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Lewis CM, Hoffmann A, Helmchen F. Linking brain activity across scales with simultaneous opto- and electrophysiology. NEUROPHOTONICS 2024; 11:033403. [PMID: 37662552 PMCID: PMC10472193 DOI: 10.1117/1.nph.11.3.033403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/19/2023] [Accepted: 07/24/2023] [Indexed: 09/05/2023]
Abstract
The brain enables adaptive behavior via the dynamic coordination of diverse neuronal signals across spatial and temporal scales: from fast action potential patterns in microcircuits to slower patterns of distributed activity in brain-wide networks. Understanding principles of multiscale dynamics requires simultaneous monitoring of signals in multiple, distributed network nodes. Combining optical and electrical recordings of brain activity is promising for collecting data across multiple scales and can reveal aspects of coordinated dynamics invisible to standard, single-modality approaches. We review recent progress in combining opto- and electrophysiology, focusing on mouse studies that shed new light on the function of single neurons by embedding their activity in the context of brain-wide activity patterns. Optical and electrical readouts can be tailored to desired scales to tackle specific questions. For example, fast dynamics in single cells or local populations recorded with multi-electrode arrays can be related to simultaneously acquired optical signals that report activity in specified subpopulations of neurons, in non-neuronal cells, or in neuromodulatory pathways. Conversely, two-photon imaging can be used to densely monitor activity in local circuits while sampling electrical activity in distant brain areas at the same time. The refinement of combined approaches will continue to reveal previously inaccessible and under-appreciated aspects of coordinated brain activity.
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Affiliation(s)
| | - Adrian Hoffmann
- University of Zurich, Brain Research Institute, Zurich, Switzerland
- University of Zurich, Neuroscience Center Zurich, Zurich, Switzerland
| | - Fritjof Helmchen
- University of Zurich, Brain Research Institute, Zurich, Switzerland
- University of Zurich, Neuroscience Center Zurich, Zurich, Switzerland
- University of Zurich, University Research Priority Program, Adaptive Brain Circuits in Development and Learning, Zurich, Switzerland
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2
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Câmara BO, Guimarães JG, Pereira Junior ML. Analog neuromorphic circuit for spontaneous Ca 2+ oscillations. Sci Rep 2023; 13:20107. [PMID: 37973824 PMCID: PMC10654768 DOI: 10.1038/s41598-023-47433-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 11/14/2023] [Indexed: 11/19/2023] Open
Abstract
This study proposes an innovative analog neuromorphic circuit design to mimic spontaneous Ca2+ oscillations observed in astrocytes. Unlike traditional models, this approach does not rely on synaptic stimulation, suggesting that astrocytes may play a key role in generating neuronal activity. The circuit is built using transistor differential pairs to approximate the nonlinear sigmoidal biological functions, and its performance is validated through simulation and compared against mathematical models using phase diagram analysis. Results indicate a good fit between the circuit and the mathematical model. Finally, the circuit's ability to simulate the release of glutamate and ATP through spontaneous oscillations is demonstrated.
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Affiliation(s)
- Beatriz O Câmara
- Department of Electrical Engineering, Faculty of Technology, University of Brasília, 70910-900, Brasília, Brazil
| | - Janaina G Guimarães
- Federal University of Santa Catarina, Control Engineering, Automation and Computer Science, 89036-256, Blumenau, Santa Catarina, Brazil
| | - Marcelo L Pereira Junior
- Department of Electrical Engineering, Faculty of Technology, University of Brasília, 70910-900, Brasília, Brazil.
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3
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Zhu Y, Yang Y, Ni G, Li S, Liu W, Gao Z, Zhang X, Zhang Q, Wang C, Zhou J. On-demand electrically controlled melatonin release from PEDOT/SNP composite improves quality of chronic neural recording. Front Bioeng Biotechnol 2023; 11:1284927. [PMID: 38033812 PMCID: PMC10684936 DOI: 10.3389/fbioe.2023.1284927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/06/2023] [Indexed: 12/02/2023] Open
Abstract
Long-time and high-quality signal acquisition performance from implantable electrodes is the key to establish stable and efficient brain-computer interface (BCI) connections. The chronic performance of implantable electrodes is hindered by the inflammatory response of brain tissue. In order to solve the material limitation of biological interface electrodes, we designed sulfonated silica nanoparticles (SNPs) as the dopant of Poly (3,4-ethylenedioxythiophene) (PEDOT) to modify the implantable electrodes. In this work, melatonin (MT) loaded SNPs were incorporated in PEDOT via electrochemical deposition on nickel-chromium (Ni-Cr) alloy electrode and carbon nanotube (CNT) fiber electrodes, without affecting the acute neural signal recording capacity. After coating with PEDOT/SNP-MT, the charge storage capacity of both electrodes was significantly increased, and the electrochemical impedance at 1 kHz of the Ni-Cr alloy electrodes was significantly reduced, while that of the CNT electrodes was significantly increased. In addition, this study inspected the effect of electrically triggered MT release every other day on the quality and longevity of neural recording from implanted neural electrodes in rat hippocampus for 1 month. Both MT modified Ni-Cr alloy electrodes and CNT electrodes showed significantly higher spike amplitude after 26-day recording. Significantly, the histological studies showed that the number of astrocytes around the implanted Ni-Cr alloy electrodes was significantly reduced after MT release. These results demonstrate the potent outcome of PEDOT/SNP-MT treatment in improving the chronic neural recording quality possibly through its anti-inflammatory property.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Changyong Wang
- Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Jin Zhou
- Beijing Institute of Basic Medical Sciences, Beijing, China
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4
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Cui H, Zhao S, Hong G. Wireless deep-brain neuromodulation using photovoltaics in the second near-infrared spectrum. DEVICE 2023; 1:100113. [PMID: 37990694 PMCID: PMC10659575 DOI: 10.1016/j.device.2023.100113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Conventional electrical neuromodulation techniques are constrained by the need for invasive implants in neural tissues, whereas methods using optogenetic are subjected to genetic alterations and hampered by the poor tissue penetration of visible light. Photovoltaic neuromodulation using light from the second near-infrared (NIR-II) spectrum, which minimizes scattering and enhances tissue penetration, shows promise as an alternative to existing neuromodulation technologies. NIR-II light has been used in deep-tissue imaging and in deep-brain photothermal neuromodulation via nanotransducers. This Perspective will provide an overview for the underpinning mechanisms of photovoltaic neuromodulation and identify avenues for future research in materials science and bioengineering that can further advance NIR-II photovoltaic neuromodulation methods.
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Affiliation(s)
- Han Cui
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305, USA
| | - Su Zhao
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305, USA
| | - Guosong Hong
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, 94305, USA
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5
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Zhang Y, Wu X, Ding J, Su B, Chen Z, Xiao Z, Wu C, Wei D, Sun J, Luo F, Yin H, Fan H. Wireless-Powering Deep Brain Stimulation Platform Based on 1D-Structured Magnetoelectric Nanochains Applied in Antiepilepsy Treatment. ACS NANO 2023; 17:15796-15809. [PMID: 37530448 DOI: 10.1021/acsnano.3c03661] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
Electrical deep brain stimulation (DBS) is a top priority for pharmacoresistant epilepsy treatment, while less-invasive wireless DBS is an urgent priority but challenging. Herein, we developed a conceptual wireless DBS platform to realize local electric stimulation via 1D-structured magnetoelectric Fe3O4@BaTiO3 nanochains (FBC). The FBC was facilely synthesized via magnetic-assisted interface coassembly, possessing a higher electrical output by inducing larger local strain from the anisotropic structure and strain coherence. Subsequently, wireless magnetoelectric neuromodulation in vitro was synergistically achieved by voltage-gated ion channels and to a lesser extent, the mechanosensitive ion channels. Furthermore, FBC less-invasively injected into the anterior nucleus of the thalamus (ANT) obviously inhibited acute and continuous seizures under magnetic loading, exhibiting excellent therapeutic effects in suppressing both high voltage electroencephalogram signals propagation and behavioral seizure stage and neuroprotection of the hippocampus mediated via the Papez circuit similar to conventional wired-in DBS. This work establishes an advanced antiepilepsy strategy and provides a perspective for other neurological disorder treatment.
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Affiliation(s)
- Yusheng Zhang
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
| | - Xiaoyang Wu
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
| | - Jie Ding
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
| | - Borui Su
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
| | - Zhihong Chen
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
| | - Zhanwen Xiao
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
| | - Chengheng Wu
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
- Institute of Regulatory Science for Medical Devices, Sichuan University, Chengdu 610064, Sichuan, China
| | - Dan Wei
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
| | - Jing Sun
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
| | - Fang Luo
- The Center of Gerontology and Geriatrics, West China Hospital, Sichuan University, Chengdu 610064, Sichuan, China
| | - Huabing Yin
- James Watt School of Engineering, University of Glasgow, Glasgow G12 8LT, U.K
| | - Hongsong Fan
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu 610064, Sichuan, China
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6
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Wu X, Yang F, Cai S, Pu K, Hong G. Nanotransducer-Enabled Deep-Brain Neuromodulation with NIR-II Light. ACS NANO 2023; 17:7941-7952. [PMID: 37079455 DOI: 10.1021/acsnano.2c12068] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The second near-infrared window (NIR-II window), which ranges from 1000 to 1700 nm in wavelength, exhibits distinctive advantages of reduced light scattering and thus deep penetration in biological tissues in comparison to the visible spectrum. The NIR-II window has been widely employed for deep-tissue fluorescence imaging in the past decade. More recently, deep-brain neuromodulation has been demonstrated in the NIR-II window by leveraging nanotransducers that can efficiently convert brain-penetrant NIR-II light into heat. In this Perspective, we discuss the principles and potential applications of this NIR-II deep-brain neuromodulation technique, together with its advantages and limitations compared with other existing optical methods for deep-brain neuromodulation. We also point out a few future directions where the advances in materials science and bioengineering can expand the capability and utility of NIR-II neuromodulation methods.
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Affiliation(s)
- Xiang Wu
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, California 94305, USA
| | - Fan Yang
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, California 94305, USA
| | - Sa Cai
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, California 94305, USA
| | - Kanyi Pu
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637457, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore
| | - Guosong Hong
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, California 94305, USA
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7
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Stuart T, Jeang WJ, Slivicki RA, Brown BJ, Burton A, Brings VE, Alarcón-Segovia LC, Agyare P, Ruiz S, Tyree A, Pruitt L, Madhvapathy S, Niemiec M, Zhuang J, Krishnan S, Copits BA, Rogers JA, Gereau RW, Samineni VK, Bandodkar AJ, Gutruf P. Wireless, Battery-Free Implants for Electrochemical Catecholamine Sensing and Optogenetic Stimulation. ACS NANO 2023; 17:561-574. [PMID: 36548126 DOI: 10.1021/acsnano.2c09475] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Neurotransmitters and neuromodulators mediate communication between neurons and other cell types; knowledge of release dynamics is critical to understanding their physiological role in normal and pathological brain function. Investigation into transient neurotransmitter dynamics has largely been hindered due to electrical and material requirements for electrochemical stimulation and recording. Current systems require complex electronics for biasing and amplification and rely on materials that offer limited sensor selectivity and sensitivity. These restrictions result in bulky, tethered, or battery-powered systems impacting behavior and that require constant care of subjects. To overcome these challenges, we demonstrate a fully implantable, wireless, and battery-free platform that enables optogenetic stimulation and electrochemical recording of catecholamine dynamics in real time. The device is nearly 1/10th the size of previously reported examples and includes a probe that relies on a multilayer electrode architecture featuring a microscale light emitting diode (μ-LED) and a carbon nanotube (CNT)-based sensor with sensitivities among the highest recorded in the literature (1264.1 nA μM-1 cm-2). High sensitivity of the probe combined with a center tapped antenna design enables the realization of miniaturized, low power circuits suitable for subdermal implantation even in small animal models such as mice. A series of in vitro and in vivo experiments highlight the sensitivity and selectivity of the platform and demonstrate its capabilities in freely moving, untethered subjects. Specifically, a demonstration of changes in dopamine concentration after optogenetic stimulation of the nucleus accumbens and real-time readout of dopamine levels after opioid and naloxone exposure in freely behaving subjects highlight the experimental paradigms enabled by the platform.
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Affiliation(s)
- Tucker Stuart
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - William J Jeang
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60201, United States
| | - Richard A Slivicki
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Washington University Pain Center, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Bobbie J Brown
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Washington University Pain Center, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Alex Burton
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Victoria E Brings
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Washington University Pain Center, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Lilian C Alarcón-Segovia
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois 60201, United States
| | - Prophecy Agyare
- Department of Neuroscience, Northwestern University, Evanston, Illinois 60201, United States
| | - Savanna Ruiz
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60201, United States
| | - Amanda Tyree
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Lindsay Pruitt
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Surabhi Madhvapathy
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60201, United States
| | - Martin Niemiec
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - James Zhuang
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
| | - Siddharth Krishnan
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois 60201, United States
| | - Bryan A Copits
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Washington University Pain Center, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - John A Rogers
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60201, United States
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, Illinois 60201, United States
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60201, United States
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60201, United States
- Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Evanston, Illinois 60201, United States
- Department of Neurological Surgery, Northwestern University, Evanston, Illinois 60208, United States
- Center for Bio-Integrated Electronics, Northwestern University, Evanston, Illinois 60208, United States
| | - Robert W Gereau
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Washington University Pain Center, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Department of Neuroscience, Washington University, St. Louis, Missouri 63110, United States
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63110, United States
| | - Vijay K Samineni
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Washington University Pain Center, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Amay J Bandodkar
- Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
- Center for Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST), North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Philipp Gutruf
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85721, United States
- Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona 85721, United States
- Bio5 Institute, University of Arizona, Tucson, Arizona 85721, United States
- Neuroscience GIDP, University of Arizona, Tucson, Arizona 85721, United States
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8
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Entenberg D, Oktay MH, Condeelis JS. Intravital imaging to study cancer progression and metastasis. Nat Rev Cancer 2023; 23:25-42. [PMID: 36385560 PMCID: PMC9912378 DOI: 10.1038/s41568-022-00527-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/11/2022] [Indexed: 11/17/2022]
Abstract
Navigation through the bulk tumour, entry into the blood vasculature, survival in the circulation, exit at distant sites and resumption of proliferation are all steps necessary for tumour cells to successfully metastasize. The ability of tumour cells to complete these steps is highly dependent on the timing and sequence of the interactions that these cells have with the tumour microenvironment (TME), including stromal cells, the extracellular matrix and soluble factors. The TME thus plays a major role in determining the overall metastatic phenotype of tumours. The complexity and cause-and-effect dynamics of the TME cannot currently be recapitulated in vitro or inferred from studies of fixed tissue, and are best studied in vivo, in real time and at single-cell resolution. Intravital imaging (IVI) offers these capabilities, and recent years have been a time of immense growth and innovation in the field. Here we review some of the recent advances in IVI of mammalian models of cancer and describe how IVI is being used to understand cancer progression and metastasis, and to develop novel treatments and therapies. We describe new techniques that allow access to a range of tissue and cancer types, novel fluorescent reporters and biosensors that allow fate mapping and the probing of functional and phenotypic states, and the clinical applications that have arisen from applying these techniques, reporters and biosensors to study cancer. We finish by presenting some of the challenges that remain in the field, how to address them and future perspectives.
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Affiliation(s)
- David Entenberg
- Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
- Integrated Imaging Program, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
- Department of Pathology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
| | - Maja H Oktay
- Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
- Integrated Imaging Program, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
- Department of Pathology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
- Department of Surgery, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
| | - John S Condeelis
- Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
- Integrated Imaging Program, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
- Department of Surgery, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
- Department of Cell Biology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.
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9
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Zhao C, Man T, Cao Y, Weiss PS, Monbouquette HG, Andrews AM. Flexible and Implantable Polyimide Aptamer-Field-Effect Transistor Biosensors. ACS Sens 2022; 7:3644-3653. [PMID: 36399772 PMCID: PMC9982941 DOI: 10.1021/acssensors.2c01909] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Monitoring neurochemical signaling across time scales is critical to understanding how brains encode and store information. Flexible (vs stiff) devices have been shown to improve in vivo monitoring, particularly over longer times, by reducing tissue damage and immunological responses. Here, we report our initial steps toward developing flexible and implantable neuroprobes with aptamer-field-effect transistor (FET) biosensors for neurotransmitter monitoring. A high-throughput process was developed to fabricate thin, flexible polyimide probes using microelectromechanical-system (MEMS) technologies, where 150 flexible probes were fabricated on each 4 in. Si wafer. Probes were 150 μm wide and 7 μm thick with two FETs per tip. The bending stiffness was 1.2 × 10-11 N·m2. Semiconductor thin films (3 nm In2O3) were functionalized with DNA aptamers for target recognition, which produces aptamer conformational rearrangements detected via changes in FET conductance. Flexible aptamer-FET neuroprobes detected serotonin at femtomolar concentrations in high-ionic strength artificial cerebrospinal fluid. A straightforward implantation process was developed, where microfabricated Si carrier devices assisted with implantation such that flexible neuroprobes detected physiological relevant serotonin in a tissue-hydrogel brain mimic.
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Affiliation(s)
- Chuanzhen Zhao
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Tianxing Man
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Yan Cao
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States,Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Paul S. Weiss
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States,Departments of Bioengineering and Materials Science and Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Harold G. Monbouquette
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States,Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Anne M. Andrews
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California 90095, United States,Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience & Human Behavior, and Hatos Center for Neuropharmacology, University of California, Los Angeles, Los Angeles, California 90095, United States,To whom correspondence should be addressed to:
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10
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He F, Sun Y, Jin Y, Yin R, Zhu H, Rathore H, Xie C, Luan L. Longitudinal neural and vascular recovery following ultraflexible neural electrode implantation in aged mice. Biomaterials 2022; 291:121905. [PMID: 36403326 PMCID: PMC9701172 DOI: 10.1016/j.biomaterials.2022.121905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/24/2022] [Accepted: 11/04/2022] [Indexed: 11/16/2022]
Abstract
Flexible neural electrodes improve the recording longevity and quality of individual neurons by promoting tissue-electrode integration. However, the intracortical implantation of flexible electrodes inevitably induces tissue damage. Understanding the longitudinal neural and vascular recovery following the intracortical implantation is critical for the ever-growing applications of flexible electrodes in both healthy and disordered brains. Aged animals are of particular interest because they play a key role in modeling neurological disorders, but their tissue-electrode interface remains mostly unstudied. Here we integrate in-vivo two-photon imaging and electrophysiological recording to determine the time-dependent neural and vascular dynamics after the implantation of ultraflexible neural electrodes in aged mice. We find heightened angiogenesis and vascular remodeling in the first two weeks after implantation, which coincides with the rapid increase in local field potentials and unit activities detected by electrophysiological recordings. Vascular remodeling in shallow cortical layers preceded that in deeper layers, which often lasted longer than the recovery of neural signals. By six weeks post-implantation vascular abnormalities had subsided, resulting in normal vasculature and microcirculation. Putative cell classification based on firing pattern and waveform shows similar recovery time courses in fast-spiking interneurons and pyramidal neurons. These results elucidate how structural damages and remodeling near implants affecting recording efficacy, and support the application of ultraflexible electrodes in aged animals at minimal perturbations to endogenous neurophysiology.
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Affiliation(s)
- Fei He
- Department of Electrical and Computer Engineering, Rice University, Houston, USA; Rice Neuroengineering Initiative, Rice University, Houston, USA
| | - Yingchu Sun
- Department of Electrical and Computer Engineering, Rice University, Houston, USA; Rice Neuroengineering Initiative, Rice University, Houston, USA
| | - Yifu Jin
- Department of Electrical and Computer Engineering, Rice University, Houston, USA; Rice Neuroengineering Initiative, Rice University, Houston, USA
| | - Rongkang Yin
- Department of Electrical and Computer Engineering, Rice University, Houston, USA; Rice Neuroengineering Initiative, Rice University, Houston, USA
| | - Hanlin Zhu
- Department of Electrical and Computer Engineering, Rice University, Houston, USA; Rice Neuroengineering Initiative, Rice University, Houston, USA
| | - Haad Rathore
- Rice Neuroengineering Initiative, Rice University, Houston, USA; Applied Physics Graduate Program, Rice University, Houston, USA
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, Houston, USA; Rice Neuroengineering Initiative, Rice University, Houston, USA; Department of Bioengineering, Rice University, Houston, USA
| | - Lan Luan
- Department of Electrical and Computer Engineering, Rice University, Houston, USA; Rice Neuroengineering Initiative, Rice University, Houston, USA; Department of Bioengineering, Rice University, Houston, USA.
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11
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Tringides CM, Mooney DJ. Materials for Implantable Surface Electrode Arrays: Current Status and Future Directions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107207. [PMID: 34716730 DOI: 10.1002/adma.202107207] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/26/2021] [Indexed: 06/13/2023]
Abstract
Surface electrode arrays are mainly fabricated from rigid or elastic materials, and precisely manipulated ductile metal films, which offer limited stretchability. However, the living tissues to which they are applied are nonlinear viscoelastic materials, which can undergo significant mechanical deformation in dynamic biological environments. Further, the same arrays and compositions are often repurposed for vastly different tissues rather than optimizing the materials and mechanical properties of the implant for the target application. By first characterizing the desired biological environment, and then designing a technology for a particular organ, surface electrode arrays may be more conformable, and offer better interfaces to tissues while causing less damage. Here, the various materials used in each component of a surface electrode array are first reviewed, and then electrically active implants in three specific biological systems, the nervous system, the muscular system, and skin, are described. Finally, the fabrication of next-generation surface arrays that overcome current limitations is discussed.
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Affiliation(s)
- Christina M Tringides
- Harvard Program in Biophysics, Harvard University, Cambridge, MA, 02138, USA
- Harvard-MIT Division in Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
| | - David J Mooney
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
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12
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Avila R, Wu Y, Garziera R, Rogers JA, Huang Y. Analytical Modeling of Flowrate and Its Maxima in Electrochemical Bioelectronics with Drug Delivery Capabilities. RESEARCH (WASHINGTON, D.C.) 2022; 2022:9805932. [PMID: 35316891 PMCID: PMC8917966 DOI: 10.34133/2022/9805932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 02/16/2022] [Indexed: 11/06/2022]
Abstract
Flowrate control in flexible bioelectronics with targeted drug delivery capabilities is essential to ensure timely and safe delivery. For neuroscience and pharmacogenetics studies in small animals, these flexible bioelectronic systems can be tailored to deliver small drug volumes on a controlled fashion without damaging surrounding tissues from stresses induced by excessively high flowrates. The drug delivery process is realized by an electrochemical reaction that pressurizes the internal bioelectronic chambers to deform a flexible polymer membrane that pumps the drug through a network of microchannels implanted in the small animal. The flowrate temporal profile and global maximum are governed and can be modeled by the ideal gas law. Here, we obtain an analytical solution that groups the relevant mechanical, fluidic, environmental, and electrochemical terms involved in the drug delivery process into a set of three nondimensional parameters. The unique combinations of these three nondimensional parameters (related to the initial pressure, initial gas volume, and microfluidic resistance) can be used to model the flowrate and scale up the flexible bioelectronic design for experiments in medium and large animal models. The analytical solution is divided into (1) a fast variable that controls the maximum flowrate and (2) a slow variable that models the temporal profile. Together, the two variables detail the complete drug delivery process and control using the three nondimensional parameters. Comparison of the analytical model with alternative numerical models shows excellent agreement and validates the analytic modeling approach. These findings serve as a theoretical framework to design and optimize future flexible bioelectronic systems used in biomedical research, or related medical fields, and analytically control the flowrate and its global maximum for successful drug delivery.
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Affiliation(s)
- Raudel Avila
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Yixin Wu
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA.,Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA
| | - Rinaldo Garziera
- Dipartimento di Ingegneria ed Architettura, Università di Parma, Italy
| | - John A Rogers
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA.,Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA.,Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA.,Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA.,Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL 60208, USA.,Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.,Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Yonggang Huang
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA.,Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA.,Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL 60208, USA.,Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208, USA
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13
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Kiang L, Woodington B, Carnicer-Lombarte A, Malliaras G, Barone DG. Spinal cord bioelectronic interfaces: opportunities in neural recording and clinical challenges. J Neural Eng 2022; 19. [PMID: 35320780 DOI: 10.1088/1741-2552/ac605f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 03/23/2022] [Indexed: 11/11/2022]
Abstract
Bioelectronic stimulation of the spinal cord has demonstrated significant progress in restoration of motor function in spinal cord injury (SCI). The proximal, uninjured spinal cord presents a viable target for the recording and generation of control signals to drive targeted stimulation. Signals have been directly recorded from the spinal cord in behaving animals and correlated with limb kinematics. Advances in flexible materials, electrode impedance and signal analysis will allow SCR to be used in next-generation neuroprosthetics. In this review, we summarize the technological advances enabling progress in SCR and describe systematically the clinical challenges facing spinal cord bioelectronic interfaces and potential solutions, from device manufacture, surgical implantation to chronic effects of foreign body reaction and stress-strain mismatches between electrodes and neural tissue. Finally, we establish our vision of bi-directional closed-loop spinal cord bioelectronic bypass interfaces that enable the communication of disrupted sensory signals and restoration of motor function in SCI.
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Affiliation(s)
- Lei Kiang
- Orthopaedic Surgery, Singapore General Hospital, Outram Road, Singapore, Singapore, 169608, SINGAPORE
| | - Ben Woodington
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Alejandro Carnicer-Lombarte
- Clinical Neurosciences, University of Cambridge, Bioelectronics Laboratory, Cambridge, CB2 0PY, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - George Malliaras
- University of Cambridge, University of Cambridge, Cambridge, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Damiano G Barone
- Department of Engineering, University of Cambridge, Electrical Engineering Division, 9 JJ Thomson Ave, Cambridge, Cambridge, Cambridgeshire, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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14
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Gao L, Wang J, Zhao Y, Li H, Liu M, Ding J, Tian H, Guan S, Fang Y. Free-Standing Nanofilm Electrode Arrays for Long-Term Stable Neural Interfacings. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107343. [PMID: 34796566 DOI: 10.1002/adma.202107343] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/16/2021] [Indexed: 06/13/2023]
Abstract
Flexible neural electrodes integrated on micrometer-thick polymer substrates offer important opportunities for improving the stability of neuronal activity recordings during cognitive processes. However, the bending stiffness of micrometer-thick polymer substrates is typically two orders of magnitude higher than that of nanofilm electrodes, making it a limiting factor in electrode-tissue interfacings. Here, this limitation is overcome by developing self-assembled nanofilm electrode arrays (NEAs) that consist of high-density, free-standing gold nanofilm electrodes. Chronically implanted NEAs can form intimate and innervated interfaces with neural tissue, enabling stable neuronal activity recordings across multiple brain regions over several months. As an application example, the activities of the same neuronal populations are tracked across odor discrimination reversal learning and it is illustrated how dorsal striatal neurons represent and update stimulus-outcome associations across multiple timescales. The results underscore the potential of free-standing nanoscale materials for interfacing biological systems over long terms.
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Affiliation(s)
- Lei Gao
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinfen Wang
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Yan Zhao
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082, China
| | - Hongbian Li
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Mengcheng Liu
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Jianfei Ding
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Huihui Tian
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Shouliang Guan
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Ying Fang
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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15
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Subdural neural interfaces for long-term electrical recording, optical microscopy and magnetic resonance imaging. Biomaterials 2021; 281:121352. [PMID: 34995902 DOI: 10.1016/j.biomaterials.2021.121352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 12/23/2021] [Accepted: 12/27/2021] [Indexed: 01/23/2023]
Abstract
Though commonly used, metal electrodes are incompatible with brain tissues, often leading to injury and failure to achieve long-term implantation. Here we report a subdural neural interface of hydrogel functioning as an ionic conductor, and elastomer as a dielectric. We demonstrate that it incurs a far less glial reaction and less cerebrovascular destruction than a metal electrode. Using a cat model, the hydrogel electrode was able to record electrical signals comparably in quality to a metal electrode. The hydrogel-elastomer neural interface also readily facilitated multimodal functions. Both the hydrogel and elastomer are transparent, enabling in vivo optical microscopy. For imaging, cerebral vessels and calcium signals were imaged using two-photon microscopy. The new electrode is compatible with magnetic resonance imaging and does not cause artifact images. Such a new multimodal neural interface could represent immediate opportunity for use in broad areas of application in neuroscience research and clinical neurology.
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16
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Cendra C, Balhorn L, Zhang W, O’Hara K, Bruening K, Tassone CJ, Steinrück HG, Liang M, Toney MF, McCulloch I, Chabinyc ML, Salleo A, Takacs CJ. Unraveling the Unconventional Order of a High-Mobility Indacenodithiophene-Benzothiadiazole Copolymer. ACS Macro Lett 2021; 10:1306-1314. [PMID: 35549036 DOI: 10.1021/acsmacrolett.1c00547] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new class of donor-acceptor (D-A) copolymers found to produce high charge carrier mobilities competitive with amorphous silicon (>1 cm2 V-1 s-1) exhibit the puzzling microstructure of substantial local order, however lacking long-range order and crystallinity previously deemed necessary for achieving high mobility. Here, we demonstrate the application of low-dose transmission electron microscopy to image and quantify the nanoscale and mesoscale organization of an archetypal D-A copolymer across areas comparable to electronic devices (≈9 μm2). The local structure is spatially resolved by mapping the backbone (001) spacing reflection, revealing nanocrystallites of aligned polymer chains throughout nearly the entire film. Analysis of the nanoscale structure of its ordered domains suggests significant short- and medium-range order and preferential grain boundary orientations. Moreover, we provide insights into the rich, interconnected mesoscale organization of this new family of D-A copolymers by analysis of the local orientational spatial autocorrelations.
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Affiliation(s)
- Camila Cendra
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Luke Balhorn
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Weimin Zhang
- Physical Science and Engineering Division KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Kathryn O’Hara
- Materials Department, University of California—Santa Barbara, Santa Barbara, California 93106, United States
| | - Karsten Bruening
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Christopher J. Tassone
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Hans-Georg Steinrück
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department Chemie, Universität Paderborn, 33098 Paderborn, Germany
| | - Mengning Liang
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Michael F. Toney
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- Department of Chemical and Biological Engineering, University of Colorado—Boulder, Boulder, Colorado 80303, United States
| | - Iain McCulloch
- Physical Science and Engineering Division KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Michael L. Chabinyc
- Materials Department, University of California—Santa Barbara, Santa Barbara, California 93106, United States
| | - Alberto Salleo
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Christopher J. Takacs
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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17
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Schweigmann M, Caudal LC, Stopper G, Scheller A, Koch KP, Kirchhoff F. Versatile Surface Electrodes for Combined Electrophysiology and Two-Photon Imaging of the Mouse Central Nervous System. Front Cell Neurosci 2021; 15:720675. [PMID: 34447299 PMCID: PMC8383317 DOI: 10.3389/fncel.2021.720675] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/19/2021] [Indexed: 11/23/2022] Open
Abstract
Understanding and modulating CNS function in physiological as well as pathophysiological contexts remains a significant ambition in research and clinical applications. The investigation of the multifaceted CNS cell types including their interactions and contributions to neural function requires a combination of the state-of-the-art in vivo electrophysiology and imaging techniques. We developed a novel type of liquid crystal polymer (LCP) surface micro-electrode manufactured in three customized designs with up to 16 channels for recording and stimulation of brain activity. All designs include spare central spaces for simultaneous 2P-imaging. Nanoporous platinum-plated contact sites ensure a low impedance and high current transfer. The epidural implantation of the LCP micro-electrodes could be combined with standard cranial window surgery. The epidurally positioned electrodes did not only display long-term biocompatibility, but we also observed an additional stabilization of the underlying CNS tissue. We demonstrate the electrode’s versatility in combination with in vivo 2P-imaging by monitoring anesthesia-awake cycles of transgenic mice with GCaMP3 expression in neurons or astrocytes. Cortical stimulation and simultaneous 2P Ca2+ imaging in neurons or astrocytes highlighted the astrocytes’ integrative character in neuronal activity processing. Furthermore, we confirmed that spontaneous astroglial Ca2+ signals are dampened under anesthesia, while evoked signals in neurons and astrocytes showed stronger dependency on stimulation intensity rather than on various levels of anesthesia. Finally, we show that the electrodes provide recordings of the electrocorticogram (ECoG) with a high signal-to noise ratio and spatial signal differences which help to decipher brain activity states during experimental procedures. Summarizing, the novel LCP surface micro-electrode is a versatile, convenient, and reliable tool to investigate brain function in vivo.
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Affiliation(s)
- Michael Schweigmann
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany.,Department of Electrical Engineering, Trier University of Applied Sciences, Trier, Germany
| | - Laura C Caudal
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Gebhard Stopper
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Anja Scheller
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Klaus P Koch
- Department of Electrical Engineering, Trier University of Applied Sciences, Trier, Germany
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
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18
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Cortelli G, Patruno L, Cramer T, Murgia M, Fraboni B, de Miranda S. Atomic Force Microscopy Nanomechanics of Hard Nanometer-Thick Films on Soft Substrates: Insights into Stretchable Conductors. ACS APPLIED NANO MATERIALS 2021; 4:8376-8382. [PMID: 34485845 PMCID: PMC8411650 DOI: 10.1021/acsanm.1c01590] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/06/2021] [Indexed: 05/14/2023]
Abstract
The nanomechanical properties of ultrathin and nanostructured films of rigid electronic materials on soft substrates are of crucial relevance to realize materials and devices for stretchable electronics. Of particular interest are bending deformations in buckled nanometer-thick films or patterned networks of rigid materials as they can be exploited to compensate for the missing tensile elasticity. Here, we perform atomic force microscopy indentation experiments and electrical measurements to characterize the nanomechanics of ultrathin gold films on a polydimethylsiloxane (PDMS) elastomer. The measured force-indentation data can be analyzed in terms of a simple analytical model describing a bending plate on a semi-infinite soft substrate. The resulting method enables us to quantify the local Young's modulus of elasticity of the nanometer-thick film. Systematic variation of the gold layer thickness reveals the presence of a diffuse interface between the metal film and the elastomer substrate that does not contribute to the bending stiffness. The effect is associated with gold clusters that penetrate the silicone and are not directly connected to the ultrathin film. Only above a critical layer thickness, percolation of the metallic thin film happens, causing a linear increase in bending stiffness and electrical conductivity.
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Affiliation(s)
- Giorgio Cortelli
- Department
of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Viale del Risorgimento 2, 40136 Bologna, Italy
| | - Luca Patruno
- Department
of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Viale del Risorgimento 2, 40136 Bologna, Italy
| | - Tobias Cramer
- Department
of Physics and Astronomy, University of
Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
| | - Mauro Murgia
- Department
of Physics and Astronomy, University of
Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
| | - Beatrice Fraboni
- Department
of Physics and Astronomy, University of
Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
| | - Stefano de Miranda
- Department
of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Viale del Risorgimento 2, 40136 Bologna, Italy
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19
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Rodríguez-Collado A, Rueda C. A simple parametric representation of the Hodgkin-Huxley model. PLoS One 2021; 16:e0254152. [PMID: 34292948 PMCID: PMC8297874 DOI: 10.1371/journal.pone.0254152] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 06/21/2021] [Indexed: 02/04/2023] Open
Abstract
The Hodgkin-Huxley model, decades after its first presentation, is still a reference model in neuroscience as it has successfully reproduced the electrophysiological activity of many organisms. The primary signal in the model represents the membrane potential of a neuron. A simple representation of this signal is presented in this paper. The new proposal is an adapted Frequency Modulated Möbius multicomponent model defined as a signal plus error model in which the signal is decomposed as a sum of waves. The main strengths of the method are the simple parametric formulation, the interpretability and flexibility of the parameters that describe and discriminate the waveforms, the estimators' identifiability and accuracy, and the robustness against noise. The approach is validated with a broad simulation experiment of Hodgkin-Huxley signals and real data from squid giant axons. Interesting differences between simulated and real data emerge from the comparison of the parameter configurations. Furthermore, the potential of the FMM parameters to predict Hodgkin-Huxley model parameters is shown using different Machine Learning methods. Finally, promising contributions of the approach in Spike Sorting and cell-type classification are detailed.
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Affiliation(s)
| | - Cristina Rueda
- Department of Statistics and Operations Research, Universidad de Valladolid, Valladolid, Spain
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