1
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Lorca-Cámara A, Blot FGC, Accanto N. Recent advances in light patterned optogenetic photostimulation in freely moving mice. NEUROPHOTONICS 2024; 11:S11508. [PMID: 38404422 PMCID: PMC10885521 DOI: 10.1117/1.nph.11.s1.s11508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/24/2024] [Accepted: 01/30/2024] [Indexed: 02/27/2024]
Abstract
Optogenetics opened the door to a new era of neuroscience. New optical developments are under way to enable high-resolution neuronal activity imaging and selective photostimulation of neuronal ensembles in freely moving animals. These advancements could allow researchers to interrogate, with cellular precision, functionally relevant neuronal circuits in the framework of naturalistic brain activity. We provide an overview of the current state-of-the-art of imaging and photostimulation in freely moving rodents and present a road map for future optical and engineering developments toward miniaturized microscopes that could reach beyond the currently existing systems.
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Affiliation(s)
| | - François G C Blot
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Nicolò Accanto
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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2
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Bao Y, Gong Y. Accurate neuron segmentation method for one-photon calcium imaging videos combining convolutional neural networks and clustering. Commun Biol 2024; 7:970. [PMID: 39122882 PMCID: PMC11316101 DOI: 10.1038/s42003-024-06668-7] [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: 11/07/2023] [Accepted: 08/01/2024] [Indexed: 08/12/2024] Open
Abstract
One-photon fluorescent calcium imaging helps understand brain functions by recording large-scale neural activities in freely moving animals. Automatic, fast, and accurate active neuron segmentation algorithms are essential to extract and interpret information from these videos. One-photon imaging videos' low resolution, high noise, and high background fluctuation pose significant challenges. Here, we develop a software pipeline to address the challenges of processing one-photon calcium imaging videos. We extend our previous two-photon active neuron segmentation algorithm, Shallow U-Net Neuron Segmentation (SUNS), to better suppress background fluctuations in one-photon videos. We also develop additional neuron extraction (ANE) to locate small or dim neurons missed by SUNS. To train our segmentation method, we create ground truth neurons by developing a manual labeling pipeline assisted with semi-automatic refinement. Our method is more accurate and faster than state-of-the-art techniques when processing simulated videos and multiple experimental datasets acquired over various brain regions with different imaging conditions.
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Affiliation(s)
- Yijun Bao
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311215, China.
| | - Yiyang Gong
- Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
- Department of Neurobiology, Duke University, Durham, NC, 27708, USA.
- Department of Cell Biology, University of Oklahoma Health Science Center, Oklahoma City, OK, 73104, USA.
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3
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Tabourin L, Bretzner F, Galstian T. Towards a mini-endoscope design with spatially selective excitation and imaging. BIOMEDICAL OPTICS EXPRESS 2024; 15:1750-1760. [PMID: 38495724 PMCID: PMC10942686 DOI: 10.1364/boe.512124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/06/2024] [Accepted: 02/06/2024] [Indexed: 03/19/2024]
Abstract
We describe a mini-endoscope design that uses a new type of electrically tunable liquid crystal lens array enabling the dynamic increase of spatial resolution by adjusting the working distance in various zones of interest over a relatively large field of view (FoV) without mechanical movement. The characterization of the system is performed by using uniform fluorescent films, fluorescent micro spheres and a tissue sample expressing the fluorescent calcium indicator GCaMP6s. Lateral resolution of up to 2 µm over the FoV between 300 µm - 400 µm is experimentally demonstrated.
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Affiliation(s)
- Loïc Tabourin
- Center for Optics, Photonics and Lasers (COPL), Faculty of Science and Engineering, Department of Physics, Engineering Physics and Optics, Université Laval, Québec, QC G1V 0A6, Canada
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - Frédéric Bretzner
- Centre de Recherche du CHU de Québec, CHUL-Neurosciences, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
- Faculty of Medicine, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC G1V 0A6, Canada
| | - Tigran Galstian
- Center for Optics, Photonics and Lasers (COPL), Faculty of Science and Engineering, Department of Physics, Engineering Physics and Optics, Université Laval, Québec, QC G1V 0A6, Canada
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4
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Zhao C, Zhu Y, Zhang D, Fu Q, Pan M, Wu R, Wang A, Cheng H. Millimeter field-of-view miniature two-photon microscopy for brain imaging in freely moving mice. OPTICS EXPRESS 2023; 31:32925-32934. [PMID: 37859084 DOI: 10.1364/oe.492674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 09/07/2023] [Indexed: 10/21/2023]
Abstract
Development of miniature two-photon microscopy (m2PM) has made it possible to observe fine structure and activity of neurons in the brain of freely moving animals. However, the imaging field-of-view of existing m2PM is still significantly smaller than that of miniature single-photon microscopy. Here we report that, through the design of low-magnification objective, large field-of-view scan lens and small tilt angle microscanner, a 2.5-g m2PM achieved a field-of-view of 1000 × 788 µm2, comparable to that of a typical single-photon miniscope. We demonstrated its capability by imaging neurons, dendrites and spines in the millimeter field-of-view, and simultaneous recording calcium activities, through a gradient-index lens, of approximately 400 neurons in the dorsal hippocampal CA1 in a freely moving mouse. Integrated with a detachable 1.2-g fast z-scanning module, it enables a 1000 × 788 × 500 µm3 volumetric neuronal imaging in the cerebral cortex. Thus, millimeter FOV m2PM provides a powerful tool for deciphering neuronal population dynamics in experimental paradigms allowing for animal's free movement.
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5
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Kim D, Gan Y, Nedergaard M, Kelley DH, Tithof J. Image Analysis Techniques for In Vivo Quantification of Cerebrospinal Fluid Flow. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.20.549937. [PMID: 37546970 PMCID: PMC10401935 DOI: 10.1101/2023.07.20.549937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Over the last decade, there has been a tremendously increased interest in understanding the neurophysiology of cerebrospinal fluid (CSF) flow, which plays a crucial role in clearing metabolic waste from the brain. This growing interest was largely initiated by two significant discoveries: the glymphatic system (a pathway for solute exchange between interstitial fluid deep within the brain and the CSF surrounding the brain) and meningeal lymphatic vessels (lymphatic vessels in the layer of tissue surrounding the brain that drain CSF). These two CSF systems work in unison, and their disruption has been implicated in several neurological disorders including Alzheimer's disease, stoke, and traumatic brain injury. Here, we present experimental techniques for in vivo quantification of CSF flow via direct imaging of fluorescent microspheres injected into the CSF. We discuss detailed image processing methods, including registration and masking of stagnant particles, to improve the quality of measurements. We provide guidance for quantifying CSF flow through particle tracking and offer tips for optimizing the process. Additionally, we describe techniques for measuring changes in arterial diameter, which is an hypothesized CSF pumping mechanism. Finally, we outline how these same techniques can be applied to cervical lymphatic vessels, which collect fluid downstream from meningeal lymphatic vessels. We anticipate that these fluid mechanical techniques will prove valuable for future quantitative studies aimed at understanding mechanisms of CSF transport and disruption, as well as for other complex biophysical systems.
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Affiliation(s)
- Daehyun Kim
- Department of Mechanical Engineering, University of Minnesota, 111 Church St SE, Minneapolis, MN, 55455, United States
| | - Yiming Gan
- Department of Mechanical Engineering, University of Rochester, Hopeman Engineering Bldg, Rochester, NY, 14627, United States
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY, 14642, United States
| | - Douglas H. Kelley
- Department of Mechanical Engineering, University of Rochester, Hopeman Engineering Bldg, Rochester, NY, 14627, United States
| | - Jeffrey Tithof
- Department of Mechanical Engineering, University of Minnesota, 111 Church St SE, Minneapolis, MN, 55455, United States
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6
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Liu JTC, Glaser AK, Poudel C, Vaughan JC. Nondestructive 3D Pathology with Light-Sheet Fluorescence Microscopy for Translational Research and Clinical Assays. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2023; 16:231-252. [PMID: 36854208 DOI: 10.1146/annurev-anchem-091222-092734] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In recent years, there has been a revived appreciation for the importance of spatial context and morphological phenotypes for both understanding disease progression and guiding treatment decisions. Compared with conventional 2D histopathology, which is the current gold standard of medical diagnostics, nondestructive 3D pathology offers researchers and clinicians the ability to visualize orders of magnitude more tissue within their natural volumetric context. This has been enabled by rapid advances in tissue-preparation methods, high-throughput 3D microscopy instrumentation, and computational tools for processing these massive feature-rich data sets. Here, we provide a brief overview of many of these technical advances along with remaining challenges to be overcome. We also speculate on the future of 3D pathology as applied in translational investigations, preclinical drug development, and clinical decision-support assays.
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Affiliation(s)
- Jonathan T C Liu
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, USA;
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Adam K Glaser
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, USA;
- Allen Institute for Neural Dynamics, Seattle, Washington, USA
| | - Chetan Poudel
- Department of Chemistry, University of Washington, Seattle, Washington, USA
| | - Joshua C Vaughan
- Department of Chemistry, University of Washington, Seattle, Washington, USA
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
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7
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Zhao C, Chen S, Zhang L, Zhang D, Wu R, Hu Y, Zeng F, Li Y, Wu D, Yu F, Zhang Y, Zhang J, Chen L, Wang A, Cheng H. Miniature three-photon microscopy maximized for scattered fluorescence collection. Nat Methods 2023; 20:617-622. [PMID: 36823329 DOI: 10.1038/s41592-023-01777-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 01/13/2023] [Indexed: 02/25/2023]
Abstract
In deep-tissue multiphoton microscopy, diffusion and scattering of fluorescent photons, rather than ballistic emanation from the focal point, have been a confounding factor. Here we report on a 2.17-g miniature three-photon microscope (m3PM) with a configuration that maximizes fluorescence collection when imaging in highly scattering regimes. We demonstrate its capability by imaging calcium activity throughout the entire cortex and dorsal hippocampal CA1, up to 1.2 mm depth, at a safe laser power. It also enables the detection of sensorimotor behavior-correlated activities of layer 6 neurons in the posterior parietal cortex in freely moving mice during single-pellet reaching tasks. Thus, m3PM-empowered imaging allows the study of neural mechanisms in deep cortex and subcortical structures, like the dorsal hippocampus and dorsal striatum, in freely behaving animals.
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Affiliation(s)
- Chunzhu Zhao
- National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China.
| | - Shiyuan Chen
- National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China
| | - Lifeng Zhang
- Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing Raygen Health, Nanjing, China
| | - Dong Zhang
- Academy of Advanced Interdisciplinary Study, Peking University, Beijing, China
| | - Runlong Wu
- National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China
| | - Yanhui Hu
- Beijing Transcend Vivoscope Biotech, Beijing, China
| | | | - Yijun Li
- Beijing Transcend Vivoscope Biotech, Beijing, China
| | - Dakun Wu
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
| | - Fei Yu
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
- Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, China
| | - Yunfeng Zhang
- School of Electronics, Peking University, Beijing, China
| | - Jue Zhang
- Academy of Advanced Interdisciplinary Study, Peking University, Beijing, China
- College of Engineering, Peking University, Beijing, China
| | - Liangyi Chen
- National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China
| | - Aimin Wang
- School of Electronics, Peking University, Beijing, China.
- State Key Laboratory of Advanced Optical Communication System and Networks, Peking University, Beijing, China.
| | - Heping Cheng
- National Biomedical Imaging Center, State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China.
- Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing Raygen Health, Nanjing, China.
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8
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Lecoq JA, Boehringer R, Grewe BF. Deep brain imaging on the move. Nat Methods 2023; 20:495-496. [PMID: 36869123 DOI: 10.1038/s41592-023-01808-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Affiliation(s)
| | - Roman Boehringer
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Benjamin F Grewe
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Zurich, Switzerland.
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9
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Xiao Y, Deng P, Zhao Y, Yang S, Li B. Three-photon excited fluorescence imaging in neuroscience: From principles to applications. Front Neurosci 2023; 17:1085682. [PMID: 36891460 PMCID: PMC9986337 DOI: 10.3389/fnins.2023.1085682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 02/02/2023] [Indexed: 02/22/2023] Open
Abstract
The development of three-photon microscopy (3PM) has greatly expanded the capability of imaging deep within biological tissues, enabling neuroscientists to visualize the structure and activity of neuronal populations with greater depth than two-photon imaging. In this review, we outline the history and physical principles of 3PM technology. We cover the current techniques for improving the performance of 3PM. Furthermore, we summarize the imaging applications of 3PM for various brain regions and species. Finally, we discuss the future of 3PM applications for neuroscience.
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Affiliation(s)
| | | | | | | | - Bo Li
- State Key Laboratory of Medical Neurobiology, Department of Neurology, Ministry of Education (MOE), Frontiers Center for Brain Science, Institute for Translational Brain Research, Huashan Hospital, Fudan University, Shanghai, China
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10
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Yu X, Zhou L, Qi T, Zhao H, Xie H. MEMS Enabled Miniature Two-Photon Microscopy for Biomedical Imaging. MICROMACHINES 2023; 14:470. [PMID: 36838170 PMCID: PMC9958604 DOI: 10.3390/mi14020470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 02/07/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Over the last decade, two-photon microscopy (TPM) has been the technique of choice for in vivo noninvasive optical brain imaging for neuroscientific study or intra-vital microendoscopic imaging for clinical diagnosis or surgical guidance because of its intrinsic capability of optical sectioning for imaging deeply below the tissue surface with sub-cellular resolution. However, most of these research activities and clinical applications are constrained by the bulky size of traditional TMP systems. An attractive solution is to develop miniaturized TPMs, but this is challenged by the difficulty of the integration of dynamically scanning optical and mechanical components into a small space. Fortunately, microelectromechanical systems (MEMS) technology, together with other emerging micro-optics techniques, has offered promising opportunities in enabling miniaturized TPMs. In this paper, the latest advancements in both lateral scan and axial scan techniques and the progress of miniaturized TPM imaging will be reviewed in detail. Miniature TPM probes with lateral 2D scanning mechanisms, including electrostatic, electromagnetic, and electrothermal actuation, are reviewed. Miniature TPM probes with axial scanning mechanisms, such as MEMS microlenses, remote-focus, liquid lenses, and deformable MEMS mirrors, are also reviewed.
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Affiliation(s)
- Xiaomin Yu
- Key Laboratory of Biological Effect of Physical Field and Instrument, Department of Electrical and Electronic Engineering, Chengdu University of Information Technology, Chengdu 610225, China
| | - Liang Zhou
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Tingxiang Qi
- BIT Chongqing Institute of Microelectronics and Microsystems, Chongqing 401332, China
| | - Hui Zhao
- BIT Chongqing Institute of Microelectronics and Microsystems, Chongqing 401332, China
- Foshan Lightview Technology Co., Ltd., Foshan 528000, China
| | - Huikai Xie
- BIT Chongqing Institute of Microelectronics and Microsystems, Chongqing 401332, China
- Foshan Lightview Technology Co., Ltd., Foshan 528000, China
- School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing 100081, China
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11
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Kučikas V, Werner MP, Schmitz-Rode T, Louradour F, van Zandvoort MAMJ. Two-Photon Endoscopy: State of the Art and Perspectives. Mol Imaging Biol 2023; 25:3-17. [PMID: 34779969 PMCID: PMC9971078 DOI: 10.1007/s11307-021-01665-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/15/2021] [Accepted: 10/05/2021] [Indexed: 10/19/2022]
Abstract
In recent years, the demand for non-destructive deep-tissue imaging modalities has led to interest in multiphoton endoscopy. In contrast to bench top systems, multiphoton endoscopy enables subcellular resolution imaging in areas not reachable before. Several groups have recently presented their development towards the goal of producing user friendly plug and play system, which could be used in biological research and, potentially, clinical applications. We first present the technological challenges, prerequisites, and solutions in two-photon endoscopic systems. Secondly, we focus on the applications already found in literature. These applications mostly serve as a quality check of the built system, but do not answer a specific biomedical research question. Therefore, in the last part, we will describe our vision on the enormous potential applicability of adult two-photon endoscopic systems in biological and clinical research. We will thus bring forward the concept that two-photon endoscopy is a sine qua non in bringing this technique to the forefront in clinical applications.
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Affiliation(s)
- Vytautas Kučikas
- Institute for Molecular Cardiovascular Research (IMCAR), RWTH Aachen University, Aachen, Germany. .,XLIM Research Institute, Limoges University, CNRS, Limoges, France.
| | - Maximilian P Werner
- Department of Biohybrid and Medical Textiles (BioTex), RWTH Aachen University, Aachen, Germany
| | - Thomas Schmitz-Rode
- Department of Biohybrid and Medical Textiles (BioTex), RWTH Aachen University, Aachen, Germany
| | | | - Marc A M J van Zandvoort
- Institute for Molecular Cardiovascular Research (IMCAR), RWTH Aachen University, Aachen, Germany.,Institute for Cardiovascular Diseases CARIM, Department of Molecular Cell Biology, Maastricht University, Maastricht, Netherlands
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12
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Beacher NJ, Washington KA, Zhang Y, Li Y, Lin DT. GRIN lens applications for studying neurobiology of substance use disorder. ADDICTION NEUROSCIENCE 2022; 4:100049. [PMID: 36531187 PMCID: PMC9757736 DOI: 10.1016/j.addicn.2022.100049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Substance use disorder (SUD) is associated with severe health and social consequences. Continued drug use results in alterations of circuits within the mesolimbic dopamine system. It is critical to observe longitudinal impacts of SUD on neural activity in vivo to identify SUD predispositions, develop pharmaceuticals to prevent overdose, and help people suffering from SUD. However, implicated SUD associated areas are buried in deep brain which makes in vivo observation of neural activity challenging. The gradient index (GRIN) lens can probe these regions in mice and rats. In this short communications review, we will discuss how the GRIN lens can be coupled with other technologies such as miniaturized microscopes, fiberscopes, fMRI, and optogenetics to fully explore in vivo SUD research. Particularly, GRIN lens allows in vivo observation of deep brain regions implicated in SUD, differentiation of genetically distinct neurons, examination of individual cells longitudinally, correlation of neuronal patters with SUD behavior, and manipulation of neural circuits.
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Affiliation(s)
- Nicholas James Beacher
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States
| | - Kayden Alecsandre Washington
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States
| | - Yan Zhang
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States
| | - Yun Li
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, United States
| | - Da-Ting Lin
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States
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13
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Barbera G, Jun R, Zhang Y, Liang B, Li Y, Lin DT. A miniature fluorescence microscope for multi-plane imaging. Sci Rep 2022; 12:16686. [PMID: 36202883 PMCID: PMC9537509 DOI: 10.1038/s41598-022-21022-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/21/2022] [Indexed: 11/16/2022] Open
Abstract
Miniature fluorescence microscopes are becoming an increasingly established tool to investigate neural circuits in freely moving animals. In this work we present a lightweight one-photon microscope capable of imaging at different focal depths. The focal plane can be changed dynamically by modulating the pulse width of the control signal to a variable focus liquid lens, which is synchronized to the image sensor to enable changing focal plane between frames. The system was tested by imaging GCaMP7f expressing neurons in the mouse medial prefrontal cortex (mPFC) in vivo during open field test. Results showed that with the proposed design it is possible to image neurons across an axial scan of ~ 60 μm, resulting in a ~ 40% increase of total neurons imaged compared to single plane imaging.
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Affiliation(s)
- Giovanni Barbera
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, USA.
| | - Rachel Jun
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Yan Zhang
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Bo Liang
- School of Electrical Engineering and Computer Science, University of North Dakota, Grand Forks, ND, 58202, USA
| | - Yun Li
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, 82071, USA
| | - Da-Ting Lin
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, USA.
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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14
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Zong W, Obenhaus HA, Skytøen ER, Eneqvist H, de Jong NL, Vale R, Jorge MR, Moser MB, Moser EI. Large-scale two-photon calcium imaging in freely moving mice. Cell 2022; 185:1240-1256.e30. [PMID: 35305313 PMCID: PMC8970296 DOI: 10.1016/j.cell.2022.02.017] [Citation(s) in RCA: 109] [Impact Index Per Article: 54.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 01/12/2022] [Accepted: 02/14/2022] [Indexed: 11/29/2022]
Abstract
We developed a miniaturized two-photon microscope (MINI2P) for fast, high-resolution, multiplane calcium imaging of over 1,000 neurons at a time in freely moving mice. With a microscope weight below 3 g and a highly flexible connection cable, MINI2P allowed stable imaging with no impediment of behavior in a variety of assays compared to untethered, unimplanted animals. The improved cell yield was achieved through a optical system design featuring an enlarged field of view (FOV) and a microtunable lens with increased z-scanning range and speed that allows fast and stable imaging of multiple interleaved planes, as well as 3D functional imaging. Successive imaging across multiple, adjacent FOVs enabled recordings from more than 10,000 neurons in the same animal. Large-scale proof-of-principle data were obtained from cell populations in visual cortex, medial entorhinal cortex, and hippocampus, revealing spatial tuning of cells in all areas.
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Affiliation(s)
- Weijian Zong
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway.
| | - Horst A Obenhaus
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
| | - Emilie R Skytøen
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
| | - Hanna Eneqvist
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
| | - Nienke L de Jong
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
| | - Ruben Vale
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
| | - Marina R Jorge
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
| | - May-Britt Moser
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway
| | - Edvard I Moser
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology (NTNU), Trondheim NO-7491, Norway.
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15
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Deep-learning two-photon fiberscopy for video-rate brain imaging in freely-behaving mice. Nat Commun 2022; 13:1534. [PMID: 35318318 PMCID: PMC8940941 DOI: 10.1038/s41467-022-29236-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 03/01/2022] [Indexed: 01/04/2023] Open
Abstract
Scanning two-photon (2P) fiberscopes (also termed endomicroscopes) have the potential to transform our understanding of how discrete neural activity patterns result in distinct behaviors, as they are capable of high resolution, sub cellular imaging yet small and light enough to allow free movement of mice. However, their acquisition speed is currently suboptimal, due to opto-mechanical size and weight constraints. Here we demonstrate significant advances in 2P fiberscopy that allow high resolution imaging at high speeds (26 fps) in freely-behaving mice. A high-speed scanner and a down-sampling scheme are developed to boost imaging speed, and a deep learning (DL) algorithm is introduced to recover image quality. For the DL algorithm, a two-stage learning transfer strategy is established to generate proper training datasets for enhancing the quality of in vivo images. Implementation enables video-rate imaging at ~26 fps, representing 10-fold improvement in imaging speed over the previous 2P fiberscopy technology while maintaining a high signal-to-noise ratio and imaging resolution. This DL-assisted 2P fiberscope is capable of imaging the arousal-induced activity changes in populations of layer2/3 pyramidal neurons in the primary motor cortex of freely-behaving mice, providing opportunities to define the neural basis of behavior. The acquisition speed of two-photon fiberscopes is currently suboptimal. Here the authors report advances, including a high-speed scanner and down-sampling scheme as well as a two-stage deep learning (DL) algorithm, to allow high-speed, high-resolution imaging in freely moving mice.
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16
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Kim TH, Schnitzer MJ. Fluorescence imaging of large-scale neural ensemble dynamics. Cell 2022; 185:9-41. [PMID: 34995519 PMCID: PMC8849612 DOI: 10.1016/j.cell.2021.12.007] [Citation(s) in RCA: 75] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 12/14/2022]
Abstract
Recent progress in fluorescence imaging allows neuroscientists to observe the dynamics of thousands of individual neurons, identified genetically or by their connectivity, across multiple brain areas and for extended durations in awake behaving mammals. We discuss advances in fluorescent indicators of neural activity, viral and genetic methods to express these indicators, chronic animal preparations for long-term imaging studies, and microscopes to monitor and manipulate the activity of large neural ensembles. Ca2+ imaging studies of neural activity can track brain area interactions and distributed information processing at cellular resolution. Across smaller spatial scales, high-speed voltage imaging reveals the distinctive spiking patterns and coding properties of targeted neuron types. Collectively, these innovations will propel studies of brain function and dovetail with ongoing neuroscience initiatives to identify new neuron types and develop widely applicable, non-human primate models. The optical toolkit's growing sophistication also suggests that "brain observatory" facilities would be useful open resources for future brain-imaging studies.
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Affiliation(s)
- Tony Hyun Kim
- James Clark Center for Biomedical Engineering & Sciences, Stanford University, Stanford, CA 94305, USA; CNC Program, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
| | - Mark J Schnitzer
- James Clark Center for Biomedical Engineering & Sciences, Stanford University, Stanford, CA 94305, USA; CNC Program, Stanford University, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
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17
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Grabarz AM, Ośmiałowski B. Benchmarking Density Functional Approximations for Excited-State Properties of Fluorescent Dyes. Molecules 2021; 26:7434. [PMID: 34946515 PMCID: PMC8703901 DOI: 10.3390/molecules26247434] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/28/2021] [Accepted: 12/04/2021] [Indexed: 12/05/2022] Open
Abstract
This study presents an extensive analysis of the predictive power of time-dependent density functional theory in determining the excited-state properties of two groups of important fluorescent dyes, difluoroboranes and hydroxyphenylimidazo[1,2-a]pyridine derivatives. To ensure statistically meaningful results, the data set is comprised of 85 molecules manifesting diverse photophysical properties. The vertical excitation energies and dipole moments (in the electronic ground and excited states) of the aforementioned dyes were determined using the RI-CC2 method (reference) and with 18 density functional approximations (DFA). The set encompasses DFAs with varying amounts of exact exchange energy (EEX): from 0% (e.g., SVWN, BLYP), through a medium (e.g., TPSSh, B3LYP), up to a major contribution of EEX (e.g., BMK, MN15). It also includes range-separated hybrids (CAM-B3LYP, LC-BLYP). Similar error profiles of vertical energy were obtained for both dye groups, although the errors related to hydroxyphenylimidazopiridines are significantly larger. Overall, functionals including 40-55% of EEX (SOGGA11-X, BMK, M06-2X) ensure satisfactory agreement with the reference vertical excitation energies obtained using the RI-CC2 method; however, MN15 significantly outperforms them, providing a mean absolute error of merely 0.04 eV together with a very high correlation coefficient (R2 = 0.98). Within the investigated set of functionals, there is no single functional that would equally accurately determine ground- and excited-state dipole moments of difluoroboranes and hydroxyphenylimidazopiridine derivatives. Depending on the chosen set of dyes, the most accurate μGS predictions were delivered by MN15 incorporating a major EEX contribution (difluoroboranes) and by PBE0 containing a minor EEX fraction (hydroxyphenylimidazopiridines). Reverse trends are observed for μES, i.e., for difluoroboranes the best results were obtained with functionals including a minor fraction of EEX, specifically PBE0, while in the case of hydroxyphenylimidazopiridines, much more accurate predictions were provided by functionals incorporating a major EEX contribution (BMK, MN15).
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Affiliation(s)
- Anna M. Grabarz
- Faculty of Chemistry, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, PL-50370 Wrocław, Poland
| | - Borys Ośmiałowski
- Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, PL-87100 Toruń, Poland;
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18
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Guan H, Liang W, Li A, Gau YTA, Chen D, Li MJ, Bergles DE, Li X. Multicolor fiber-optic two-photon endomicroscopy for brain imaging. OPTICS LETTERS 2021; 46:1093-1096. [PMID: 33649665 PMCID: PMC11214692 DOI: 10.1364/ol.412760] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/26/2021] [Indexed: 06/12/2023]
Abstract
Visualizing activity patterns of distinct cell types during complex behaviors is essential to understand complex neural networks. It remains challenging to excite multiple fluorophores simultaneously so that different types of neurons can be imaged. In this Letter, we report a multicolor fiber-optic two-photon endomicroscopy platform in which two pulses from a Ti:sapphire laser and an optical parametric oscillator were synchronized and delivered through a single customized double-clad fiber to excite multiple chromophores. A third virtual wavelength could also be generated by spatial-temporal overlapping of the two pulses. The performance of the fiber-optic multicolor two-photon endomicroscope was demonstrated by in vivo imaging of a mouse cerebral cortex with "Brainbow" labeling.
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Affiliation(s)
- Honghua Guan
- Department of Electrical and Computer Engineering, Johns Hopkins University, Maryland 21218, USA
| | - Wenxuan Liang
- Department of Biomedical Engineering, Johns Hopkins University, Maryland 21205, USA
| | - Ang Li
- Department of Biomedical Engineering, Johns Hopkins University, Maryland 21205, USA
| | - Yung-Tian A. Gau
- Department of Neuroscience, Johns Hopkins University, Maryland 21205, USA
| | - Defu Chen
- Department of Biomedical Engineering, Johns Hopkins University, Maryland 21205, USA
| | - Ming-Jun Li
- Science and Technology Division, Corning Incorporated, Corning, New York 14831, USA
| | - Dwight E. Bergles
- Department of Neuroscience, Johns Hopkins University, Maryland 21205, USA
| | - Xingde Li
- Department of Electrical and Computer Engineering, Johns Hopkins University, Maryland 21218, USA
- Department of Biomedical Engineering, Johns Hopkins University, Maryland 21205, USA
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19
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Multimodal Functional Analysis Platform: 1. Ultrathin Fluorescence Endoscope Imaging System Enables Flexible Functional Brain Imaging. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1293:471-479. [PMID: 33398834 DOI: 10.1007/978-981-15-8763-4_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
To elucidate the expression mechanisms of brain functions, we have developed an ultrathin fluorescence endoscope imaging system (U-FEIS) that can image cells in the brain at any depth while minimizing the invasion. The endoscope part of U-FEIS consists of a GRIN lens and a 10,000-pixel image fiber with a diameter of 450 μm. The specialized microscope of U-FEIS is within 30 cm square and includes lenses and optical filters optimized for the endoscope. Using U-FEIS, we successfully visualized neurons expressing GFP with single-cell resolution and recorded the multineuronal activities in vitro and in vivo. U-FEIS can also perform imaging and optical stimulation simultaneously. Therefore, U-FEIS should be a powerful optical tool in neuroscience research.
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20
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Zong W, Wu R, Chen S, Wu J, Wang H, Zhao Z, Chen G, Tu R, Wu D, Hu Y, Xu Y, Wang Y, Duan Z, Wu H, Zhang Y, Zhang J, Wang A, Chen L, Cheng H. Miniature two-photon microscopy for enlarged field-of-view, multi-plane and long-term brain imaging. Nat Methods 2021; 18:46-49. [PMID: 33408404 DOI: 10.1038/s41592-020-01024-z] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 11/23/2020] [Indexed: 12/11/2022]
Abstract
We have developed a miniature two-photon microscope equipped with an axial scanning mechanism and a long-working-distance miniature objective to enable multi-plane imaging over a volume of 420 × 420 × 180 μm3 at a lateral resolution of ~1 μm. Together with the detachable design that permits long-term recurring imaging, our miniature two-photon microscope can help decipher neuronal mechanisms in freely behaving animals.
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Affiliation(s)
- Weijian Zong
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China.,Department of Cognitive Sciences, Institute of Basic Medical Sciences, Beijing, China.,Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Runlong Wu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China.
| | - Shiyuan Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China
| | - Junjie Wu
- College of Engineering, Peking University, Beijing, China
| | - Hanbin Wang
- Academy of Advanced Interdisciplinary Study, Peking University, Beijing, China
| | - Zhe Zhao
- Department of Neurobiology, Institute of Basic Medical Sciences, Beijing, China
| | - Guoqing Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China
| | - Rui Tu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China
| | - Danlei Wu
- Beijing Transcend Vivoscope Biotech Co., Ltd, Beijing, China
| | - Yanhui Hu
- Beijing Transcend Vivoscope Biotech Co., Ltd, Beijing, China
| | - Yangyang Xu
- Beijing Transcend Vivoscope Biotech Co., Ltd, Beijing, China
| | - Yao Wang
- Academy of Advanced Interdisciplinary Study, Peking University, Beijing, China
| | - Zhuoli Duan
- Department of Neurology, Southern Medical University, Guangzhou, China
| | - Haitao Wu
- Department of Neurobiology, Institute of Basic Medical Sciences, Beijing, China
| | - Yunfeng Zhang
- Department of Electronics, Peking University, Beijing, China
| | - Jue Zhang
- College of Engineering, Peking University, Beijing, China.,Academy of Advanced Interdisciplinary Study, Peking University, Beijing, China
| | - Aimin Wang
- Department of Electronics, Peking University, Beijing, China. .,State Key Laboratory of Advanced Optical Communication System and Networks, Peking University, Beijing, China.
| | - Liangyi Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China. .,PKU-IDG/McGovern Institute for Brain Research, Beijing, China. .,Beijing Academy of Artificial Intelligence, Beijing, China.
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, College of Future Technology, Peking University, Beijing, China.,Research Unit of Mitochondria in Brain Diseases, Chinese Academy of Medical Sciences, PKU-Nanjing Institute of Translational Medicine, Nanjing, China
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21
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Liang W, Park HC, Li K, Li A, Chen D, Guan H, Yue Y, Gau YTA, Bergles DE, Li MJ, Lu H, Li X. Throughput-Speed Product Augmentation for Scanning Fiber-Optic Two-Photon Endomicroscopy. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:3779-3787. [PMID: 32746124 PMCID: PMC7773217 DOI: 10.1109/tmi.2020.3005067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Compactness, among several others, is one unique and very attractive feature of a scanning fiber-optic two-photon endomicroscope. To increase the scanning area and the total number of resolvable pixels (i.e., the imaging throughput), it typically requires a longer cantilever which, however, leads to a much undesired, reduced scanning speed (and thus imaging frame rate). Herein we introduce a new design strategy for a fiber-optic scanning endomicroscope, where the overall numerical aperture (NA) or beam focusing power is distributed over two stages: 1) a mode-field focuser engineered at the tip of a double-clad fiber (DCF) cantilever to pre-amplify the single-mode core NA, and 2) a micro objective of a lower magnification (i.e., ∼ 2× in this design) to achieve final tight beam focusing. This new design enables either an ~9-fold increase in imaging area (throughput) or an ~3-fold improvement in imaging frame rate when compared to traditional fiber-optic endomicroscope designs. The performance of an as-designed endomicroscope of an enhanced throughput-speed product was demonstrated by two representative applications: (1) high-resolution imaging of an internal organ (i.e., mouse kidney) in vivo over a large field of view without using any fluorescent contrast agents, and (2) real-time neural imaging by visualizing dendritic calcium dynamics in vivo with sub-second temporal resolution in GCaMP6m-expressing mouse brain. This cascaded NA amplification strategy is universal and can be readily adapted to other types of fiber-optic scanners in compact linear or nonlinear endomicroscopes.
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22
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Wang B, Zhang Q, Chen X, Luan H, Gu M. Perspective of fibre-optical microendoscopy with microlenses. J Microsc 2020; 288:87-94. [PMID: 33169362 DOI: 10.1111/jmi.12977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/29/2020] [Accepted: 10/29/2020] [Indexed: 11/27/2022]
Abstract
Fibre-optical microendoscopy is based on fibre-optical confocal scanning microscopy, where optical fibres are introduced for delivery of the source and collection of the signal. Fibre-optical microendoscopy has led to innovations in imaging of freely moving animals, long-term imaging, minimally invasive diagnostics, and microsurgery. The lens system in fibre-optical microendoscopy is significant because of the imaging resolution and miniaturisation possibility. State-of-the-art fibre-optical microendoscopy based on various types of lens systems is introduced and compared. The lens system contains an objective lens, a gradient index microlens, and other novel lens systems fabricated by electric arc discharge or two-photon lithography.
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Affiliation(s)
- Baokai Wang
- Laboratory of Artificial-Intelligence Nanophotonics, School of Science, RMIT University, Melbourne, Victoria, Australia
| | - Qiming Zhang
- Centre for Artificial-Intelligence Nanophotonics, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Xi Chen
- Centre for Artificial-Intelligence Nanophotonics, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Haitao Luan
- Centre for Artificial-Intelligence Nanophotonics, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Min Gu
- Laboratory of Artificial-Intelligence Nanophotonics, School of Science, RMIT University, Melbourne, Victoria, Australia.,Centre for Artificial-Intelligence Nanophotonics, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai, China
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23
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Chen S, Wang Z, Zhang D, Wang A, Chen L, Cheng H, Wu R. Miniature Fluorescence Microscopy for Imaging Brain Activity in Freely-Behaving Animals. Neurosci Bull 2020; 36:1182-1190. [PMID: 32797396 PMCID: PMC7532237 DOI: 10.1007/s12264-020-00561-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/11/2020] [Indexed: 12/11/2022] Open
Abstract
An ultimate goal of neuroscience is to decipher the principles underlying neuronal information processing at the molecular, cellular, circuit, and system levels. The advent of miniature fluorescence microscopy has furthered the quest by visualizing brain activities and structural dynamics in animals engaged in self-determined behaviors. In this brief review, we summarize recent advances in miniature fluorescence microscopy for neuroscience, focusing mostly on two mainstream solutions - miniature single-photon microscopy, and miniature two-photon microscopy. We discuss their technical advantages and limitations as well as unmet challenges for future improvement. Examples of preliminary applications are also presented to reflect on a new trend of brain imaging in experimental paradigms involving body movements, long and complex protocols, and even disease progression and aging.
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Affiliation(s)
- Shiyuan Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, PKU-Nanjing Institute of Translational Medicine, Peking University, Beijing, 100871, China
| | - Zichen Wang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, PKU-Nanjing Institute of Translational Medicine, Peking University, Beijing, 100871, China
| | - Dong Zhang
- Academy of Advanced Interdisciplinary Study, Peking University, Beijing, 100871, China
| | - Aiming Wang
- Department of Electronics, Peking University, Beijing, 100871, China
- State Key Laboratory of Advanced Optical Communication System and Networks, Peking University, Beijing, 100871, China
| | - Liangyi Chen
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, PKU-Nanjing Institute of Translational Medicine, Peking University, Beijing, 100871, China
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, PKU-Nanjing Institute of Translational Medicine, Peking University, Beijing, 100871, China
| | - Runlong Wu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, PKU-Nanjing Institute of Translational Medicine, Peking University, Beijing, 100871, China.
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24
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Endoscopic Optical Imaging Technologies and Devices for Medical Purposes: State of the Art. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10196865] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The growth and development of optical components and, in particular, the miniaturization of micro-electro-mechanical systems (MEMSs), has motivated and enabled researchers to design smaller and smaller endoscopes. The overarching goal of this work has been to image smaller previously inaccessible luminal organs in real time, at high resolution, in a minimally invasive manner that does not compromise the comfort of the subject, nor introduce additional risk. Thus, an initial diagnosis can be made, or a small precancerous lesion may be detected, in a small-diameter luminal organ that would not have otherwise been possible. Continuous advancement in the field has enabled a wide range of optical scanners. Different scanning techniques, working principles, and the applications of endoscopic scanners are summarized in this review.
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25
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Zhou L, Yu X, Feng PXL, Li J, Xie H. A MEMS lens scanner based on serpentine electrothermal bimorph actuators for large axial tuning. OPTICS EXPRESS 2020; 28:23439-23453. [PMID: 32752341 PMCID: PMC7470678 DOI: 10.1364/oe.400363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Confocal microscopes and two-photon microscopes are powerful tools for early cancer diagnosis because of their high-resolution 3D imaging capability, but applying them for clinical use in internal organs is hindered by the lack of axially tunable lens modules with small size, high image quality and large tuning range. This paper reports a compact MEMS lens scanner that has the potential to overcome this limitation. The MEMS lens scanner consists of a MEMS microstage and a microlens. The MEMS microstage is based on a unique serpentine inverted-series-connected (ISC) electrothermal bimorph actuator design. The microlens is an aspheric glass lens to ensure optical quality. The MEMS microstage has been fabricated and the lens scanner has been successfully assembled. The entire lens scanner is circular with an outer diameter of 4.4 mm and a clear optical aperture of 1.8 mm. Experiments show that the tunable range reaches over 200 µm at only 10.5 V and the stiffness of the microstage is 6.2 N/m. Depth scan imaging by the MEMS lens scanner has also been demonstrated with a 2.2 µm resolution, only limited by the available resolution target.
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Affiliation(s)
- Liang Zhou
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Xiaomin Yu
- College of Electronic Engineering, Chengdu University of Information Technology, Chengdu 610225, Sichuan, China
| | - Philip X.-L. Feng
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Jianhua Li
- School of Mechatronical Engineering, Beijing Institute of Technology, 100081 Beijing, China
| | - Huikai Xie
- School of Information and Electronics, Beijing Institute of Technology, 100081 Beijing, China
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26
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Zhou G, Lim ZH, Qi Y, Zhou G. Single-Pixel MEMS Imaging Systems. MICROMACHINES 2020; 11:E219. [PMID: 32093324 PMCID: PMC7074650 DOI: 10.3390/mi11020219] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 11/16/2022]
Abstract
Single-pixel imaging technology is an attractive technology considering the increasing demand of imagers that can operate in wavelengths where traditional cameras have limited efficiency. Meanwhile, the miniaturization of imaging systems is also desired to build affordable and portable devices for field applications. Therefore, single-pixel imaging systems based on microelectromechanical systems (MEMS) is an effective solution to develop truly miniaturized imagers, owing to their ability to integrate multiple functionalities within a small device. MEMS-based single-pixel imaging systems have mainly been explored in two research directions, namely the encoding-based approach and the scanning-based approach. The scanning method utilizes a variety of MEMS scanners to scan the target scenery and has potential applications in the biological imaging field. The encoding-based system typically employs MEMS modulators and a single-pixel detector to encode the light intensities of the scenery, and the images are constructed by harvesting the power of computational technology. This has the capability to capture non-visible images and 3D images. Thus, this review discusses the two approaches in detail, and their applications are also reviewed to evaluate the efficiency and advantages in various fields.
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Affiliation(s)
- Guangcan Zhou
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
| | - Zi Heng Lim
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
| | - Yi Qi
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
| | - Guangya Zhou
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
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27
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A Dual Hollow Core Antiresonant Optical Fiber Coupler Based on a Highly Birefringent Structure-Numerical Design and Analysis. FIBERS 2019. [DOI: 10.3390/fib7120109] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
With the growing interest in hollow-core antiresonant fibers (HC-ARF), attributed to the development of their fabrication technology, the appearance of more sophisticated structures is understandable. One of the recently advancing concepts is that of dual hollow-core antiresonant fibers, which have the potential to be used as optical fiber couplers. In the following paper, a design of a dual hollow-core antiresonant fiber (DHC-ARF) acting as a polarization fiber coupler is presented. The structure is based on a highly birefringent hollow-core fiber design, which is proven to be a promising solution for the purpose of propagation of polarized signals. The design of an optimized DHC-ARF with asymmetrical cores is proposed, together with analysis of its essential coupling parameters, such as the extinction ratio, coupling length ratio, and coupling strength. The latter two for the x- and y-polarized signals were ~2 and 1, respectively, while the optical losses were below 0.3 dB/cm in the 1500–1700 nm transmission band.
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28
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Heffernan BM, Meyer SA, Restrepo D, Siemens ME, Gibson EA, Gopinath JT. A Fiber-Coupled Stimulated Emission Depletion Microscope for Bend-Insensitive Through-Fiber Imaging. Sci Rep 2019; 9:11137. [PMID: 31366899 PMCID: PMC6668468 DOI: 10.1038/s41598-019-47319-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/15/2019] [Indexed: 01/27/2023] Open
Abstract
We present results for a new type of fiber-coupled stimulated emission depletion (STED) microscope which uses a single fiber to transport STED and excitation light, as well as collect the fluorescence signal. Our method utilizes two higher-order eigenmodes of polarization maintaining (PM) fiber to generate the doughnut-shaped STED beam. The modes are excited with separate beams that share no temporal coherence, yielding output that is independent of fiber bending. We measured the resolution using 45 nm fluorescent beads and found a median bead image size of 116 nm. This resolution does not change as function of fiber bending radius, demonstrating robust operation. We report, for the first time, STED images of fixed biological samples collected in the epi-direction through fiber. Our microscope design shows promise for future use in super-resolution micro-endoscopes and in vivo neural imaging in awake and freely-behaving animals.
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Affiliation(s)
- Brendan M Heffernan
- Department of Physics, University of Colorado Boulder, Boulder, CO, 80309, USA.
| | - Stephanie A Meyer
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Diego Restrepo
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Mark E Siemens
- Department of Physics and Astronomy, University of Denver, Denver, CO, 80210, USA
| | - Emily A Gibson
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Juliet T Gopinath
- Department of Physics, University of Colorado Boulder, Boulder, CO, 80309, USA
- Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Boulder, CO, 80309, USA
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Xi G, Cao N, Guo W, Kang D, Chen Z, He J, Ren W, Shen T, Wang C, Chen J. Label-Free Imaging of Blood Vessels in Human Normal Breast and Breast Tumor Tissue Using Multiphoton Microscopy. SCANNING 2019; 2019:5192875. [PMID: 31341525 PMCID: PMC6614986 DOI: 10.1155/2019/5192875] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/19/2019] [Accepted: 05/29/2019] [Indexed: 05/29/2023]
Abstract
Blood vessels are the important components of the circulatory systems that transport blood throughout the human body and maintain the homeostasis of physiological tissues. Pathologically, blood vessels are often affected by diseases, leading to the formation of unstable, irregular, and hyperpermeable blood vessels. In the tumor microenvironment, abnormal leakage of tumor blood vessels is related to the histological grade and malignant potential of tumors and may also facilitate metastasis of cancer. Visual diagnosis of blood vessels is very important for us to understand the occurrence and development of diseases. Multiphoton microscopy (MPM) is a potential label-free diagnostic tool based on second harmonic generation (SHG) and two-photon excited fluorescence (TPEF). MPM can effectively observe the morphological changes of biological tissues at the molecular and cellular levels. In this work, we demonstrate that label-free MPM can be used to visualize the microstructure of blood vessels in human normal breast and breast tumor tissue. Moreover, MPM can monitor the changes of blood vessels in tumor microenvironment. These results show that the MPM will become a promising technique for clinicians to study the properties of the microstructure of the blood vessels.
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MESH Headings
- Blood Vessels/diagnostic imaging
- Blood Vessels/pathology
- Breast Neoplasms/blood supply
- Breast Neoplasms/diagnostic imaging
- Breast Neoplasms/pathology
- Breast Neoplasms/surgery
- Eosine Yellowish-(YS)
- Female
- Hematoxylin
- Humans
- Mammary Glands, Human/blood supply
- Mammary Glands, Human/diagnostic imaging
- Mammary Glands, Human/pathology
- Mammary Glands, Human/surgery
- Mastectomy
- Microscopy, Fluorescence, Multiphoton/instrumentation
- Microscopy, Fluorescence, Multiphoton/methods
- Neovascularization, Pathologic/diagnostic imaging
- Neovascularization, Pathologic/pathology
- Neovascularization, Pathologic/surgery
- Paraffin Embedding
- Tissue Fixation
- Tumor Microenvironment
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Affiliation(s)
- Gangqin Xi
- Key Laboratory of Optoelectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Ning Cao
- Department of Plastic Surgery, Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, 363000 Fujian, China
| | - Wenhui Guo
- Department of Breast Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Deyong Kang
- Department of Pathology, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Zhong Chen
- Key Laboratory of Optoelectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Jiajia He
- Key Laboratory of Optoelectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Wenjiao Ren
- Key Laboratory of Optoelectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Tingfeng Shen
- Key Laboratory of Optoelectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Chuan Wang
- Department of Breast Surgery, Fujian Medical University Union Hospital, Fuzhou 350001, China
| | - Jianxin Chen
- Key Laboratory of Optoelectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
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Yang H, Wang D, Shan T, Dai X, Xie H, Yang L, Jiang H. Miniature fluorescence molecular tomography (FMT) endoscope based on a MEMS scanning mirror and an optical fiberscope. Phys Med Biol 2019; 64:125015. [PMID: 31117059 DOI: 10.1088/1361-6560/ab23b3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We present a novel FMT endoscope by using a MEMS scanning mirror and an optical fiberscope. The diameter of this highly miniaturized FMT device is only 5 mm. To our knowledge, this is the smallest FMT device we found so far. Several phantom experiments based on indocyanine green (ICG) were conducted to demonstrate the imaging ability of this device. Two tumor-bearing mice were systematically injected with tumor-targeted NIR fluorescent probes (ATF-PEG-IO-830) and were then imaged to further demonstrate the ability of this FMT endoscope for imaging small animals.
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Affiliation(s)
- Hao Yang
- Department of Medical Engineering, University of South Florida, Tampa, FL, United States of America. Author to whom any correspondence should be addressed
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31
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Nelson NA, Wang X, Cook D, Carey EM, Nimmerjahn A. Imaging spinal cord activity in behaving animals. Exp Neurol 2019; 320:112974. [PMID: 31175843 DOI: 10.1016/j.expneurol.2019.112974] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/02/2019] [Accepted: 06/04/2019] [Indexed: 01/06/2023]
Abstract
The spinal cord is the primary neurological link between the brain and peripheral organs. How important it is in everyday life is apparent in patients with spinal cord injury or motoneuron disease, who have dramatically reduced musculoskeletal control or capacity to sense their environment. Despite its crucial role in sensory and motor processing little is known about the cellular and molecular signaling events that underlie spinal cord function under naturalistic conditions. While genetic, electrophysiological, pharmacological, and circuit tracing studies have revealed important roles for different molecularly defined neurons, these approaches insufficiently describe the moment-to-moment neuronal and non-neuronal activity patterns that underlie sensory-guided motor behaviors in health and disease. The recent development of imaging methods for real-time interrogation of cellular activity in the spinal cord of behaving mice has removed longstanding technical obstacles to spinal cord research and allowed new insight into how different cell types encode sensory information from mechanoreceptors and nociceptors in the skin. Here, we review the current state-of-the-art in interrogating cellular and microcircuit function in the spinal cord of behaving mammals and discuss current opportunities and technological challenges.
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Affiliation(s)
- Nicholas A Nelson
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Biologial Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92037, USA
| | - Xiang Wang
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Daniela Cook
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Erin M Carey
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Axel Nimmerjahn
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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32
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Zhou L, Zhang X, Xie H. An Electrothermal Cu/W Bimorph Tip-Tilt-Piston MEMS Mirror with High Reliability. MICROMACHINES 2019; 10:E323. [PMID: 31091696 PMCID: PMC6563100 DOI: 10.3390/mi10050323] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/05/2019] [Accepted: 05/09/2019] [Indexed: 12/04/2022]
Abstract
This paper presents the design, fabrication, and characterization of an electrothermal MEMS mirror with large tip, tilt and piston scan. This MEMS mirror is based on electrothermal bimorph actuation with Cu and W thin-film layers forming the bimorphs. The MEMS mirror is fabricated via a combination of surface and bulk micromachining. The piston displacement and tip-tilt optical angle of the mirror plate of the fabricated MEMS mirror are around 114 μm and ±8°, respectively at only 2.35 V. The measured response time is 7.3 ms. The piston and tip-tilt resonant frequencies are measured to be 1.5 kHz and 2.7 kHz, respectively. The MEMS mirror survived 220 billion scanning cycles with little change of its scanning characteristics, indicating that the MEMS mirror is stable and reliable.
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Affiliation(s)
- Liang Zhou
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA.
| | - Xiaoyang Zhang
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA.
| | - Huikai Xie
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA.
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33
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2D Au-Coated Resonant MEMS Scanner for NIR Fluorescence Intraoperative Confocal Microscope. MICROMACHINES 2019; 10:mi10050295. [PMID: 31052229 PMCID: PMC6562488 DOI: 10.3390/mi10050295] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 04/22/2019] [Accepted: 04/26/2019] [Indexed: 02/06/2023]
Abstract
The electrostatic MEMS scanner plays an important role in the miniaturization of the microscopic imaging system. We have developed a new two-dimensional (2D) parametrically-resonant MEMS scanner with patterned Au coating (>90% reflectivity at an NIR 785-nm wavelength), for a near-infrared (NIR) fluorescence intraoperative confocal microscopic imaging system with a compact form factor. A silicon-on-insulator (SOI)-wafer based dicing-free microfabrication process has been developed for mass-production with high yield. Based on an in-plane comb-drive configuration, the resonant MEMS scanner performs 2D Lissajous pattern scanning with a large mechanical scanning angle (MSA, ±4°) on each axis at low driving voltage (36 V). A large field-of-view (FOV) has been achieved by using a post-objective scanning architecture of the confocal microscope. We have integrated the new MEMS scanner into a custom-made NIR fluorescence intraoperative confocal microscope with an outer diameter of 5.5 mm at its distal-end. Axial scanning has been achieved by using a piezoelectric actuator-based driving mechanism. We have successfully demonstrated ex vivo 2D imaging on human tissue specimens with up to five frames/s. The 2D resonant MEMS scanner can potentially be utilized for many applications, including multiphoton microendoscopy and wide-field endoscopy.
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Kim DY, Hwang K, Ahn J, Seo YH, Kim JB, Lee S, Yoon JH, Kong E, Jeong Y, Jon S, Kim P, Jeong KH. Lissajous Scanning Two-photon Endomicroscope for In vivo Tissue Imaging. Sci Rep 2019; 9:3560. [PMID: 30837501 PMCID: PMC6401070 DOI: 10.1038/s41598-019-38762-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 12/31/2018] [Indexed: 12/13/2022] Open
Abstract
An endomicroscope opens new frontiers of non-invasive biopsy for in vivo imaging applications. Here we report two-photon laser scanning endomicroscope for in vivo cellular and tissue imaging using a Lissajous fiber scanner. The fiber scanner consists of a piezoelectric (PZT) tube, a single double-clad fiber (DCF) with high fluorescence collection, and a micro-tethered-silicon-oscillator (MTSO) for the separation of biaxial resonant scanning frequencies. The endomicroscopic imaging exhibits 5 frames/s with 99% in scanning density by using the selection rule of scanning frequencies. The endomicroscopic scanner was compactly packaged within a stainless tube of 2.6 mm in diameter with a high NA gradient-index (GRIN) lens, which can be easily inserted into the working channel of a conventional laparoscope. The lateral and axial resolutions of the endomicroscope are 0.70 µm and 7.6 μm, respectively. Two-photon fluorescence images of a stained kidney section and miscellaneous ex vivo and in vivo organs from wild type and green fluorescent protein transgenic (GFP-TG) mice were successfully obtained by using the endomicroscope. The endomicroscope also obtained label free images including autofluorescence and second-harmonic generation of an ear tissue of Thy1-GCaMP6 (GP5.17) mouse. The Lissajous scanning two-photon endomicroscope can provide a compact handheld platform for in vivo tissue imaging or optical biopsy applications.
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Affiliation(s)
- Daniel Youngsuk Kim
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Kyungmin Hwang
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Jinhyo Ahn
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Yeong-Hyeon Seo
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Jae-Beom Kim
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Soyoung Lee
- Department of Biological Sciences, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute for the BioCentury, Daejeon, 34141, Republic of Korea
| | - Jin-Hui Yoon
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Eunji Kong
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Yong Jeong
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Sangyong Jon
- Department of Biological Sciences, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute for the BioCentury, Daejeon, 34141, Republic of Korea
| | - Pilhan Kim
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Ki-Hun Jeong
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea. .,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea.
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35
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MEMS Actuators for Optical Microendoscopy. MICROMACHINES 2019; 10:mi10020085. [PMID: 30682852 PMCID: PMC6412441 DOI: 10.3390/mi10020085] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/26/2018] [Accepted: 12/28/2018] [Indexed: 01/21/2023]
Abstract
Growing demands for affordable, portable, and reliable optical microendoscopic imaging devices are attracting research institutes and industries to find new manufacturing methods. However, the integration of microscopic components into these subsystems is one of today's challenges in manufacturing and packaging. Together with this kind of miniaturization more and more functional parts have to be accommodated in ever smaller spaces. Therefore, solving this challenge with the use of microelectromechanical systems (MEMS) fabrication technology has opened the promising opportunities in enabling a wide variety of novel optical microendoscopy to be miniaturized. MEMS fabrication technology enables abilities to apply batch fabrication methods with high-precision and to include a wide variety of optical functionalities to the optical components. As a result, MEMS technology has enabled greater accessibility to advance optical microendoscopy technology to provide high-resolution and high-performance imaging matching with traditional table-top microscopy. In this review the latest advancements of MEMS actuators for optical microendoscopy will be discussed in detail.
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36
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Liu T, Rajadhyaksha M, Dickensheets DL. MEMS-in-the-lens architecture for a miniature high-NA laser scanning microscope. LIGHT, SCIENCE & APPLICATIONS 2019; 8:59. [PMID: 31263558 PMCID: PMC6592906 DOI: 10.1038/s41377-019-0167-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/24/2019] [Accepted: 05/30/2019] [Indexed: 05/16/2023]
Abstract
Laser scanning microscopes can be miniaturized for in vivo imaging by substituting optical microelectromechanical system (MEMS) devices in place of larger components. The emergence of multifunctional active optical devices can support further miniaturization beyond direct component replacement because those active devices enable diffraction-limited performance using simpler optical system designs. In this paper, we propose a catadioptric microscope objective lens that features an integrated MEMS device for performing biaxial scanning, axial focus adjustment, and control of spherical aberration. The MEMS-in-the-lens architecture incorporates a reflective MEMS scanner between a low-numerical-aperture back lens group and an aplanatic hyperhemisphere front refractive element to support high-numerical-aperture imaging. We implemented this new optical system using a recently developed hybrid polymer/silicon MEMS three-dimensional scan mirror that features an annular aperture that allows it to be coaxially aligned within the objective lens without the need for a beam splitter. The optical performance of the active catadioptric system is simulated and imaging of hard targets and human cheek cells is demonstrated with a confocal microscope that is based on the new objective lens design.
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Affiliation(s)
- Tianbo Liu
- Electrical and Computer Engineering Department, Montana State University, Bozeman, MT 59715 USA
| | - Milind Rajadhyaksha
- Dermatology Department, Memorial Sloan Kettering Cancer Center, New York, NY 10022 USA
| | - David L. Dickensheets
- Electrical and Computer Engineering Department, Montana State University, Bozeman, MT 59715 USA
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37
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Aharoni D, Khakh BS, Silva AJ, Golshani P. All the light that we can see: a new era in miniaturized microscopy. Nat Methods 2019; 16:11-13. [PMID: 30573833 PMCID: PMC8320687 DOI: 10.1038/s41592-018-0266-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
One major challenge in neuroscience is to uncover how defined neural circuits in the brain encode, store, modify, and retrieve information. Meeting this challenge comprehensively requires tools capable of recording and manipulating the activity of intact neural networks in naturally behaving animals. Head-mounted miniature microscopes are emerging as a key tool to address this challenge. Here we discuss recent work leading to the miniaturization of neural imaging tools, the current state of the art in this field, and the importance and necessity of open-source options. We finish with a discussion on what the future may hold for miniature microscopy.
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Affiliation(s)
- Daniel Aharoni
- Department of Neurology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, CA, USA.
| | - Baljit S Khakh
- Departments of Physiology & Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | - Alcino J Silva
- Departments of Neurobiology and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, CA, USA
- Department of Psychiatry & Biobehavioral Sciences, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, CA, USA
| | - Peyman Golshani
- Department of Neurology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, CA, USA
- Department of Psychiatry & Biobehavioral Sciences, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, CA, USA
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38
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Huang L, Zhou X, Tang S. Optimization of frequency-doubled Er-doped fiber laser for miniature multiphoton endoscopy. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-12. [PMID: 30574695 DOI: 10.1117/1.jbo.23.12.126503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 11/26/2018] [Indexed: 05/18/2023]
Abstract
Frequency-doubled femtosecond Er-doped fiber laser is a low-cost and portable excitation source suitable for multiphoton endoscopy. The frequency-doubled wavelength at 780 nm is used to excite the intrinsic fluorescence signal. The frequency-doubling with a periodically poled MgO : LiNbO3 (PPLN) is integrated in the distal end of the imaging head to achieve fiber connection. The imaging speed is further improved by optimizing the excitation laser source. A 0.3-mm length of PPLN crystal is selected and the Er-doped fiber laser is manipulated to match its bandwidth with the acceptance bandwidth of the PPLN. Through this optimization, a reduced pulsewidth of 80 fs of the frequency-doubled pulse is achieved. All-fiber dispersion compensation and pulse compression by single mode fiber is conducted, which makes the fiber laser directly fiber-coupled to the imaging head. An imaging speed of 4 frames / s is demonstrated on ex vivo imaging of unstained biological tissues, which is 10 times faster than our previous study using a 1-mm-long PPLN. The results show that miniature multiphoton endoscopy using frequency-doubled Er-doped fiber laser has great potential for clinical applications.
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Affiliation(s)
- Lin Huang
- University of British Columbia, Department of Electrical and Computer Engineering, Vancouver, Canada
| | - Xin Zhou
- University of British Columbia, Department of Electrical and Computer Engineering, Vancouver, Canada
| | - Shuo Tang
- University of British Columbia, Department of Electrical and Computer Engineering, Vancouver, Canada
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39
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Arbabi E, Li J, Hutchins RJ, Kamali SM, Arbabi A, Horie Y, Van Dorpe P, Gradinaru V, Wagenaar DA, Faraon A. Two-Photon Microscopy with a Double-Wavelength Metasurface Objective Lens. NANO LETTERS 2018; 18:4943-4948. [PMID: 30016110 DOI: 10.1021/acs.nanolett.8b01737] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Two-photon microscopy is a key imaging technique in life sciences due to its superior deep-tissue imaging capabilities. Light-weight and compact two-photon microscopes are of great interest because of their applications for in vivo deep brain imaging. Recently, dielectric metasurfaces have enabled a new category of small and lightweight optical elements, including objective lenses. Here we experimentally demonstrate two-photon microscopy using a double-wavelength metasurface lens. It is specifically designed to focus 820 and 605 nm light, corresponding to the excitation and emission wavelengths of the measured fluorophors, to the same focal distance. The captured two-photon images are qualitatively comparable to the ones taken by a conventional objective lens. Our metasurface lens can enable ultracompact two-photon microscopes with similar performance compared to current systems that are usually based on graded-index-lenses. In addition, further development of tunable metasurface lenses will enable fast axial scanning for volumetric imaging.
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Affiliation(s)
- Ehsan Arbabi
- T. J. Watson Laboratory of Applied Physics and Kavli Nanoscience Institute , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125 , United States
| | - Jiaqi Li
- IMEC , Kapeldreef 75 , B-3001 Leuven , Belgium
- Department of Physics and Astronomy , KU Leuven , Celestijnenlaan 200 D , B-3001 Leuven , Belgium
| | - Romanus J Hutchins
- Department of Physics and Astronomy , University of Missouri Columbia , Columbia , Missouri 65211 , United States
| | - Seyedeh Mahsa Kamali
- T. J. Watson Laboratory of Applied Physics and Kavli Nanoscience Institute , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125 , United States
| | - Amir Arbabi
- Department of Electrical and Computer Engineering , University of Massachusetts Amherst , 151 Holdsworth Way , Amherst , Massachusetts 01003 , United States
| | - Yu Horie
- T. J. Watson Laboratory of Applied Physics and Kavli Nanoscience Institute , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125 , United States
| | - Pol Van Dorpe
- IMEC , Kapeldreef 75 , B-3001 Leuven , Belgium
- Department of Physics and Astronomy , KU Leuven , Celestijnenlaan 200 D , B-3001 Leuven , Belgium
| | - Viviana Gradinaru
- Division of Biology and Biological Engineering , California Institute of Technology , Pasadena , California 91125 , United States
| | - Daniel A Wagenaar
- Division of Biology and Biological Engineering , California Institute of Technology , Pasadena , California 91125 , United States
| | - Andrei Faraon
- T. J. Watson Laboratory of Applied Physics and Kavli Nanoscience Institute , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125 , United States
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40
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Wang S, Du H, Lin B, Liao C, Zhu X, Wang X, Chen H, Zhuo S, Jiang L, Li L, Tu H, Chen J. Spatial and temporal identification of cerebral infarctions based on multiphoton microscopic imaging. BIOMEDICAL OPTICS EXPRESS 2018; 9:2312-2325. [PMID: 29760990 PMCID: PMC5946791 DOI: 10.1364/boe.9.002312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/08/2018] [Accepted: 04/18/2018] [Indexed: 05/06/2023]
Abstract
Ischemic stroke is a leading cause of death and permanent disability worldwide. Middle cerebral artery occlusion (MCAO) of variable duration times could be anticipated to result in varying degrees of injury that evolve spatially over time. Therefore, investigations following strokes require information concerning the spatiotemporal dimensions of the ischemic core as well as of perilesional areas. In the present study, multiphoton microscopy (MPM) based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) was applied to image such pathophysiological events. The ischemic time-points for evaluation were set at 6, 24, 48, and 72 hours after MCAO. Our results demonstrated that MPM has the ability to not only identify the normal and ischemic brain regions, but also reveal morphological changes of the cortex and striatum at various times following permanent MCAO. These findings corresponded well with the hematoxylin and eosin (H&E) stained tissue images. With the technologic progression of miniaturized imaging devices, MPM can be developed into an effective diagnostic and monitoring tool for ischemic stroke.
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Affiliation(s)
- Shu Wang
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
- These authors contributed equally to this work
| | - Huiping Du
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
- These authors contributed equally to this work
| | - Bingbing Lin
- Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China
- These authors contributed equally to this work
| | - Chenxi Liao
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Xiaoqin Zhu
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Xingfu Wang
- Department of Pathology, The First Affiliated Hospital, Fujian Medical University, Fuzhou 350001, China
| | - Hong Chen
- Department of Pathology, The First Affiliated Hospital, Fujian Medical University, Fuzhou 350001, China
| | - Shuangmu Zhuo
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Liwei Jiang
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Lianhuang Li
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
| | - Haohua Tu
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jianxin Chen
- Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, Fujian Provincial Key Laboratory of Photonics Technology, Fujian Normal University, Fuzhou 350007, China
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41
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The brain during free movement - What can we learn from the animal model. Brain Res 2017; 1716:3-15. [PMID: 28893579 DOI: 10.1016/j.brainres.2017.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 08/11/2017] [Accepted: 09/04/2017] [Indexed: 11/21/2022]
Abstract
Animals, just like humans, can freely move. They do so for various important reasons, such as finding food and escaping predators. Observing these behaviors can inform us about the underlying cognitive processes. In addition, while humans can convey complicated information easily through speaking, animals need to move their bodies to communicate. This has prompted many creative solutions by animal neuroscientists to enable studying the brain during movement. In this review, we first summarize how animal researchers record from the brain while an animal is moving, by describing the most common neural recording techniques in animals and how they were adapted to record during movement. We further discuss the challenge of controlling or monitoring sensory input during free movement. However, not only is free movement a necessity to reflect the outcome of certain internal cognitive processes in animals, it is also a fascinating field of research since certain crucial behavioral patterns can only be observed and studied during free movement. Therefore, in a second part of the review, we focus on some key findings in animal research that specifically address the interaction between free movement and brain activity. First, focusing on walking as a fundamental form of free movement, we discuss how important such intentional movements are for understanding processes as diverse as spatial navigation, active sensing, and complex motor planning. Second, we propose the idea of regarding free movement as the expression of a behavioral state. This view can help to understand the general influence of movement on brain function. Together, the technological advancements towards recording from the brain during movement, and the scientific questions asked about the brain engaged in movement, make animal research highly valuable to research into the human "moving brain".
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42
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Qiu Z, Piyawattanamatha W. New Endoscopic Imaging Technology Based on MEMS Sensors and Actuators. MICROMACHINES 2017; 8:mi8070210. [PMID: 30400401 PMCID: PMC6190023 DOI: 10.3390/mi8070210] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 12/14/2022]
Abstract
Over the last decade, optical fiber-based forms of microscopy and endoscopy have extended the realm of applicability for many imaging modalities. Optical fiber-based imaging modalities permit the use of remote illumination sources and enable flexible forms supporting the creation of portable and hand-held imaging instrumentations to interrogate within hollow tissue cavities. A common challenge in the development of such devices is the design and integration of miniaturized optical and mechanical components. Until recently, microelectromechanical systems (MEMS) sensors and actuators have been playing a key role in shaping the miniaturization of these components. This is due to the precision mechanics of MEMS, microfabrication techniques, and optical functionality enabling a wide variety of movable and tunable mirrors, lenses, filters, and other optical structures. Many promising results from MEMS based optical fiber endoscopy have demonstrated great potentials for clinical translation. In this article, reviews of MEMS sensors and actuators for various fiber-optical endoscopy such as fluorescence, optical coherence tomography, confocal, photo-acoustic, and two-photon imaging modalities will be discussed. This advanced MEMS based optical fiber endoscopy can provide cellular and molecular features with deep tissue penetration enabling guided resections and early cancer assessment to better treatment outcomes.
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Affiliation(s)
- Zhen Qiu
- Department of Radiology, Stanford University, Stanford, CA 94305, USA.
| | - Wibool Piyawattanamatha
- Departments of Biomedical and Electronics Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
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43
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Bagramyan A, Galstian T, Saghatelyan A. Motion-free endoscopic system for brain imaging at variable focal depth using liquid crystal lenses. JOURNAL OF BIOPHOTONICS 2017; 10:762-774. [PMID: 26954754 DOI: 10.1002/jbio.201500261] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/18/2016] [Accepted: 02/14/2016] [Indexed: 06/05/2023]
Abstract
We present a motion-free system for microendoscopic imaging of biological tissues at variable focal depths. Fixed gradient index and electrically tunable liquid crystal lenses (TLCL) were used to build the imaging optical probe. The design of the TLCL enables polarization-independent and relatively low-voltage operation, significantly improving the energy efficiency of the system. A focal shift of approximately 74 ± 3 µm could be achieved by electrically controlling the TLCL using the driving frequency at a constant voltage. The potential of the system was tested by imaging neurons and spines in thick adult mouse brain sections and in vivo, in the adult mouse brain at different focal planes. Our results indicate that the developed system may enable depth-variable imaging of morpho-functional properties of neural circuitries in freely moving animals and can be used to investigate the functioning of these circuitries under normal and pathological conditions.
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Affiliation(s)
- Arutyun Bagramyan
- Centre for Optics, Photonics and Lasers, Department of Physics, Engineering Physics and Optics, University Laval, 2375 Rue de la Terrasse, Quebec City, QC, Canada, G1V 0A6
- Quebec Mental Health Institute, 2601 chemin de la Canardière, Quebec City, QC, Canada, G1J 2G3
| | - Tigran Galstian
- Centre for Optics, Photonics and Lasers, Department of Physics, Engineering Physics and Optics, University Laval, 2375 Rue de la Terrasse, Quebec City, QC, Canada, G1V 0A6
| | - Armen Saghatelyan
- Quebec Mental Health Institute, 2601 chemin de la Canardière, Quebec City, QC, Canada, G1J 2G3
- Department of Psychiatry and Neuroscience, Faculty of Medicine, University Laval, 1050 avenue de la Médecine, Quebec City, QC, Canada, G1V 0A6
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44
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Fast high-resolution miniature two-photon microscopy for brain imaging in freely behaving mice. Nat Methods 2017; 14:713-719. [PMID: 28553965 DOI: 10.1038/nmeth.4305] [Citation(s) in RCA: 254] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 04/21/2017] [Indexed: 12/17/2022]
Abstract
Developments in miniaturized microscopes have enabled visualization of brain activities and structural dynamics in animals engaging in self-determined behaviors. However, it remains a challenge to resolve activity at single dendritic spines in freely behaving animals. Here, we report the design and application of a fast high-resolution, miniaturized two-photon microscope (FHIRM-TPM) that accomplishes this goal. With a headpiece weighing 2.15 g and a hollow-core photonic crystal fiber delivering 920-nm femtosecond laser pulses, the FHIRM-TPM is capable of imaging commonly used biosensors (GFP and GCaMP6) at high spatiotemporal resolution (0.64 μm laterally and 3.35 μm axially, 40 Hz at 256 × 256 pixels for raster scanning and 10,000 Hz for free-line scanning). We demonstrate the microscope's robustness with hour-long recordings of neuronal activities at the level of spines in mice experiencing vigorous body movements.
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45
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Duan X, Li H, Li X, Oldham KR, Wang TD. Axial beam scanning in multiphoton microscopy with MEMS-based actuator. OPTICS EXPRESS 2017; 25:2195-2205. [PMID: 29519067 PMCID: PMC5772401 DOI: 10.1364/oe.25.002195] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We demonstrate a remotely located microelectromechanical systems (MEMS) actuator that can translate >400 μm to perform axial beam scanning in a multiphoton microscope. We use a 2-dimensional MEMS mirror for lateral scanning, and collected multiphoton excited fluorescence images in either the horizontal or vertical plane with a field-of-view of either 270 × 270 or 270 × 200 μm2, respectively, at 5 frames per second. Axial resolution varied from 4.5 to 7 μm over the scan range. The compact size of the actuator and scanner allows for use in an endomicroscope to collect images in the vertical plane with >200 μm depth.
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Affiliation(s)
- Xiyu Duan
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Haijun Li
- Dept. of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Xue Li
- Dept. of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Kenn R. Oldham
- Dept. of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Thomas D. Wang
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Dept. of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
- Dept. of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
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46
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Liang W, Hall G, Messerschmidt B, Li MJ, Li X. Nonlinear optical endomicroscopy for label-free functional histology in vivo. LIGHT, SCIENCE & APPLICATIONS 2017; 6:e17082-. [PMID: 29854567 PMCID: PMC5972527 DOI: 10.1038/lsa.2017.82] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 05/06/2017] [Accepted: 05/07/2017] [Indexed: 05/19/2023]
Abstract
This manuscript reports on the first two-photon, label-free, metabolic imaging of biological tissues in vivo at histological resolution on an extremely compact, fiber-optic endomicroscopy platform. This system provides new opportunities for performing non-invasive and functional histological imaging of internal organs in vivo, in situ and in real time. As a routine clinical procedure, traditional histology has made significant impacts on medicine. However, the procedure is invasive and time consuming, suffers random sampling errors, and cannot provide in vivo functional information. The technology reported here features an extremely compact and flexible fiber-optic probe ~2 mm in diameter, enabling direct access to internal organs. Unprecedented two-photon imaging quality comparable to a large bench-top laser scanning microscope was achieved through technological innovations in double-clad fiber optics and miniature objective lenses (among many others). In addition to real-time label-free visualization of biological tissues in situ with subcellular histological detail, we demonstrated for the first time in vivo two-photon endomicroscopic metabolic imaging on a functioning mouse kidney model. Such breakthroughs in nonlinear endoscopic imaging capability present numerous promising opportunities for paradigm-shifting applications in both clinical diagnosis and basic research.
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Affiliation(s)
- Wenxuan Liang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Gunnsteinn Hall
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | | | - Ming-Jun Li
- Science and Technology Division, Corning Incorporated, Corning, NY 14831, USA
| | - Xingde Li
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
- E-mail:
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Sigal I, Koletar MM, Ringuette D, Gad R, Jeffrey M, Carlen PL, Stefanovic B, Levi O. Imaging brain activity during seizures in freely behaving rats using a miniature multi-modal imaging system. BIOMEDICAL OPTICS EXPRESS 2016; 7:3596-3609. [PMID: 27699123 PMCID: PMC5030035 DOI: 10.1364/boe.7.003596] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/11/2016] [Accepted: 08/11/2016] [Indexed: 05/20/2023]
Abstract
We report on a miniature label-free imaging system for monitoring brain blood flow and blood oxygenation changes in awake, freely behaving rats. The device, weighing 15 grams, enables imaging in a ∼ 2 × 2 mm field of view with 4.4 μm lateral resolution and 1 - 8 Hz temporal sampling rate. The imaging is performed through a chronically-implanted cranial window that remains optically clear between 2 to > 6 weeks after the craniotomy. This imaging method is well suited for longitudinal studies of chronic models of brain diseases and disorders. In this work, it is applied to monitoring neurovascular coupling during drug-induced absence-like seizures 6 weeks following the craniotomy.
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Affiliation(s)
- Iliya Sigal
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9,
Canada
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, 10 King’s College Road, Toronto, ON M5S 3G4,
Canada
| | - Margaret M. Koletar
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5,
Canada
| | - Dene Ringuette
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9,
Canada
| | - Raanan Gad
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9,
Canada
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, 10 King’s College Road, Toronto, ON M5S 3G4,
Canada
| | - Melanie Jeffrey
- Krembil Research Institute, 60 Leonard Avenue, Toronto, ON M5T 2S1,
Canada
| | - Peter L. Carlen
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9,
Canada
- Krembil Research Institute, 60 Leonard Avenue, Toronto, ON M5T 2S1,
Canada
| | - Bojana Stefanovic
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5,
Canada
- Department of Medical Biophysics, University of Toronto, 2075 Bayview Avenue, Toronto, ON M4N 3M5,
Canada
| | - Ofer Levi
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9,
Canada
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, 10 King’s College Road, Toronto, ON M5S 3G4,
Canada
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48
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Wang Y, Li Z, Liang X, Fu L. Four-plate piezoelectric actuator driving a large-diameter special optical fiber for nonlinear optical microendoscopy. OPTICS EXPRESS 2016; 24:19949-19960. [PMID: 27557270 DOI: 10.1364/oe.24.019949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In nonlinear optical microendoscope (NOME), a fiber with excellent optical characteristics and a miniature scanning mechanism at the distal end are two key components. Double-clad fibers (DCFs) and double-clad photonic crystal fibers (DCPCFs) have shown great optical characteristics but limited vibration amplitude due to large diameter. Besides reducing the damping of fiber cantilever, optimizing the structural of the actuator for lower energy dissipation also contributes to better driving capability. This paper presented an optimized actuator for driving a particular fiber cantilever in the view point of energy. Firstly, deformation energy of a bending fiber cantilever operating in resonant mode is investigated. Secondly, strain and stress analyses revealed that the four-plate actuator achieved lower energy dissipation. Then, finite-element simulations showed that the large-diameter fiber yielded an adequate vibration amplitude driven by a four-plate actuator, which was confirmed by experiments of our home-made four-plate actuator prototypes. Additionally, a NOME based on a DCPCF with a diameter of 350 μm driven by four-plate piezoelectric actuator has been developed. The NOME can excite and collect intrinsic second-harmonic and two-photon fluorescence signals with the excitation power of 10-30 mW and an adequate field of view of 200 μm, which suggest great potential applications in neuroscience and clinical diagnoses.
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49
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Huang L, Merson TD, Bourne JA. In vivo whole brain, cellular and molecular imaging in nonhuman primate models of neuropathology. Neurosci Biobehav Rev 2016; 66:104-18. [PMID: 27151822 DOI: 10.1016/j.neubiorev.2016.04.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 03/31/2016] [Accepted: 04/13/2016] [Indexed: 12/22/2022]
Abstract
Rodents have been the principal model to study brain anatomy and function due to their well-mapped brain architecture, rapid reproduction and amenability to genetic modification. However, there are clear limitations, for example their simpler neocortex, necessitating the need to adopt a model that is closer to humans in order to understand human cognition and brain conditions. Nonhuman primates (NHPs) are ideally suited as they are our closest relatives in the animal kingdom but in vivo imaging technologies to study brain structure and function in these species can be challenging. With the surge in NHP research in recent years, scientists have begun adapting imaging technologies, such as two-photon microscopy, for these species. Here we review the various NHP models that exist as well as their use in advanced microscopic and mesoscopic studies. We discuss the challenges in the field and investigate the opportunities that lie ahead.
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Affiliation(s)
- Lieven Huang
- Australian Regenerative Medicine Institute, Monash University, 15 Innovation Walk, Clayton, Victoria 3800, Australia
| | - Tobias D Merson
- The Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - James A Bourne
- Australian Regenerative Medicine Institute, Monash University, 15 Innovation Walk, Clayton, Victoria 3800, Australia.
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50
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Wang J, Yang M, Yang L, Zhang Y, Yuan J, Liu Q, Hou X, Fu L. A Confocal Endoscope for Cellular Imaging. ENGINEERING 2015; 1:351-360. [DOI: 10.15302/j-eng-2015081] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/11/2023]
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