of microfluidic devices among the neuroscience and neurobiology communities has enabled addressing a broad range of questions at the molecular, cellular, circuit, and system levels. Here, we review biomedical engineering approaches that harness the power of microfluidics for bottom-up generation of neuronal cell types and for the assembly and analysis of neural circuits. Microfluidics-based approaches are instrumental to generate the knowledge necessary for the derivation of diverse neuronal cell types from human pluripotent stem cells, as they enable the isolation and subsequent examination of individual neurons of interest. Moreover, microfluidic devices allow to engineer neural circuits with specific orientations and directionality by providing control over neuronal cell polarity and permitting the isolation of axons in individual microchannels. Similarly, the use of microfluidic chips enables the construction not only of 2D but also of 3D brain, retinal, and peripheral nervous system model circuits. Such brain-on-a-chip and organoid-on-a-chip technologies are promising platforms for studying these organs as they closely recapitulate some aspects of in vivo biological processes. Microfluidic 3D neuronal models, together with 2D in vitro systems, are widely used in many applications ranging from drug development and toxicology studies to neurological disease modeling and personalized medicine. Altogether, microfluidics provide researchers with powerful systems that complement and partially replace animal models.
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Affiliation(s)
- Rouhollah Habibey
- Department of Ophthalmology, Universitäts-Augenklinik Bonn, University of Bonn, Ernst-Abbe-Straße 2, D-53127 Bonn, Germany
| | - Jesús Eduardo Rojo Arias
- Wellcome─MRC Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, United Kingdom
| | - Johannes Striebel
- Department of Ophthalmology, Universitäts-Augenklinik Bonn, University of Bonn, Ernst-Abbe-Straße 2, D-53127 Bonn, Germany
| | - Volker Busskamp
- Department of Ophthalmology, Universitäts-Augenklinik Bonn, University of Bonn, Ernst-Abbe-Straße 2, D-53127 Bonn, Germany
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Konduri AK, Deepak CS, Purohit S, Narayan KS. An integrated 3D fluidic device with bubble guidance mechanism for long-term primary and secondary cell recordings on multi-electrode array platform. Biofabrication 2020; 12:045019. [PMID: 32650326 DOI: 10.1088/1758-5090/aba500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A 3D fluidic device (3D-FD) is designed and developed with the capability of auto bubble guidance via a helical pathway in a 3D geometry. This assembly is integrated to a multi-electrode array (MEA) to maintain secondary cell lines, primary cells and primary retinal tissue explants of chick embryos for continuous monitoring of the growth and electrophysiology recording. The ability to maintain the retinal tissue explant, extracted from day 14 (E-14) and day 21 (E-21) chick embryos in an integrated 3D-FD MEA for long duration (>100 h) and study the development is demonstrated. The enhanced duration of monitoring offered by this device is due to the controlled laminar flow and the maintenance of a stable microenvironment. The spontaneous electrical activity of the retina, including the spike recordings from the retinal ganglion layer, was monitored over a long duration. Specifically, the spiking activity in embryonic chick retinas of different days (E-14 to 21) is studied, and the presence of light-stimulated firings along with a distinct electroretinogram for E-21 mature retina provides the evidence of a stable microenvironment over a sustained period.
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Affiliation(s)
- Anil Krishna Konduri
- Chemistry and Physics of Material Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur-560064, Bangalore, Karnataka, India
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Pfister BJ, Grasman JM, Loverde JR. Exploiting biomechanics to direct the formation of nervous tissue. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2020. [DOI: 10.1016/j.cobme.2020.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hondrich TJJ, Lenyk B, Shokoohimehr P, Kireev D, Maybeck V, Mayer D, Offenhäusser A. MEA Recordings and Cell-Substrate Investigations with Plasmonic and Transparent, Tunable Holey Gold. ACS APPLIED MATERIALS & INTERFACES 2019; 11:46451-46461. [PMID: 31752486 DOI: 10.1021/acsami.9b14948] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Microelectrode arrays are widely used in different fields such as neurobiology or biomedicine to read out electrical signals from cells or biomolecules. One way to improve microelectrode applications is the development of novel electrode materials with enhanced or additional functionality. In this study, we fabricated macroelectrodes and microelectrode arrays containing gold penetrated by nanohole arrays as a conductive layer. We used this holey gold to optically excite surface plasmon polaritons, which lead to a strong increase in transparency, an effect that is further enhanced by the plasmon's interaction with cell culture medium. By varying the nanohole diameter in finite-difference time domain simulations, we demonstrate that the transmission can be increased to above 70% with its peak at a wavelength depending on the holey gold's lattice constant. Further, we demonstrate that the novel transparent microelectrode arrays are as suitable for recording cellular electrical activity as standard devices. Moreover, we prove using spectral measurements and finite-difference time domain simulations that plasmonically induced transmission peaks of holey gold red-shift upon sensing medium or cells in close vicinity (<30 nm) to the substrate. Thus, we establish plasmonic and transparent holey gold as a tunable material suitable for cellular electrical recordings and biosensing applications.
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Affiliation(s)
- Timm J J Hondrich
- Institute of Complex Systems, Bioelectronics (ICS-8) , Forschungszentrum Jülich , 52428 Jülich , Germany
- RWTH Aachen University , Aachen 52062 , Germany
| | - Bohdan Lenyk
- Institute of Complex Systems, Bioelectronics (ICS-8) , Forschungszentrum Jülich , 52428 Jülich , Germany
- Department of Physics , University of Konstanz , 78464 Konstanz , Germany
| | - Pegah Shokoohimehr
- Institute of Complex Systems, Bioelectronics (ICS-8) , Forschungszentrum Jülich , 52428 Jülich , Germany
- RWTH Aachen University , Aachen 52062 , Germany
| | - Dmitry Kireev
- Institute of Complex Systems, Bioelectronics (ICS-8) , Forschungszentrum Jülich , 52428 Jülich , Germany
- Department of Electrical and Computer Engineering , University of Texas at Austin , Austin , Texas 78712 , United States
| | - Vanessa Maybeck
- Institute of Complex Systems, Bioelectronics (ICS-8) , Forschungszentrum Jülich , 52428 Jülich , Germany
| | - Dirk Mayer
- Institute of Complex Systems, Bioelectronics (ICS-8) , Forschungszentrum Jülich , 52428 Jülich , Germany
| | - Andreas Offenhäusser
- Institute of Complex Systems, Bioelectronics (ICS-8) , Forschungszentrum Jülich , 52428 Jülich , Germany
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Cullen DK, Gordián-Vélez WJ, Struzyna LA, Jgamadze D, Lim J, Wofford KL, Browne KD, Chen HI. Bundled Three-Dimensional Human Axon Tracts Derived from Brain Organoids. iScience 2019; 21:57-67. [PMID: 31654854 PMCID: PMC6820245 DOI: 10.1016/j.isci.2019.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 06/27/2019] [Accepted: 09/30/2019] [Indexed: 12/20/2022] Open
Abstract
Reestablishing cerebral connectivity is a critical part of restoring neuronal network integrity and brain function after trauma, stroke, and neurodegenerative diseases. Creating transplantable axon tracts in the laboratory is an unexplored strategy for overcoming the common barriers limiting axon regeneration in vivo, including growth-inhibiting factors and the limited outgrowth capacity of mature neurons in the brain. We describe the generation, phenotype, and connectivity of constrained three-dimensional human axon tracts derived from brain organoids. These centimeter-long constructs are encased in an agarose shell that permits physical manipulation and are composed of discrete cellular regions spanned by axon tracts, mirroring the separation of cerebral gray and white matter. Features of cerebral cortex also are emulated, as evidenced by the presence of neurons with different cortical layer phenotypes. This engineered neural tissue represents a first step toward potentially reconstructing brain circuits by physically replacing neuronal populations and long-range axon tracts in the brain. Transplantable 3D axon tracts are tissue engineered from human brain organoids Growth of organoid axons in a hydrogel column is enhanced compared with planar culture Organoids within engineered columns can maintain a laminar cortical architecture Functional connectivity across the construct is demonstrated using calcium imaging
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Affiliation(s)
- D Kacy Cullen
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, 3rd Floor, Silverstein Pavilion/3400 Spruce Street, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA; Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Wisberty J Gordián-Vélez
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, 3rd Floor, Silverstein Pavilion/3400 Spruce Street, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA; Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Laura A Struzyna
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, 3rd Floor, Silverstein Pavilion/3400 Spruce Street, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA; Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dennis Jgamadze
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, 3rd Floor, Silverstein Pavilion/3400 Spruce Street, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - James Lim
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, 3rd Floor, Silverstein Pavilion/3400 Spruce Street, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Kathryn L Wofford
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, 3rd Floor, Silverstein Pavilion/3400 Spruce Street, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - Kevin D Browne
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, 3rd Floor, Silverstein Pavilion/3400 Spruce Street, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA
| | - H Isaac Chen
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, 3rd Floor, Silverstein Pavilion/3400 Spruce Street, Philadelphia, PA 19104, USA; Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA 19104, USA.
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Hondrich TJJ, Deußen O, Grannemann C, Brinkmann D, Offenhäusser A. Improvements of Microcontact Printing for Micropatterned Cell Growth by Contrast Enhancement. MICROMACHINES 2019; 10:E659. [PMID: 31574944 PMCID: PMC6848919 DOI: 10.3390/mi10100659] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 12/26/2022]
Abstract
Patterned neuronal cell cultures are important tools for investigating neuronal signal integration, network function, and cell-substrate interactions. Because of the variable nature of neuronal cells, the widely used coating method of microcontact printing is in constant need of improvements and adaptations depending on the pattern, cell type, and coating solutions available for a certain experimental system. In this work, we report on three approaches to modify microcontact printing on borosilicate glass surfaces, which we evaluate with contact angle measurements and by determining the quality of patterned neuronal growth. Although background toxification with manganese salt does not result in the desired pattern enhancement, a simple heat treatment of the glass substrates leads to improved background hydrophobicity and therefore neuronal patterning. Thirdly, we extended a microcontact printing process based on covalently linking the glass surface and the coating molecule via an epoxysilane. This extension is an additional hydrophobization step with dodecylamine. We demonstrate that shelf life of the silanized glass is at least 22 weeks, leading to consistently reliable neuronal patterning by microcontact printing. Thus, we compared three practical additions to microcontact printing, two of which can easily be implemented into a workflow for the investigation of patterned neuronal networks.
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Affiliation(s)
- Timm J J Hondrich
- Institute of Complex Systems, Bioelectronics (ICS-8), Forschungszentrum Jülich, 52428 Jülich, Germany.
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52076 Aachen, Germany.
| | - Oliver Deußen
- Institute of Complex Systems, Bioelectronics (ICS-8), Forschungszentrum Jülich, 52428 Jülich, Germany.
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52076 Aachen, Germany.
| | - Caroline Grannemann
- Institute of Complex Systems, Bioelectronics (ICS-8), Forschungszentrum Jülich, 52428 Jülich, Germany.
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52076 Aachen, Germany.
| | - Dominik Brinkmann
- Institute of Complex Systems, Bioelectronics (ICS-8), Forschungszentrum Jülich, 52428 Jülich, Germany.
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52076 Aachen, Germany.
| | - Andreas Offenhäusser
- Institute of Complex Systems, Bioelectronics (ICS-8), Forschungszentrum Jülich, 52428 Jülich, Germany.
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Chen HI, Jgamadze D, Lim J, Mensah-Brown K, Wolf JA, Mills JA, Smith DH. Functional Cortical Axon Tracts Generated from Human Stem Cell-Derived Neurons. Tissue Eng Part A 2019; 25:736-745. [PMID: 30648482 DOI: 10.1089/ten.tea.2018.0270] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
IMPACT STATEMENT Axon regeneration is negligible in the adult mammalian brain, and thus, white matter damage often leads to permanent neurological deficits. A novel approach for axon repair is the generation of axon tracts in the laboratory setting followed by transplantation of these constructs. This article details a human substrate for this repair strategy. Using the technique of axon stretch growth, functional cortical axon tracts are generated from human pluripotent stem cells at rates of up to 1 mm/day. These results form the basis of a potential patient-specific protocol for cerebral axon transplantation after injury.
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Affiliation(s)
- H Isaac Chen
- 1 Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,2 Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Dennis Jgamadze
- 1 Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - James Lim
- 1 Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kobina Mensah-Brown
- 1 Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - John A Wolf
- 1 Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,2 Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania
| | - Jason A Mills
- 3 Center for Advanced Retinal and Ocular Therapeutics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Douglas H Smith
- 1 Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Chen HI, Song H, Ming GL. Applications of Human Brain Organoids to Clinical Problems. Dev Dyn 2019; 248:53-64. [PMID: 30091290 PMCID: PMC6312736 DOI: 10.1002/dvdy.24662] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/30/2018] [Accepted: 08/01/2018] [Indexed: 12/13/2022] Open
Abstract
Brain organoids are an exciting new technology with the potential to significantly change how diseases of the brain are understood and treated. These three-dimensional neural tissues are derived from the self-organization of pluripotent stem cells, and they recapitulate the developmental process of the human brain, including progenitor zones and rudimentary cortical layers. Brain organoids have been valuable in investigating different aspects of developmental neurobiology and comparative biology. Several characteristics of organoids also make them attractive as models of brain disorders. Data generated from human organoids are more generalizable to patients because of the match in species background. Personalized organoids also can be generated from patient-derived induced pluripotent stem cells. Furthermore, the three-dimensionality of brain organoids supports cellular, mechanical, and topographical cues that are lacking in planar systems. In this review, we discuss the translational potential of brain organoids, using the examples of Zika virus, autism-spectrum disorder, and glioblastoma multiforme to consider how they could contribute to disease modeling, personalized medicine, and testing of therapeutics. We then discuss areas of improvement in organoid technology that will enhance the translational potential of brain organoids, as well as the possibility of their use as substrates for repairing cerebral circuitry after injury. Developmental Dynamics 248:53-64, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- H. Isaac Chen
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Hongjun Song
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- The Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Guo-li Ming
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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Dhobale AV, Adewole DO, Chan AHW, Marinov T, Serruya MD, Kraft RH, Cullen DK. Assessing functional connectivity across 3D tissue engineered axonal tracts using calcium fluorescence imaging. J Neural Eng 2018; 15:056008. [PMID: 29855432 PMCID: PMC6999858 DOI: 10.1088/1741-2552/aac96d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Micro-tissue engineered neural networks (micro-TENNs) are anatomically-inspired constructs designed to structurally and functionally emulate white matter pathways in the brain. These 3D neural networks feature long axonal tracts spanning discrete neuronal populations contained within a tubular hydrogel, and are being developed to reconstruct damaged axonal pathways in the brain as well as to serve as physiologically-relevant in vitro experimental platforms. The goal of the current study was to characterize the functional properties of these neuronal and axonal networks. APPROACH Bidirectional micro-TENNs were transduced to express genetically-encoded calcium indicators, and spontaneous fluorescence activity was recorded using real-time microscopy at 20 Hz from specific regions-of-interest in the neuronal populations. Network activity patterns and functional connectivity across the axonal tracts were then assessed using various techniques from statistics and information theory including Pearson cross-correlation, phase synchronization matrices, power spectral analysis, directed transfer function, and transfer entropy. MAIN RESULTS Pearson cross-correlation, phase synchronization matrices, and power spectral analysis revealed high values of correlation and synchronicity between the spatially segregated neuronal clusters connected by axonal tracts. Specifically, phase synchronization revealed high synchronicity of >0.8 between micro-TENN regions of interest. Normalized directed transfer function and transfer entropy matrices suggested robust information flow between the neuronal populations. Time varying power spectrum analysis revealed the strength of information propagation at various frequencies. Signal power strength was visible at elevated peak levels for dominant delta (1-4 Hz) and theta (4-8 Hz) frequency bands and progressively weakened at higher frequencies. These signal power strength results closely matched normalized directed transfer function analysis where near synchronous information flow was detected between frequencies of 2-5 Hz. SIGNIFICANCE To our knowledge, this is the first report using directed transfer function and transfer entropy methods based on fluorescent calcium activity to estimate functional connectivity of distinct neuronal populations via long-projecting, 3D axonal tracts in vitro. These functional data will further improve the design and optimization of implantable neural networks that could ultimately be deployed to reconstruct the nervous system to treat neurological disease and injury.
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Affiliation(s)
- Anjali Vijay Dhobale
- The Penn State Computational Biomechanics Group, The Pennsylvania State University, University Park, PA, USA
| | - Dayo O. Adewole
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Andy Ho Wing Chan
- Department of Neurology and Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA
| | - Toma Marinov
- The Penn State Computational Biomechanics Group, The Pennsylvania State University, University Park, PA, USA
| | - Mijail D. Serruya
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
- Department of Neurology and Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, USA
| | - Reuben H. Kraft
- The Penn State Computational Biomechanics Group, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - D. Kacy Cullen
- Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
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