1
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Hara Y, Ichiraku A, Matsuda T, Sakane A, Sasaki T, Nagai T, Horikawa K. High-affinity tuning of single fluorescent protein-type indicators by flexible linker length optimization in topology mutant. Commun Biol 2024; 7:705. [PMID: 38851844 PMCID: PMC11162441 DOI: 10.1038/s42003-024-06394-0] [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: 05/17/2023] [Accepted: 05/29/2024] [Indexed: 06/10/2024] Open
Abstract
Genetically encoded Ca2+ indicators (GECIs) are versatile for live imaging of cellular activities. Besides the brightness and dynamic range of signal change of GECIs, Ca2+ affinity is another critical parameter for successful Ca2+ imaging, as the concentration range of Ca2+ dynamics differs from low nanomolar to sub-millimolar depending on the celltype and organism. However, ultrahigh-affinity GECIs, particularly the single fluorescent protein (1FP)-type, are lacking. Here, we report a simple strategy that increases Ca2+ affinity through the linker length optimization in topology mutants of existing 1FP-type GECIs. The resulting ultrahigh-affinity GECIs, CaMPARI-nano, BGECO-nano, and RCaMP-nano (Kd = 17-25 nM), enable unique biological applications, including the detection of low nanomolar Ca2+ dynamics, highlighting active signaling cells, and multi-functional imaging with other second messengers. The linker length optimization in topology mutants could be applied to other 1FP-type indicators of glutamate and potassium, rendering it a widely applicable technique for modulating indicator affinity.
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Affiliation(s)
- Yusuke Hara
- Department of Optical Imaging, Advanced Research Promotion Center, Tokushima University, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan
| | - Aya Ichiraku
- Department of Optical Imaging, Advanced Research Promotion Center, Tokushima University, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan
| | - Tomoki Matsuda
- Department of Biomolecular Science and Engineering, SANKEN, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan
| | - Ayuko Sakane
- Department of Biochemistry, Tokushima University Graduate School of Medicine, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan
- Division of Interdisciplinary Researches for Medicine and Photonics, Institute of Post-LED Photonics (pLED), Tokushima University, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan
| | - Takuya Sasaki
- Department of Biochemistry, Tokushima University Graduate School of Medicine, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan
| | - Takeharu Nagai
- Department of Biomolecular Science and Engineering, SANKEN, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan
- Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan
| | - Kazuki Horikawa
- Department of Optical Imaging, Advanced Research Promotion Center, Tokushima University, 3-18-15 Kuramoto, Tokushima, Tokushima, 770-8503, Japan.
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2
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Barroso M, Monaghan MG, Niesner R, Dmitriev RI. Probing organoid metabolism using fluorescence lifetime imaging microscopy (FLIM): The next frontier of drug discovery and disease understanding. Adv Drug Deliv Rev 2023; 201:115081. [PMID: 37647987 PMCID: PMC10543546 DOI: 10.1016/j.addr.2023.115081] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/20/2023] [Accepted: 08/24/2023] [Indexed: 09/01/2023]
Abstract
Organoid models have been used to address important questions in developmental and cancer biology, tissue repair, advanced modelling of disease and therapies, among other bioengineering applications. Such 3D microenvironmental models can investigate the regulation of cell metabolism, and provide key insights into the mechanisms at the basis of cell growth, differentiation, communication, interactions with the environment and cell death. Their accessibility and complexity, based on 3D spatial and temporal heterogeneity, make organoids suitable for the application of novel, dynamic imaging microscopy methods, such as fluorescence lifetime imaging microscopy (FLIM) and related decay time-assessing readouts. Several biomarkers and assays have been proposed to study cell metabolism by FLIM in various organoid models. Herein, we present an expert-opinion discussion on the principles of FLIM and PLIM, instrumentation and data collection and analysis protocols, and general and emerging biosensor-based approaches, to highlight the pioneering work being performed in this field.
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Affiliation(s)
- Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208, USA
| | - Michael G Monaghan
- Department of Mechanical, Manufacturing and Biomedical Engineering, Trinity College Dublin, Dublin 02, Ireland
| | - Raluca Niesner
- Dynamic and Functional In Vivo Imaging, Freie Universität Berlin and Biophysical Analytics, German Rheumatism Research Center, Berlin, Germany
| | - Ruslan I Dmitriev
- Tissue Engineering and Biomaterials Group, Department of Human Structure and Repair, Faculty of Medicine and Health Sciences, Ghent University, C. Heymanslaan 10, 9000 Ghent, Belgium; Ghent Light Microscopy Core, Ghent University, 9000 Ghent, Belgium.
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3
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Morita M. Modern Microscopic Approaches to Astrocytes. Int J Mol Sci 2023; 24:ijms24065883. [PMID: 36982958 PMCID: PMC10051528 DOI: 10.3390/ijms24065883] [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: 12/31/2022] [Revised: 03/08/2023] [Accepted: 03/14/2023] [Indexed: 03/30/2023] Open
Abstract
Microscopy started as the histological analysis based on intrinsic optical properties of tissues such as the refractive index and light absorption, and is expanding to include the visualization of organelles by chemical staining, localization of molecules by immunostaining, physiological measurements such as Ca2+ imaging, functional manipulation by optogenetics, and comprehensive analysis of chemical composition by Raman spectra. The microscope is one of the most important tools in neuroscience, which aims to reveal the complex intercellular communications underlying brain function and pathology. Many aspects of astrocytes, including the structures of their fine processes and physiological activities in concert with neurons and blood vessels, were revealed in the course of innovations in modern microscopy. The evolution of modern microscopy is a consequence of breakthroughs in spatiotemporal resolutions and expansions in molecular and physiological targets due to the progress in optics and information technology, as well as the inventions of probes using organic chemistry and molecular biology. This review overviews the modern microscopic approach to astrocytes.
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Affiliation(s)
- Mitsuhiro Morita
- Department of Biology, Graduate School of Sciences, Kobe University, Kobe 657-8501, Japan
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4
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Wang Q, Li Y, Xiao D, Zang Z, Jiao Z, Chen Y, Li DDU. Simple and Robust Deep Learning Approach for Fast Fluorescence Lifetime Imaging. SENSORS (BASEL, SWITZERLAND) 2022; 22:7293. [PMID: 36236390 PMCID: PMC9572653 DOI: 10.3390/s22197293] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/17/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
Fluorescence lifetime imaging (FLIM) is a powerful tool that provides unique quantitative information for biomedical research. In this study, we propose a multi-layer-perceptron-based mixer (MLP-Mixer) deep learning (DL) algorithm named FLIM-MLP-Mixer for fast and robust FLIM analysis. The FLIM-MLP-Mixer has a simple network architecture yet a powerful learning ability from data. Compared with the traditional fitting and previously reported DL methods, the FLIM-MLP-Mixer shows superior performance in terms of accuracy and calculation speed, which has been validated using both synthetic and experimental data. All results indicate that our proposed method is well suited for accurately estimating lifetime parameters from measured fluorescence histograms, and it has great potential in various real-time FLIM applications.
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Affiliation(s)
- Quan Wang
- Department of Biomedical Engineering, University of Strathclyde, Glasgow G4 0RU, UK
| | - Yahui Li
- Key Laboratory of Ultra-Fast Photoelectric Diagnostics Technology, Xi’an Institute of Optics and Precision Mechanics, Xi’an 710049, China
| | - Dong Xiao
- Department of Biomedical Engineering, University of Strathclyde, Glasgow G4 0RU, UK
| | - Zhenya Zang
- Department of Biomedical Engineering, University of Strathclyde, Glasgow G4 0RU, UK
| | - Zi’ao Jiao
- Department of Biomedical Engineering, University of Strathclyde, Glasgow G4 0RU, UK
| | - Yu Chen
- Department of Physics, University of Strathclyde, Glasgow G4 0NG, UK
| | - David Day Uei Li
- Department of Biomedical Engineering, University of Strathclyde, Glasgow G4 0RU, UK
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5
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Masia F, Dewitte W, Borri P, Langbein W. uFLIM - Unsupervised analysis of FLIM-FRET microscopy data. Med Image Anal 2022; 82:102579. [PMID: 36049452 DOI: 10.1016/j.media.2022.102579] [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: 12/08/2021] [Revised: 05/24/2022] [Accepted: 08/11/2022] [Indexed: 11/16/2022]
Abstract
Despite their widespread use in cell biology, fluorescence lifetime imaging microscopy (FLIM) data-sets are challenging to analyse, because each spatial position can contain a superposition of multiple fluorescent components. Here, we present a data analysis method employing all information in the available photon budget, as well as being fast. The method, called uFLIM, determines spatial distributions and temporal dynamics of multiple fluorescent components with no prior knowledge. It goes significantly beyond current approaches which either assume the functional dependence of the dynamics, e.g. an exponential decay, or require dynamics to be known, or calibrated. Its efficient non-negative matrix factorization algorithm allows for real-time data processing. We validate in silico that uFLIM is capable to disentangle the spatial distribution and spectral properties of five fluorescing probes, from only two excitation and detection channels and a photon budget of 100 detected photons per pixel. By adapting the method to data exhibiting Förster resonant energy transfer (FRET), we retrieve the spatial and transfer rate distribution of the bound species, without constrains on donor and acceptor dynamics.
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Affiliation(s)
- Francesco Masia
- School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA, UK; School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
| | - Walter Dewitte
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
| | - Paola Borri
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
| | - Wolfgang Langbein
- School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA, UK.
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6
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Quarato G, Llambi F, Guy CS, Min J, Actis M, Sun H, Narina S, Pruett-Miller SM, Peng J, Rankovic Z, Green DR. Ca 2+-mediated mitochondrial inner membrane permeabilization induces cell death independently of Bax and Bak. Cell Death Differ 2022; 29:1318-1334. [PMID: 35726022 DOI: 10.1038/s41418-022-01025-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 05/27/2022] [Accepted: 06/03/2022] [Indexed: 12/15/2022] Open
Abstract
The ability of mitochondria to buffer a rapid rise in cytosolic Ca2+ is a hallmark of proper cell homeostasis. Here, we employed m-3M3FBS, a putative phospholipase C (PLC) agonist, to explore the relationships between intracellular Ca2+ imbalance, mitochondrial physiology, and cell death. m-3M3FBS induced a potent dose-dependent Ca2+ release from the endoplasmic reticulum (ER), followed by a rise in intra-mitochondrial Ca2+. When the latter exceeded the organelle buffering capacity, an abrupt mitochondrial inner membrane permeabilization (MIMP) occurred, releasing matrix contents into the cytosol. MIMP was followed by cell death that was independent of Bcl-2 family members and inhibitable by the intracellular Ca2+ chelator BAPTA-AM. Cyclosporin A (CsA), capable of blocking the mitochondrial permeability transition (MPT), completely prevented cell death induced by m-3M3FBS. However, CsA acted upstream of mitochondria by preventing Ca2+ release from ER stores. Therefore, loss of Ca2+ intracellular balance and mitochondrial Ca2+ overload followed by MIMP induced a cell death process that is distinct from Bcl-2 family-regulated mitochondrial outer membrane permeabilization (MOMP). Further, the inhibition of cell death by CsA or its analogues can be independent of effects on the MPT.
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Affiliation(s)
- Giovanni Quarato
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
| | - Fabien Llambi
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.,Relay Therapeutics, Cambridge, MA, 02139, USA
| | - Cliff S Guy
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Jaeki Min
- Department of Chemical Biology & Therapeutic, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.,Amgen Inc., Thousand Oaks, CA, 91320, USA
| | - Marisa Actis
- Department of Chemical Biology & Therapeutic, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Huan Sun
- Department of Structural Biology, Department of Developmental Neurobiology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Shilpa Narina
- Department of Cell and Molecular Biology and The Center for Advanced Genome Engineering, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Shondra M Pruett-Miller
- Department of Cell and Molecular Biology and The Center for Advanced Genome Engineering, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Junmin Peng
- Department of Structural Biology, Department of Developmental Neurobiology, Center for Proteomics and Metabolomics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Zoran Rankovic
- Department of Chemical Biology & Therapeutic, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Douglas R Green
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
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7
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Hilzenrat G, Gill ET, McArthur SL. Imaging approaches for monitoring three-dimensional cell and tissue culture systems. JOURNAL OF BIOPHOTONICS 2022; 15:e202100380. [PMID: 35357086 DOI: 10.1002/jbio.202100380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 03/27/2022] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
The past decade has seen an increasing demand for more complex, reproducible and physiologically relevant tissue cultures that can mimic the structural and biological features of living tissues. Monitoring the viability, development and responses of such tissues in real-time are challenging due to the complexities of cell culture physical characteristics and the environments in which these cultures need to be maintained in. Significant developments in optics, such as optical manipulation, improved detection and data analysis, have made optical imaging a preferred choice for many three-dimensional (3D) cell culture monitoring applications. The aim of this review is to discuss the challenges associated with imaging and monitoring 3D tissues and cell culture, and highlight topical label-free imaging tools that enable bioengineers and biophysicists to non-invasively characterise engineered living tissues.
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Affiliation(s)
- Geva Hilzenrat
- Bioengineering Engineering Group, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, Victoria, Australia
| | - Emma T Gill
- Bioengineering Engineering Group, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, Victoria, Australia
| | - Sally L McArthur
- Bioengineering Engineering Group, School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Biomedical Manufacturing, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, Victoria, Australia
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8
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Héliot L, Leray A. Simple phasor-based deep neural network for fluorescence lifetime imaging microscopy. Sci Rep 2021; 11:23858. [PMID: 34903737 PMCID: PMC8668934 DOI: 10.1038/s41598-021-03060-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 11/23/2021] [Indexed: 12/29/2022] Open
Abstract
Fluorescence lifetime imaging microscopy (FLIM) is a powerful technique to probe the molecular environment of fluorophores. The analysis of FLIM images is usually performed with time consuming fitting methods. For accelerating this analysis, sophisticated deep learning architectures based on convolutional neural networks have been developed for restrained lifetime ranges but they require long training time. In this work, we present a simple neural network formed only with fully connected layers able to analyze fluorescence lifetime images. It is based on the reduction of high dimensional fluorescence intensity temporal decays into four parameters which are the phasor coordinates, the mean and amplitude-weighted lifetimes. This network called Phasor-Net has been applied for a time domain FLIM system excited with an 80 MHz laser repetition frequency, with negligible jitter and afterpulsing. Due to the restricted time interval of 12.5 ns, the training range of the lifetimes was limited between 0.2 and 3.0 ns; and the total photon number was lower than 106, as encountered in live cell imaging. From simulated biexponential decays, we demonstrate that Phasor-Net is more precise and less biased than standard fitting methods. We demonstrate also that this simple architecture gives almost comparable performance than those obtained from more sophisticated networks but with a faster training process (15 min instead of 30 min). We finally apply successfully our method to determine biexponential decays parameters for FLIM experiments in living cells expressing EGFP linked to mCherry and fused to a plasma membrane protein.
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Affiliation(s)
- Laurent Héliot
- PhLAM Laboratoire de Physique Des Lasers, Atomes Et Molécules, UMR 8523, CNRS, University of Lille, Lille, France.
| | - Aymeric Leray
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303, CNRS, Université de Bourgogne Franche-Comté, Dijon, France.
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9
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van der Linden FH, Mahlandt EK, Arts JJG, Beumer J, Puschhof J, de Man SMA, Chertkova AO, Ponsioen B, Clevers H, van Buul JD, Postma M, Gadella TWJ, Goedhart J. A turquoise fluorescence lifetime-based biosensor for quantitative imaging of intracellular calcium. Nat Commun 2021; 12:7159. [PMID: 34887382 PMCID: PMC8660884 DOI: 10.1038/s41467-021-27249-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 11/10/2021] [Indexed: 11/08/2022] Open
Abstract
The most successful genetically encoded calcium indicators (GECIs) employ an intensity or ratiometric readout. Despite a large calcium-dependent change in fluorescence intensity, the quantification of calcium concentrations with GECIs is problematic, which is further complicated by the sensitivity of all GECIs to changes in the pH in the biological range. Here, we report on a sensing strategy in which a conformational change directly modifies the fluorescence quantum yield and fluorescence lifetime of a circular permutated turquoise fluorescent protein. The fluorescence lifetime is an absolute parameter that enables straightforward quantification, eliminating intensity-related artifacts. An engineering strategy that optimizes lifetime contrast led to a biosensor that shows a 3-fold change in the calcium-dependent quantum yield and a fluorescence lifetime change of 1.3 ns. We dub the biosensor Turquoise Calcium Fluorescence LIfeTime Sensor (Tq-Ca-FLITS). The response of the calcium sensor is insensitive to pH between 6.2-9. As a result, Tq-Ca-FLITS enables robust measurements of intracellular calcium concentrations by fluorescence lifetime imaging. We demonstrate quantitative imaging of calcium concentrations with the turquoise GECI in single endothelial cells and human-derived organoids.
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Affiliation(s)
- Franka H van der Linden
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Eike K Mahlandt
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Janine J G Arts
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
- Department of Molecular Hematology at Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Joep Beumer
- Oncode Institute, Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center, Utrecht, The Netherlands
| | - Jens Puschhof
- Oncode Institute, Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center, Utrecht, The Netherlands
| | - Saskia M A de Man
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Anna O Chertkova
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Bas Ponsioen
- Center for Molecular Medicine, Oncode Institute, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Hans Clevers
- Oncode Institute, Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center, Utrecht, The Netherlands
| | - Jaap D van Buul
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
- Department of Molecular Hematology at Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Marten Postma
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Theodorus W J Gadella
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Joachim Goedhart
- Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.
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10
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Chang YT, Van Sieleghem E, Lee J, Van Dorpe P, Van Hoof C. Performance and limitation estimation of a three-tap gated imaging sensor in wide field time-gated fluorescence lifetime imaging systems. APPLIED OPTICS 2021; 60:7446-7454. [PMID: 34613034 DOI: 10.1364/ao.428590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
In this paper, a computational performance analysis is presented of a wide-field time-gated fluorescence lifetime imaging microscope (FLIM) using practically realizable properties of the laser, sample, and a three-tap time-gated CMOS image sensor. The impact of these component-level properties on the accuracy and the precision of the measurement results are estimated and discussed based on Monte Carlo simulations. The correlation between the detector speed and the accuracy of the extracted fluorescence lifetime is studied, and the minimum required incident photoelectron number of each pixel is estimated for different detector speeds and different fluorescence lifetime measurements. In addition, the detection limits due to the dark current and the parasitic light sensitivity of the detector are also investigated. This work gives an overview of the required fluorescence emission condition as well as the required detector properties for a three-tap time-gated image sensor to achieve good FLIM data in biological applications.
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11
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Semyanov A, Henneberger C, Agarwal A. Making sense of astrocytic calcium signals — from acquisition to interpretation. Nat Rev Neurosci 2020; 21:551-564. [DOI: 10.1038/s41583-020-0361-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2020] [Indexed: 12/31/2022]
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12
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Karpf S, Riche CT, Di Carlo D, Goel A, Zeiger WA, Suresh A, Portera-Cailliau C, Jalali B. Spectro-temporal encoded multiphoton microscopy and fluorescence lifetime imaging at kilohertz frame-rates. Nat Commun 2020; 11:2062. [PMID: 32346060 PMCID: PMC7188897 DOI: 10.1038/s41467-020-15618-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 03/18/2020] [Indexed: 12/21/2022] Open
Abstract
Two-Photon Microscopy has become an invaluable tool for biological and medical research, providing high sensitivity, molecular specificity, inherent three-dimensional sub-cellular resolution and deep tissue penetration. In terms of imaging speeds, however, mechanical scanners still limit the acquisition rates to typically 10-100 frames per second. Here we present a high-speed non-linear microscope achieving kilohertz frame rates by employing pulse-modulated, rapidly wavelength-swept lasers and inertia-free beam steering through angular dispersion. In combination with a high bandwidth, single-photon sensitive detector, this enables recording of fluorescent lifetimes at speeds of 88 million pixels per second. We show high resolution, multi-modal - two-photon fluorescence and fluorescence lifetime (FLIM) - microscopy and imaging flow cytometry with a digitally reconfigurable laser, imaging system and data acquisition system. These high speeds should enable high-speed and high-throughput image-assisted cell sorting.
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Affiliation(s)
- Sebastian Karpf
- Department of Electrical Engineering and Computational Science, University of California, Los Angeles (UCLA), Los Angeles, CA-90095, USA.
- Institute of Biomedical Optics (BMO), University of Luebeck, 23562, Luebeck, Germany.
| | - Carson T Riche
- Department of Bioengineering, University of California, Los Angeles (UCLA), Los Angeles, CA-90095, USA
| | - Dino Di Carlo
- Department of Bioengineering, University of California, Los Angeles (UCLA), Los Angeles, CA-90095, USA
| | - Anubhuti Goel
- Department of Neurology, University of California, Los Angeles (UCLA), Los Angeles, CA-90095, USA
| | - William A Zeiger
- Department of Neurology, University of California, Los Angeles (UCLA), Los Angeles, CA-90095, USA
| | - Anand Suresh
- Department of Neurology, University of California, Los Angeles (UCLA), Los Angeles, CA-90095, USA
| | - Carlos Portera-Cailliau
- Department of Neurology, University of California, Los Angeles (UCLA), Los Angeles, CA-90095, USA
| | - Bahram Jalali
- Department of Electrical Engineering and Computational Science, University of California, Los Angeles (UCLA), Los Angeles, CA-90095, USA
- Department of Bioengineering, University of California, Los Angeles (UCLA), Los Angeles, CA-90095, USA
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13
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Levitt JA, Poland SP, Krstajic N, Pfisterer K, Erdogan A, Barber PR, Parsons M, Henderson RK, Ameer-Beg SM. Quantitative real-time imaging of intracellular FRET biosensor dynamics using rapid multi-beam confocal FLIM. Sci Rep 2020; 10:5146. [PMID: 32198437 PMCID: PMC7083966 DOI: 10.1038/s41598-020-61478-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/14/2020] [Indexed: 01/21/2023] Open
Abstract
Fluorescence lifetime imaging (FLIM) is a quantitative, intensity-independent microscopical method for measurement of diverse biochemical and physical properties in cell biology. It is a highly effective method for measurements of Förster resonance energy transfer (FRET), and for quantification of protein-protein interactions in cells. Time-domain FLIM-FRET measurements of these dynamic interactions are particularly challenging, since the technique requires excellent photon statistics to derive experimental parameters from the complex decay kinetics often observed from fluorophores in living cells. Here we present a new time-domain multi-confocal FLIM instrument with an array of 64 visible beamlets to achieve parallelised excitation and detection with average excitation powers of ~ 1–2 μW per beamlet. We exemplify this instrument with up to 0.5 frames per second time-lapse FLIM measurements of cAMP levels using an Epac-based fluorescent biosensor in live HeLa cells with nanometer spatial and picosecond temporal resolution. We demonstrate the use of time-dependent phasor plots to determine parameterisation for multi-exponential decay fitting to monitor the fractional contribution of the activated conformation of the biosensor. Our parallelised confocal approach avoids having to compromise on speed, noise, accuracy in lifetime measurements and provides powerful means to quantify biochemical dynamics in living cells.
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Affiliation(s)
- James A Levitt
- Microscopy Innovation Centre, Guy's Campus, Kings College, London, SE1 1UL, UK.,Richard Dimbleby Laboratories, School of Cancer and Pharmaceutical Sciences, Guy's Campus, Kings College London, London, SE1 1UL, UK
| | - Simon P Poland
- Richard Dimbleby Laboratories, School of Cancer and Pharmaceutical Sciences, Guy's Campus, Kings College London, London, SE1 1UL, UK
| | - Nikola Krstajic
- Institute for Microelectronics and Nanosystems, School of Engineering, College of Science and Engineering, University of Edinburgh, Edinburgh, EH9 3FB, UK
| | - Karin Pfisterer
- Randall Centre for Cell and Molecular Biophysics, Guy's Campus, Kings College, London, SE1 1UL, UK
| | - Ahmet Erdogan
- Institute for Microelectronics and Nanosystems, School of Engineering, College of Science and Engineering, University of Edinburgh, Edinburgh, EH9 3FB, UK
| | - Paul R Barber
- UCL Cancer Institute, Paul O'Gorman Building, University College London, London, WC1E 6DD, UK
| | - Maddy Parsons
- Randall Centre for Cell and Molecular Biophysics, Guy's Campus, Kings College, London, SE1 1UL, UK
| | - Robert K Henderson
- Institute for Microelectronics and Nanosystems, School of Engineering, College of Science and Engineering, University of Edinburgh, Edinburgh, EH9 3FB, UK
| | - Simon M Ameer-Beg
- Richard Dimbleby Laboratories, School of Cancer and Pharmaceutical Sciences, Guy's Campus, Kings College London, London, SE1 1UL, UK.
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14
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Zhu S, Xu Y, Li D. Three-observation-window time-gated algorithm for fluorescence lifetime detection. APPLIED OPTICS 2020; 59:2739-2745. [PMID: 32225823 DOI: 10.1364/ao.384342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/18/2020] [Indexed: 06/10/2023]
Abstract
A novel three-observation-window time-gated algorithm that combines overlapped windows and discrete windows together is developed for accurate fluorescence lifetime extraction. The new algorithm adopting a rapid lifetime determination strategy can offer an excellent ability to precisely detect long fluorescence lifetime for fluorescence lifetime imaging microscopy. Monte Carlo simulation indicates that an extremely small relative standard deviation below 0.4% is obtained over a wide fluorescence lifetime range from 5 ns to 30 ns. The detection error of the short fluorescence lifetime less than 5 ns is further reduced by means of an adaptive window width method. In contrast to other algorithms, such as time-correlated single-photon counting and traditional gated-window methods, not only the detection range but also the measurement accuracy is dramatically enhanced.
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15
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King CM, Bohmbach K, Minge D, Delekate A, Zheng K, Reynolds J, Rakers C, Zeug A, Petzold GC, Rusakov DA, Henneberger C. Local Resting Ca 2+ Controls the Scale of Astroglial Ca 2+ Signals. Cell Rep 2020; 30:3466-3477.e4. [PMID: 32160550 PMCID: PMC7068654 DOI: 10.1016/j.celrep.2020.02.043] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 12/21/2019] [Accepted: 02/06/2020] [Indexed: 02/07/2023] Open
Abstract
Astroglia regulate neurovascular coupling while engaging in signal exchange with neurons. The underlying cellular machinery is thought to rely on astrocytic Ca2+ signals, but what controls their amplitude and waveform is poorly understood. Here, we employ time-resolved two-photon excitation fluorescence imaging in acute hippocampal slices and in cortex in vivo to find that resting [Ca2+] predicts the scale (amplitude) and the maximum (peak) of astroglial Ca2+ elevations. We bidirectionally manipulate resting [Ca2+] by uncaging intracellular Ca2+ or Ca2+ buffers and use ratiometric imaging of a genetically encoded Ca2+ indicator to establish that alterations in resting [Ca2+] change co-directionally the peak level and anti-directionally the amplitude of local Ca2+ transients. This relationship holds for spontaneous and for induced (for instance by locomotion) Ca2+ signals. Our findings uncover a basic generic rule of Ca2+ signal formation in astrocytes, thus also associating the resting Ca2+ level with the physiological "excitability" state of astroglia.
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Affiliation(s)
- Claire M King
- Institute of Neurology, University College London, London, UK
| | - Kirsten Bohmbach
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Daniel Minge
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Andrea Delekate
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Kaiyu Zheng
- Institute of Neurology, University College London, London, UK
| | - James Reynolds
- Institute of Neurology, University College London, London, UK
| | - Cordula Rakers
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Andre Zeug
- Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany; Department of Neurology, University Hospital Bonn, Bonn, Germany
| | | | - Christian Henneberger
- Institute of Neurology, University College London, London, UK; Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany; German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
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16
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Poudel C, Mela I, Kaminski CF. High-throughput, multi-parametric, and correlative fluorescence lifetime imaging. Methods Appl Fluoresc 2020; 8:024005. [PMID: 32028271 PMCID: PMC8208541 DOI: 10.1088/2050-6120/ab7364] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/18/2019] [Accepted: 02/06/2020] [Indexed: 12/11/2022]
Abstract
In this review, we discuss methods and advancements in fluorescence lifetime imaging microscopy that permit measurements to be performed at faster speed and higher resolution than previously possible. We review fast single-photon timing technologies and the use of parallelized detection schemes to enable high-throughput and high content imaging applications. We appraise different technological implementations of fluorescence lifetime imaging, primarily in the time-domain. We also review combinations of fluorescence lifetime with other imaging modalities to capture multi-dimensional and correlative information from a single sample. Throughout the review, we focus on applications in biomedical research. We conclude with a critical outlook on current challenges and future opportunities in this rapidly developing field.
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Affiliation(s)
- Chetan Poudel
- Department of Chemical Engineering and Biotechnology,
Philippa Fawcett Drive, University of
Cambridge, Cambridge CB3 0AS, United
Kingdom
| | - Ioanna Mela
- Department of Chemical Engineering and Biotechnology,
Philippa Fawcett Drive, University of
Cambridge, Cambridge CB3 0AS, United
Kingdom
| | - Clemens F Kaminski
- Department of Chemical Engineering and Biotechnology,
Philippa Fawcett Drive, University of
Cambridge, Cambridge CB3 0AS, United
Kingdom
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17
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High-Throughput Fluorescence Assays for Ion Channels and GPCRs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:27-72. [DOI: 10.1007/978-3-030-12457-1_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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18
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Sen R, Hirvonen LM, Zhdanov A, Svihra P, Andersson-Engels S, Nomerotski A, Papkovsky D. New luminescence lifetime macro-imager based on a Tpx3Cam optical camera. BIOMEDICAL OPTICS EXPRESS 2020; 11:77-88. [PMID: 32010501 PMCID: PMC6968763 DOI: 10.1364/boe.11.000077] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/16/2019] [Accepted: 10/16/2019] [Indexed: 05/10/2023]
Abstract
The properties of a novel ultra-fast optical imager, Tpx3Cam, were investigated for macroscopic wide-field phosphorescent lifetime imaging (PLIM) applications. The camera is based on a novel optical sensor and Timepix3 readout chip with a time resolution of 1.6 ns, recording of photon arrival time and time over threshold for each pixel, and readout rate of 80 megapixels per second. In this study, we coupled the camera to an image intensifier, a 760 nm emission filter and a 50 mm lens, and with a super-bright 627nm LED providing pulsed excitation of a 18 × 18 mm sample area. The resulting macro-imager with compact and rigid optical alignment of its main components was characterised using planar phosphorescent O2 sensors and a resolution plate mask. Several acquisition and image processing algorithms were evaluated to optimise the system resolution and performance for the wide-field PLIM, followed by imaging a variety of phosphorescent samples. The new PLIM system looks promising, particularly for phosphorescence lifetime-based imaging of O2 in various chemical and biological samples.
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Affiliation(s)
- Rajannya Sen
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
- These authors contributed equally
| | - Liisa M. Hirvonen
- Centre for Microscopy, Characterisation and Analysis (CMCA), The University of Western Australia, Crawley WA 6009, Australia
- These authors contributed equally
| | - Alexander Zhdanov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Peter Svihra
- Department of Physics, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Prague 115 19, Czech Republic
- Department of Physics and Astronomy, School of Natural Sciences, The University of Manchester, Manchester M139PL, United Kingdom
| | | | - Andrei Nomerotski
- Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Dmitri Papkovsky
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
- Irish Photonics Integration Centre, Tyndall National Institute, Cork, Ireland
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19
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Leben R, Köhler M, Radbruch H, Hauser AE, Niesner RA. Systematic Enzyme Mapping of Cellular Metabolism by Phasor-Analyzed Label-Free NAD(P)H Fluorescence Lifetime Imaging. Int J Mol Sci 2019; 20:ijms20225565. [PMID: 31703416 PMCID: PMC6887798 DOI: 10.3390/ijms20225565] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 11/04/2019] [Indexed: 12/15/2022] Open
Abstract
In the past years, cellular metabolism of the immune system experienced a revival, as it has become clear that it is not merely responsible for the cellular energy supply, but also impacts on many signaling pathways and, thus, on diverse cellular functions. Label-free fluorescence lifetime imaging of the ubiquitous coenzymes NADH and NADPH (NAD(P)H-FLIM) makes it possible to monitor cellular metabolism in living cells and tissues and has already been applied to study metabolic changes both under physiologic and pathologic conditions. However, due to the complex distribution of NAD(P)H-dependent enzymes in cells, whose distribution continuously changes over time, a thorough interpretation of NAD(P)H-FLIM results, in particular, resolving the contribution of various enzymes to the overall metabolic activity, remains challenging. We developed a systematic framework based on angle similarities of the phase vectors and their length to analyze NAD(P)H-FLIM data of cells and tissues based on a generally valid reference system of highly abundant NAD(P)H-dependent enzymes in cells. By using our analysis framework, we retrieve information not only about the overall metabolic activity, i.e., the fraction of free to enzyme-bound NAD(P)H, but also identified the enzymes predominantly active within the sample at a certain time point with subcellular resolution. We verified the performance of the approach by applying NAD(P)H-FLIM on a stromal-like cell line and identified a different group of enzymes that were active in the cell nuclei as compared to the cytoplasm. As the systematic phasor-based analysis framework of label-free NAD(P)H-FLIM can be applied both in vitro and in vivo, it retains the unique power to enable dynamic enzyme-based metabolic investigations, at subcellular resolution, in genuine environments.
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Affiliation(s)
- Ruth Leben
- Biophysical Analytics, Deutsches Rheuma-Forschungszentrum (DRFZ), 10117 Berlin, Germany;
- Dynamic and Functional in vivo Imaging, Freie Universität Berlin, 14163 Berlin, Germany
- Correspondence: (R.L.); (R.A.N.); Tel.: +49-30-2846-0674 (R.L.); +49-30-2846-0708 (R.A.N.)
| | - Markus Köhler
- Biophysical Analytics, Deutsches Rheuma-Forschungszentrum (DRFZ), 10117 Berlin, Germany;
- Dynamic and Functional in vivo Imaging, Freie Universität Berlin, 14163 Berlin, Germany
| | - Helena Radbruch
- Institute for Neuropathology, Charité–Universitätsmedizin Berlin, 10117 Berlin, Germany;
| | - Anja E. Hauser
- Immune Dynamics, Deutsches Rheuma-Forschungszentrum (DRFZ), 10117 Berlin, Germany;
- Immunodynamics and Intravital Microscopy, Charité–Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Raluca A. Niesner
- Biophysical Analytics, Deutsches Rheuma-Forschungszentrum (DRFZ), 10117 Berlin, Germany;
- Dynamic and Functional in vivo Imaging, Freie Universität Berlin, 14163 Berlin, Germany
- Correspondence: (R.L.); (R.A.N.); Tel.: +49-30-2846-0674 (R.L.); +49-30-2846-0708 (R.A.N.)
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20
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Trinh AL, Ber S, Howitt A, Valls PO, Fries MW, Venkitaraman AR, Esposito A. Fast single-cell biochemistry: theory, open source microscopy and applications. Methods Appl Fluoresc 2019; 7:044001. [PMID: 31422954 PMCID: PMC7000240 DOI: 10.1088/2050-6120/ab3bd2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fluorescence lifetime sensing enables researchers to probe the physicochemical environment of a fluorophore providing a window through which we can observe the complex molecular make-up of the cell. Fluorescence lifetime imaging microscopy (FLIM) quantifies and maps cell biochemistry, a complex ensemble of dynamic processes. Unfortunately, typical high-resolution FLIM systems exhibit rather limited acquisition speeds, often insufficient to capture the time evolution of biochemical processes in living cells. Here, we describe the theoretical background that justifies the developments of high-speed single photon counting systems. We show that systems with low dead-times not only result in faster acquisition throughputs but also improved dynamic range and spatial resolution. We also share the implementation of hardware and software as an open platform, show applications of fast FLIM biochemical imaging on living cells and discuss strategies to balance precision and accuracy in FLIM. The recent innovations and commercialisation of fast time-domain FLIM systems are likely to popularise FLIM within the biomedical community, to impact biomedical research positively and to foster the adoption of other FLIM techniques as well. While supporting and indeed pursuing these developments, with this work we also aim to warn the community about the possible shortcomings of fast single photon counting techniques and to highlight strategies to acquire data of high quality.
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21
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Elbers D, Scholten A, Koch KW. Zebrafish Recoverin Isoforms Display Differences in Calcium Switch Mechanisms. Front Mol Neurosci 2018; 11:355. [PMID: 30323742 PMCID: PMC6172410 DOI: 10.3389/fnmol.2018.00355] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 09/11/2018] [Indexed: 12/29/2022] Open
Abstract
Primary steps in vertebrate vision occur in rod and cone cells of the retina and require precise molecular switches in excitation, recovery, and adaptation. In particular, recovery of the photoresponse and light adaptation processes are under control of neuronal Ca2+ sensor (NCS) proteins. Among them, the Ca2+ sensor recoverin undergoes a pronounced Ca2+-dependent conformational change, a prototypical so-called Ca2+-myristoyl switch, which allows selective targeting of G protein-coupled receptor kinase. Zebrafish (Danio rerio) has gained attention as a model organism in vision research. It expresses four different recoverin isoforms (zRec1a, zRec1b, zRec2a, and zRec2b) that are orthologs to the one known mammalian variant. The expression pattern of the four isoforms cover both rod and cone cells, but the differential distribution in cones points to versatile functions of recoverin in these cell types. Initial functional studies on zebrafish larvae indicate different Ca2+-sensitive working modes for zebrafish recoverins, but experimental evidence is lacking so far. The aims of the present study are (1) to measure specific Ca2+-sensing properties of the different recoverin isoforms, (2) to ask whether switch mechanisms triggered by Ca2+ resemble that one observed with mammalian recoverin, and (3) to investigate a possible impact of an attached myristoyl moiety. For addressing these questions, we employ fluorescence spectroscopy, surface plasmon resonance (SPR), dynamic light scattering, and equilibrium centrifugation. Exposure of hydrophobic amino acids, due to the myristoyl switch, differed among isoforms and depended also on the myristoylation state of the particular recoverin. Ca2+-induced rearrangement of the protein-water shell was for all variants less pronounced than for the bovine ortholog indicating either a modified Ca2+-myristoyl switch or no switch. Our results have implications for a step-by-step response of recoverin isoforms to changing intracellular Ca2+ during illumination.
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Affiliation(s)
- Dana Elbers
- Department of Neuroscience, Biochemistry, University of Oldenburg, Oldenburg, Germany
| | - Alexander Scholten
- Department of Neuroscience, Biochemistry, University of Oldenburg, Oldenburg, Germany
| | - Karl-Wilhelm Koch
- Department of Neuroscience, Biochemistry, University of Oldenburg, Oldenburg, Germany
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22
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Zhang C, Liu M, Liu S, Yang H, Zhao Q, Liu Z, He W. Phosphorescence Lifetime Imaging of Labile Zn 2+ in Mitochondria via a Phosphorescent Iridium(III) Complex. Inorg Chem 2018; 57:10625-10632. [PMID: 30102519 DOI: 10.1021/acs.inorgchem.8b01272] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Phosphorescence lifetime Zn2+ imaging possesses the advantage over normal fluorescence imaging in offering the more accurate temporal-spatial Zn2+ information. Herein, we report a new phosphorescent cyclometalated Ir(III) complex with a Zn2+-chelator bearing 1,10-phenanthrolin acting as ancillary ligand, Zin-IrDPA, which displays the specific Zn2+-induced enhancement of phosphorescence and phosphorescence lifetime, and the mitochondria-targeting ability. Moreover, its Zn2+-induced phosphorescence lifetime enhancement factor is not affected by medium lipophilicity, viscosity, polarity, and especially ambient oxygen. The reversible tracking of introduced exogenous labile Zn2+ in MCF-7 and HeLa cells via phosphorescence imaging and phosphorescence lifetime imaging (PLIM) have been realized with Zin-IrDPA. Moreover, PLIM with Zin-IrDPA is able to track the SNOC-stimulated endogenous Zn2+ release in mitochondria.
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Affiliation(s)
- Changli Zhang
- School of Environmental Science , Nanjing Xiaozhuang College , Nanjing 211171 , PR China
| | - Minsheng Liu
- School of Environmental Science , Nanjing Xiaozhuang College , Nanjing 211171 , PR China
| | - Shaoxian Liu
- School of Environmental Science , Nanjing Xiaozhuang College , Nanjing 211171 , PR China
| | - Hui Yang
- School of Environmental Science , Nanjing Xiaozhuang College , Nanjing 211171 , PR China
| | - Qiang Zhao
- Key Laboratory for Organic Electronics and Information Displays and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing University of Posts and Telecommunications (NUPT) , Nanjing 210023 , PR China
| | - Zhipeng Liu
- Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University (NanjingTech) , Nanjing 211816 , PR China
| | - Weijiang He
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210093 , PR China
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23
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Phasor-Based Endogenous NAD(P)H Fluorescence Lifetime Imaging Unravels Specific Enzymatic Activity of Neutrophil Granulocytes Preceding NETosis. Int J Mol Sci 2018; 19:ijms19041018. [PMID: 29596303 PMCID: PMC5979388 DOI: 10.3390/ijms19041018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/15/2018] [Accepted: 03/17/2018] [Indexed: 12/16/2022] Open
Abstract
Time-correlated single-photon counting combined with multi-photon laser scanning microscopy has proven to be a versatile tool to perform fluorescence lifetime imaging in biological samples and, thus, shed light on cellular functions, both in vitro and in vivo. Here, by means of phasor-analyzed endogenous NAD(P)H (nicotinamide adenine dinucleotide (phosphate)) fluorescence lifetime imaging, we visualize the shift in the cellular metabolism of healthy human neutrophil granulocytes during phagocytosis of Staphylococcus aureus pHrodo™ beads. We correlate this with the process of NETosis, i.e., trapping of pathogens by DNA networks. Hence, we are able to directly show the dynamics of NADPH oxidase activation and its requirement in triggering NETosis in contrast to other pathways of cell death and to decipher the dedicated spatio-temporal sequence between NADPH oxidase activation, nuclear membrane disintegration and DNA network formation. The endogenous FLIM approach presented here uniquely meets the increasing need in the field of immunology to monitor cellular metabolism as a basic mechanism of cellular and tissue functions.
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24
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Zheng K, Jensen TP, Rusakov DA. Monitoring intracellular nanomolar calcium using fluorescence lifetime imaging. Nat Protoc 2018; 13:581-597. [PMID: 29470463 DOI: 10.1038/nprot.2017.154] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nanomolar-range fluctuations of intracellular [Ca2+] are critical for brain cell function but remain difficult to measure. We have advanced a microscopy technique to monitor intracellular [Ca2+] in individual cells in acute brain slices (also applicable in vivo) using fluorescence lifetime imaging (FLIM) of the Ca2+-sensitive fluorescent indicator Oregon Green BAPTA1 (OGB-1). The OGB-1 fluorescence lifetime is sensitive to [Ca2+] within the 10-500 nM range but not to other factors such as viscosity, temperature, or pH. This protocol describes the requirements, setup, and calibration of the FLIM system required for OGB-1 imaging. We provide a step-by-step procedure for whole-cell OGB-1 loading and two-photon FLIM. We also describe how to analyze the obtained FLIM data using total photon count and gated-intensity record, a ratiometric photon-counting approach that provides a highly improved signal-to-noise ratio and greater sensitivity of absolute [Ca2+] readout. We demonstrate our technique in nerve cells in situ, and it is adaptable to other cell types and fluorescent indicators. This protocol requires a basic understanding of FLIM and experience in single-cell electrophysiology and cell imaging. Setting up the FLIM system takes ∼2 d, and OGB-1 loading, imaging, and data analysis take 2 d.
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Affiliation(s)
- Kaiyu Zheng
- UCL Institute of Neurology, University College London, London, UK
| | - Thomas P Jensen
- UCL Institute of Neurology, University College London, London, UK
| | - Dmitri A Rusakov
- UCL Institute of Neurology, University College London, London, UK
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25
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Zhang KY, Yu Q, Wei H, Liu S, Zhao Q, Huang W. Long-Lived Emissive Probes for Time-Resolved Photoluminescence Bioimaging and Biosensing. Chem Rev 2018; 118:1770-1839. [DOI: 10.1021/acs.chemrev.7b00425] [Citation(s) in RCA: 479] [Impact Index Per Article: 79.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Kenneth Yin Zhang
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P. R. China
| | - Qi Yu
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P. R. China
| | - Huanjie Wei
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P. R. China
| | - Shujuan Liu
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P. R. China
| | - Qiang Zhao
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P. R. China
| | - Wei Huang
- Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P. R. China
- Shaanxi
Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), Xi’an 710072, P. R. China
- Key
Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced
Materials (IAM), Jiangsu National Synergetic Innovation Center for
Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), Nanjing 211800, P. R. China
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26
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Fereidouni F, Gorpas D, Ma D, Fatakdawala H, Marcu L. Rapid fluorescence lifetime estimation with modified phasor approach and Laguerre deconvolution: a comparative study. Methods Appl Fluoresc 2017; 5:035003. [PMID: 28644150 PMCID: PMC6043162 DOI: 10.1088/2050-6120/aa7b62] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Fluorescence lifetime imaging has been shown to serve as a valuable tool for interrogating and diagnosis of biological tissue at a mesoscopic level. The ability to analyze fluorescence decay curves to extract lifetime values in real-time is crucial for clinical translation and applications such as tumor margin delineation or intracoronary imaging of atherosclerotic plaques. In this work, we compare the performance of two popular non-parametric (fit-free) methods for determining lifetime values from fluorescence decays in real-time-the Phasor approach and Laguerre deconvolution. We demonstrate results from simulated and experimental data to compare the accuracy and speed of both methods and their dependence on noise and model parameters.
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Affiliation(s)
- Farzad Fereidouni
- Department of Pathology and Laboratory Medicine, 4400 V Street, CA 95817, United States of America
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27
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Abstract
Introduction: This paper analyses the ability of single-photon avalanche diodes (SPADs) for neural imaging. The current trend in the production of SPADs moves toward the minimum dark count rate (DCR) and maximum photon detection probability (PDP). Moreover, the jitter response which is the main measurement characteristic for the timing uncertainty is progressing. Methods: The neural imaging process using SPADs can be performed by means of florescence lifetime imaging (FLIM), time correlated single-photon counting (TCSPC), positron emission tomography (PET), and single-photon emission computed tomography (SPECT). Results: This trend will result in more precise neural imaging cameras. While achieving low DCR SPADs is difficult in deep submicron technologies because of using higher doping profiles, higher PDPs are reported in green and blue part of light. Furthermore, the number of pixels integrated in the same chip is increasing with the technology progress which can result in the higher resolution of imaging. Conclusion: This study proposes implemented SPADs in Deep-submicron technologies to be used in neural imaging cameras, due to the small size pixels and higher timing accuracies.
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Affiliation(s)
- Mohammad Azim Karami
- Department of Electronic Engineering, School of Electrical Engineering, University of Science and Technology, Tehran, Iran
| | - Misagh Ansarian
- Department of Electronic Engineering, School of Electrical Engineering, University of Science and Technology, Tehran, Iran
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28
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Bremer D, Leben R, Mothes R, Radbruch H, Niesner R. Method to Detect the Cellular Source of Over-Activated NADPH Oxidases Using NAD(P)H Fluorescence Lifetime Imaging. ACTA ACUST UNITED AC 2017; 80:9.52.1-9.52.14. [PMID: 28369765 DOI: 10.1002/cpcy.20] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Fluorescence-lifetime imaging microscopy (FLIM) is a technique to generate images, in which the contrast is obtained by the excited-state lifetime of fluorescent molecules instead of their intensity and emission spectrum. The ubiquitous coenzymes NADH and NADPH, hereafter NAD(P)H, in cells show a short fluorescence lifetime ≈400 psec in the free-state and a longer fluorescence lifetime when bound to enzymes. The fluorescence lifetime of NAD(P)H in this state depends on the binding-site on the specific enzyme. In the case of NADPH bound to members of the NADPH oxidases family we measured a fluorescence lifetime of 3650 psec as compared to enzymes typically active in cells, in which case fluorescence lifetimes of ∼2000 psec are measured. Here we present a robust protocol based on NAD(P)H fluorescence lifetime imaging in isolated cells to distinguish between normally active enzymes and NADPH oxidases, mainly responsible for oxidative stress. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
- Daniel Bremer
- Biophysical Analytics, German Rheumatism Research Center, Leibniz Institute, Berlin, Germany.,Neuropathology Department, Charité - Universitätsmedizin, Berlin, Berlin, Germany
| | - Ruth Leben
- Biophysical Analytics, German Rheumatism Research Center, Leibniz Institute, Berlin, Germany
| | - Ronja Mothes
- Biophysical Analytics, German Rheumatism Research Center, Leibniz Institute, Berlin, Germany.,Neuropathology Department, Charité - Universitätsmedizin, Berlin, Berlin, Germany
| | - Helena Radbruch
- Neuropathology Department, Charité - Universitätsmedizin, Berlin, Berlin, Germany
| | - Raluca Niesner
- Biophysical Analytics, German Rheumatism Research Center, Leibniz Institute, Berlin, Germany
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29
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Ma Q, Ye L, Liu H, Shi Y, Zhou N. An overview of Ca 2+ mobilization assays in GPCR drug discovery. Expert Opin Drug Discov 2017; 12:511-523. [PMID: 28277837 DOI: 10.1080/17460441.2017.1303473] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Calcium ions (Ca2+) serve as a second messenger or universal signal transducer implicated in the regulation of a wide range of physiological processes. A change in the concentration of intracellular Ca2+ is an important step in intracellular signal transduction. G protein-coupled receptors (GPCRs), the largest and most versatile group of cell surface receptors, transduce extracellular signals into intracellular responses via their coupling to heterotrimeric G proteins. Since Ca2+ plays a crucial role in GPCR-induced signaling, measurement of intracellular Ca2+ has attracted more and more attention in GPCR-targeted drug discovery. Areas covered: This review focuses on the most popular functional assays measuring GPCRs-induced intracellular Ca2+ signaling. These include photoprotein-based, synthetic fluorescent indicator-based and genetically encoded calcium indicator (GECI)-based Ca2+ mobilization assays. A brief discussion of the design strategy of fluorescent probes in GPCR studies is also presented. Expert opinion: GPCR-mediated intracellular signaling is multidimensional. There is an urgent need for the development of multiple-readout screening assays capable of simultaneous detection of biased signaling and screening of both agonists and antagonists in the same assay. It is also necessary to develop GECIs offering low cost and consistent assays suitable for investigating GPCR activation in vivo.
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Affiliation(s)
- Qiang Ma
- a College of Life Sciences, Zijingang Campus , Zhejiang University, Institute of Biochemistry and Molecular Biology , Hangzhou , Zhejiang , China
| | - Lingyan Ye
- a College of Life Sciences, Zijingang Campus , Zhejiang University, Institute of Biochemistry and Molecular Biology , Hangzhou , Zhejiang , China
| | - Hongxia Liu
- b Department of Internal Medicine , Edong Healthcare Group , Huangshi , Hubei , China
| | - Ying Shi
- a College of Life Sciences, Zijingang Campus , Zhejiang University, Institute of Biochemistry and Molecular Biology , Hangzhou , Zhejiang , China
| | - Naiming Zhou
- a College of Life Sciences, Zijingang Campus , Zhejiang University, Institute of Biochemistry and Molecular Biology , Hangzhou , Zhejiang , China
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30
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Minge D, Senkov O, Kaushik R, Herde MK, Tikhobrazova O, Wulff AB, Mironov A, van Kuppevelt TH, Oosterhof A, Kochlamazashvili G, Dityatev A, Henneberger C. Heparan Sulfates Support Pyramidal Cell Excitability, Synaptic Plasticity, and Context Discrimination. Cereb Cortex 2017; 27:903-918. [PMID: 28119345 PMCID: PMC5390399 DOI: 10.1093/cercor/bhx003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 12/04/2016] [Accepted: 01/04/2017] [Indexed: 02/06/2023] Open
Abstract
Heparan sulfate (HS) proteoglycans represent a major component of the extracellular matrix and are critical for brain development. However, their function in the mature brain remains to be characterized. Here, acute enzymatic digestion of HS side chains was used to uncover how HSs support hippocampal function in vitro and in vivo. We found that long-term potentiation (LTP) of synaptic transmission at CA3-CA1 Schaffer collateral synapses was impaired after removal of highly sulfated HSs with heparinase 1. This reduction was associated with decreased Ca2+ influx during LTP induction, which was the consequence of a reduced excitability of CA1 pyramidal neurons. At the subcellular level, heparinase treatment resulted in reorganization of the distal axon initial segment, as detected by a reduction in ankyrin G expression. In vivo, digestion of HSs impaired context discrimination in a fear conditioning paradigm and oscillatory network activity in the low theta band after fear conditioning. Thus, HSs maintain neuronal excitability and, as a consequence, support synaptic plasticity and learning.
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Affiliation(s)
- Daniel Minge
- Institute of Cellular Neurosciences, University of Bonn Medical School, 53105 Bonn, Germany
| | - Oleg Senkov
- German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Rahul Kaushik
- German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Michel K. Herde
- Institute of Cellular Neurosciences, University of Bonn Medical School, 53105 Bonn, Germany
| | - Olga Tikhobrazova
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genova, Italy
- Department of Neurotechnology, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
| | - Andreas B. Wulff
- Institute of Cellular Neurosciences, University of Bonn Medical School, 53105 Bonn, Germany
| | - Andrey Mironov
- Department of Neurotechnology, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
- Central Research Laboratory, Nizhny Novgorod State Medical Academy, 603005 Nizhny Novgorod, Russia
| | - Toin H. van Kuppevelt
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Arie Oosterhof
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Gaga Kochlamazashvili
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genova, Italy
- Department of Molecular Pharmacology and Cell Biology, Leibniz-Institut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Alexander Dityatev
- German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, 16163 Genova, Italy
- Department of Neurotechnology, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia
- Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, 39120 Magdeburg, Germany
| | - Christian Henneberger
- Institute of Cellular Neurosciences, University of Bonn Medical School, 53105 Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany
- Institute of Neurology, University College London, London WC1N 3BG, UK
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31
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Brinks D, Adam Y, Kheifets S, Cohen AE. Painting with Rainbows: Patterning Light in Space, Time, and Wavelength for Multiphoton Optogenetic Sensing and Control. Acc Chem Res 2016; 49:2518-2526. [PMID: 27786461 DOI: 10.1021/acs.accounts.6b00415] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Photons are a fascinating reagent, flowing and reacting quite differently compared to more massive and less ephemeral particles of matter. The optogenetic palette comprises an ever growing set of light-responsive proteins, which open the possibility of using light to perturb and to measure biological processes with great precision in space and time. Yet there are limits on what light can achieve. Diffraction limits the smallest features, and scattering in tissue limits the largest. Photobleaching, diffusion of photogenerated products, and optical crosstalk between overlapping absorption spectra further muddy the optogenetic picture, particularly when one wants to use multiple optogenetic tools simultaneously. But these obstacles are surmountable. Most light-responsive proteins and small molecules undergo more than one light-driven transition, often with different action spectra and kinetics. By overlapping multiple laser beams, carefully patterned in space, time, and wavelength, one can steer molecules into fluorescent or nonfluorescent, active or inactive conformations. By doing so, one can often circumvent the limitations of simple one-photon excitation and achieve new imaging and stimulation capabilities. These include subdiffraction spatial resolution, optical sectioning, robustness to light scattering, and multiplexing of more channels than can be achieved with simple one-photon excitation. The microbial rhodopsins are a particularly rich substrate for this type of multiphoton optical control. The natural diversity of these proteins presents a huge range of starting materials. The spectroscopy and photocycles of microbial rhodopsins are relatively well understood, providing states with absorption maxima across the visible spectrum, which can be accessed on experimentally convenient time scales. A long history of mutational studies in microbial rhodopsins allows semirational protein engineering. Mutants of Archaerhodopsin 3 (Arch) come in all the colors of the rainbow. In a solution of purified Arch-eGFP, a focused green laser excites eGFP fluorescence throughout the laser path, while a focused red laser excites fluorescence of Arch only near the focus, indicative of multiphoton fluorescence. This nonlinearity occurs at a laser intensity ∼1010-fold lower than in conventional two-photon microscopy! The mutant Arch(D95H) shows photoswitchable optical bistability. In a lawn of E. coli expressing this mutant, illumination with patterned blue light converts the molecule into a state that is fluorescent. Illumination with red light excites this fluorescence, and gradually resets the molecules back to the non-fluorescent state. This review describes the new types of molecular logic that can be implemented with multi-photon control of microbial rhodopsins, from whole-brain activity mapping to measurements of absolute membrane voltage. Part of our goal in this Account is to describe recent work in nonlinear optogenetics, but we also present a variety of interesting things one could do if only the right optogenetic molecules were available. This latter component is intended to inspire future spectroscopic, protein discovery, and protein engineering work.
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Affiliation(s)
- Daan Brinks
- Department
of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Yoav Adam
- Department
of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Simon Kheifets
- Department
of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Adam E. Cohen
- Department
of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- Howard
Hughes Medical Institute, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
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32
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Zhang Y, Cuyt A, Lee WS, Lo Bianco G, Wu G, Chen Y, Li DDU. Towards unsupervised fluorescence lifetime imaging using low dimensional variable projection. OPTICS EXPRESS 2016; 24:26777-26791. [PMID: 27857408 DOI: 10.1364/oe.24.026777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Analyzing large fluorescence lifetime imaging (FLIM) data is becoming overwhelming; the latest FLIM systems easily produce massive amounts of data, making an efficient analysis more challenging than ever. In this paper we propose the combination of a custom-fit variable projection method, with a Laguerre expansion based deconvolution, to analyze bi-exponential data obtained from time-domain FLIM systems. Unlike nonlinear least squares methods, which require a suitable initial guess from an experienced researcher, the new method is free from manual interventions and hence can support automated analysis. Monte Carlo simulations are carried out on synthesized FLIM data to demonstrate the performance compared to other approaches. The performance is also illustrated on real-life FLIM data obtained from the study of autofluorescence of daisy pollen and the endocytosis of gold nanorods (GNRs) in living cells. In the latter, the fluorescence lifetimes of the GNRs are much shorter than the full width at half maximum of the instrument response function. Overall, our proposed method contains simple steps and shows great promise in realising automated FLIM analysis of large data sets.
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33
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Won Y, Park B, Kim I, Lee S. Fluorescence lifetime measurement with confocal endomicroscopy for direct analysis of tissue biochemistry in vivo. Heliyon 2016; 2:e00139. [PMID: 27547835 PMCID: PMC4983142 DOI: 10.1016/j.heliyon.2016.e00139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 07/06/2016] [Accepted: 08/02/2016] [Indexed: 12/20/2022] Open
Abstract
Confocal endomicroscopy is a powerful tool for in vivo real-time imaging at cellular resolution inside a living body without tissue resection. Microscopic fluorescence lifetime measurement can provide information about localized biochemical conditions such as pH and the concentrations of oxygen and calcium. We hypothesized that combining these techniques could assist accurate cancer discrimination by providing both biochemical and morphological information. We designed a dual-mode experimental setup for confocal endomicroscopic imaging and fluorescence lifetime measurement and applied it to a mouse xenograft model of activated human pancreatic cancer generated by subcutaneous injection of AsPC-1 tumor cells. Using this method with pH-sensitive sodium fluorescein injection, we demonstrated discrimination between normal and cancerous tissues in a living mouse. With further development, this method may be useful for clinical cancer detection.
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Affiliation(s)
- Youngjae Won
- Medical Device Development Center, Osong Medical Innovation Foundation, Cheongju, Chungbuk, 28160, Republic of Korea
| | - Byungjun Park
- Medical Device Development Center, Osong Medical Innovation Foundation, Cheongju, Chungbuk, 28160, Republic of Korea
| | - Inwook Kim
- Catholic Research Institute of Medical Science, The Catholic University of Korea, Seoul, 137-071, Republic of Korea
| | - Seungrag Lee
- Medical Device Development Center, Osong Medical Innovation Foundation, Cheongju, Chungbuk, 28160, Republic of Korea
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34
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Bower AJ, Arp Z, Zhao Y, Li J, Chaney EJ, Marjanovic M, Hughes-Earle A, Boppart SA. Longitudinal in vivo tracking of adverse effects following topical steroid treatment. Exp Dermatol 2016; 25:362-7. [PMID: 26739196 DOI: 10.1111/exd.12932] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2015] [Indexed: 12/24/2022]
Abstract
Topical steroids are known for their anti-inflammatory properties and are commonly prescribed to treat many adverse skin conditions such as eczema and psoriasis. While these treatments are known to be effective, adverse effects including skin atrophy are common. In this study, the progression of these effects is investigated in an in vivo mouse model using multimodal optical microscopy. Utilizing a system capable of performing two-photon excitation fluorescence microscopy (TPEF) of reduced nicotinamide adenine dinucleotide (NADH) to visualize the epidermal cell layers and second harmonic generation (SHG) microscopy to identify collagen in the dermis, these processes can be studied at the cellular level. Fluorescence lifetime imaging microscopy (FLIM) is also utilized to image intracellular NADH levels to obtain molecular information regarding metabolic activity following steroid treatment. In this study, fluticasone propionate (FP)-treated, mometasone furoate (MF)-treated and untreated animals were imaged longitudinally using a custom-built multimodal optical microscope. Prolonged steroid treatment over the course of 21 days is shown to result in a significant increase in mean fluorescence lifetime of NADH, suggesting a faster rate of maturation of epidermal keratinocytes. Alterations to collagen organization and the structural microenvironment are also observed. These results give insight into the structural and biochemical processes of skin atrophy associated with prolonged steroid treatment.
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Affiliation(s)
- Andrew J Bower
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Zane Arp
- GlaxoSmithKline, King of Prussia, PA, USA
| | - Youbo Zhao
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Joanne Li
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Eric J Chaney
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Marina Marjanovic
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | | | - Stephen A Boppart
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Internal Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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35
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Nakabayashi T, Ohta N. Sensing of intracellular environments by fluorescence lifetime imaging of exogenous fluorophores. ANAL SCI 2016; 31:275-85. [PMID: 25864670 DOI: 10.2116/analsci.31.275] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Fluorescence lifetime imaging (FLIM) has been recognized as a powerful microscopy technique to examine environments in living systems. The fluorescence lifetime does not depend on the photobleaching and optical conditions, which allows us to obtain quantitative information on intracellular environments by analyzing the fluorescence lifetime. A variety of exogenous fluorophores have been applied in FLIM measurements to examine cellular processes. Information on the correlation between the fluorescence lifetime and the physiological parameters is essential to elucidate the cellular environments from the fluorescence lifetime measurements of exogenous fluorophores. In this review, exogenous fluorophores used for lifetime-based sensing are summarized, with the expectation that it becomes a basis for selecting the fluorophore used to investigate the intracellular environment with FLIM. Experimental results of the intracellular sensing of pH, metal ions, oxygen, viscosity, and other physiological parameters on the basis of the FLIM measurements are described along with a brief explanation of the mechanism of the change in the fluorescence lifetime.
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36
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Mossakowski AA, Pohlan J, Bremer D, Lindquist R, Millward JM, Bock M, Pollok K, Mothes R, Viohl L, Radbruch M, Gerhard J, Bellmann-Strobl J, Behrens J, Infante-Duarte C, Mähler A, Boschmann M, Rinnenthal JL, Füchtemeier M, Herz J, Pache FC, Bardua M, Priller J, Hauser AE, Paul F, Niesner R, Radbruch H. Tracking CNS and systemic sources of oxidative stress during the course of chronic neuroinflammation. Acta Neuropathol 2015; 130:799-814. [PMID: 26521072 PMCID: PMC4654749 DOI: 10.1007/s00401-015-1497-x] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 10/15/2015] [Accepted: 10/15/2015] [Indexed: 11/30/2022]
Abstract
The functional dynamics and cellular sources of oxidative stress are central to understanding MS pathogenesis but remain elusive, due to the lack of appropriate detection methods. Here we employ NAD(P)H fluorescence lifetime imaging to detect functional NADPH oxidases (NOX enzymes) in vivo to identify inflammatory monocytes, activated microglia, and astrocytes expressing NOX1 as major cellular sources of oxidative stress in the central nervous system of mice affected by experimental autoimmune encephalomyelitis (EAE). This directly affects neuronal function in vivo, indicated by sustained elevated neuronal calcium. The systemic involvement of oxidative stress is mirrored by overactivation of NOX enzymes in peripheral CD11b+ cells in later phases of both MS and EAE. This effect is antagonized by systemic intake of the NOX inhibitor and anti-oxidant epigallocatechin-3-gallate. Together, this persistent hyper-activation of oxidative enzymes suggests an “oxidative stress memory” both in the periphery and CNS compartments, in chronic neuroinflammation.
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Affiliation(s)
- Agata A Mossakowski
- German Rheumatism Research Center, Berlin, Germany
- Department of Neurology, NeuroCure Clinical Research Center, Clinical and Experimental Multiple Sclerosis Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Institut für Neuropathologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Julian Pohlan
- German Rheumatism Research Center, Berlin, Germany
- Institut für Neuropathologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Intravital Imaging and Immune Dynamics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | | | - Jason M Millward
- Institute for Medical Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Markus Bock
- Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Karolin Pollok
- Institut für Neuropathologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Intravital Imaging and Immune Dynamics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ronja Mothes
- Institut für Neuropathologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Intravital Imaging and Immune Dynamics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Leonard Viohl
- Institut für Neuropathologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Intravital Imaging and Immune Dynamics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Moritz Radbruch
- German Rheumatism Research Center, Berlin, Germany
- Institut für Neuropathologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Judith Bellmann-Strobl
- Department of Neurology, NeuroCure Clinical Research Center, Clinical and Experimental Multiple Sclerosis Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Janina Behrens
- Department of Neurology, NeuroCure Clinical Research Center, Clinical and Experimental Multiple Sclerosis Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Carmen Infante-Duarte
- Institute for Medical Immunology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Anja Mähler
- Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Boschmann
- Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jan Leo Rinnenthal
- Institut für Neuropathologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Josephine Herz
- Department of Paediatrics I, Neonatology, University Hospital Essen, Essen, 45122, Germany
| | - Florence C Pache
- German Rheumatism Research Center, Berlin, Germany
- Department of Neurology, NeuroCure Clinical Research Center, Clinical and Experimental Multiple Sclerosis Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Intravital Imaging and Immune Dynamics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Josef Priller
- Department of Neuropsychiatry and Laboratory of Molecular Psychiatry, Charité-Universitätsmedizin Berlin, Cluster of Excellence NeuroCure and BIH, Berlin, Germany
| | - Anja E Hauser
- German Rheumatism Research Center, Berlin, Germany
- Intravital Imaging and Immune Dynamics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Friedemann Paul
- Department of Neurology, NeuroCure Clinical Research Center, Clinical and Experimental Multiple Sclerosis Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Experimental and Clinical Research Center, Max Delbrueck Center for Molecular Medicine and Charité-Universitätsmedizin Berlin, Berlin, Germany
| | | | - Helena Radbruch
- Institut für Neuropathologie, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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37
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Burdikova Z, Svindrych Z, Pala J, Hickey CD, Wilkinson MG, Panek J, Auty MAE, Periasamy A, Sheehan JJ. Measurement of pH micro-heterogeneity in natural cheese matrices by fluorescence lifetime imaging. Front Microbiol 2015; 6:183. [PMID: 25798136 PMCID: PMC4351631 DOI: 10.3389/fmicb.2015.00183] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 02/19/2015] [Indexed: 11/26/2022] Open
Abstract
Cheese, a product of microbial fermentation may be defined as a protein matrix entrapping fat, moisture, minerals and solutes as well as dispersed bacterial colonies. The growth and physiology of bacterial cells in these colonies may be influenced by the microenvironment around the colony, or alternatively the cells within the colony may modify the microenvironment (e.g., pH, redox potential) due to their metabolic activity. While cheese pH may be measured at macro level there remains a significant knowledge gap relating to the degree of micro-heterogeneity of pH within the cheese matrix and its relationship with microbial, enzymatic and physiochemical parameters and ultimately with cheese quality, consistency and ripening patterns. The pH of cheese samples was monitored both at macroscopic scale and at microscopic scale, using a non-destructive microscopic technique employing C-SNARF-4 and Oregon Green 488 fluorescent probes. The objectives of this work were to evaluate the suitability of these dyes for microscale pH measurements in natural cheese matrices and to enhance the sensitivity and extend the useful pH range of these probes using fluorescence lifetime imaging (FLIM). In particular, fluorescence lifetime of Oregon Green 488 proved to be sensitive probe to map pH micro heterogeneity within cheese matrices. Good agreement was observed between macroscopic scale pH measurement by FLIM and by traditional pH methods, but in addition considerable localized microheterogeneity in pH was evident within the curd matrix with pH range between 4.0 and 5.5. This technique provides significant potential to further investigate the relationship between cheese matrix physico-chemistry and bacterial metabolism during cheese manufacture and ripening.
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Affiliation(s)
| | - Zdenek Svindrych
- Department of Biology, W. M. Keck Center for Cellular Imaging, University of Virginia Charlottesville, VA, USA
| | - Jan Pala
- Department of Sport Medicine, Third Faculty of Medicine, Charles University Prague, Czech Republic
| | - Cian D Hickey
- Teagasc Food Research Centre Moorepark, Fermoy, Ireland
| | - Martin G Wilkinson
- Department of Life Sciences, Faculty of Science and Engineering, University of Limerick Limerick, Ireland
| | - Jiri Panek
- Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic Prague, Czech Republic
| | - Mark A E Auty
- Teagasc Food Research Centre Moorepark, Fermoy, Ireland
| | - Ammasi Periasamy
- Department of Biology, W. M. Keck Center for Cellular Imaging, University of Virginia Charlottesville, VA, USA
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38
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Kantner K, Ashraf S, Carregal-Romero S, Carrillo-Carrion C, Collot M, Del Pino P, Heimbrodt W, De Aberasturi DJ, Kaiser U, Kazakova LI, Lelle M, de Baroja NM, Montenegro JM, Nazarenus M, Pelaz B, Peneva K, Gil PR, Sabir N, Schneider LM, Shabarchina LI, Sukhorukov GB, Vazquez M, Yang F, Parak WJ. Particle-based optical sensing of intracellular ions at the example of calcium - what are the experimental pitfalls? SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:896-904. [PMID: 25504784 DOI: 10.1002/smll.201402110] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/24/2014] [Indexed: 06/04/2023]
Abstract
Colloidal particles with fluorescence read-out are commonly used as sensors for the quantitative determination of ions. Calcium, for example, is a biologically highly relevant ion in signaling, and thus knowledge of its spatio-temporal distribution inside cells would offer important experimental data. However, the use of particle-based intracellular sensors for ion detection is not straightforward. Important associated problems involve delivery and intracellular location of particle-based fluorophores, crosstalk of the fluorescence read-out with pH, and spectral overlap of the emission spectra of different fluorophores. These potential problems are outlined and discussed here with selected experimental examples. Potential solutions are discussed and form a guideline for particle-based intracellular imaging of ions.
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Affiliation(s)
- Karsten Kantner
- Fachbereich Physik, Philipps- Universität Marburg, Marburg, Germany
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Nedbal J, Visitkul V, Ortiz-Zapater E, Weitsman G, Chana P, Matthews DR, Ng T, Ameer-Beg SM. Time-domain microfluidic fluorescence lifetime flow cytometry for high-throughput Förster resonance energy transfer screening. Cytometry A 2015; 87:104-18. [PMID: 25523156 PMCID: PMC4440390 DOI: 10.1002/cyto.a.22616] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 11/12/2014] [Accepted: 12/03/2014] [Indexed: 01/22/2023]
Abstract
Sensing ion or ligand concentrations, physico-chemical conditions, and molecular dimerization or conformation change is possible by assays involving fluorescent lifetime imaging. The inherent low throughput of imaging impedes rigorous statistical data analysis on large cell numbers. We address this limitation by developing a fluorescence lifetime-measuring flow cytometer for fast fluorescence lifetime quantification in living or fixed cell populations. The instrument combines a time-correlated single photon counting epifluorescent microscope with microfluidics cell-handling system. The associated computer software performs burst integrated fluorescence lifetime analysis to assign fluorescence lifetime, intensity, and burst duration to each passing cell. The maximum safe throughput of the instrument reaches 3,000 particles per minute. Living cells expressing spectroscopic rulers of varying peptide lengths were distinguishable by Förster resonant energy transfer measured by donor fluorescence lifetime. An epidermal growth factor (EGF)-stimulation assay demonstrated the technique's capacity to selectively quantify EGF receptor phosphorylation in cells, which was impossible by measuring sensitized emission on a standard flow cytometer. Dual-color fluorescence lifetime detection and cell-specific chemical environment sensing were exemplified using di-4-ANEPPDHQ, a lipophilic environmentally sensitive dye that exhibits changes in its fluorescence lifetime as a function of membrane lipid order. To our knowledge, this instrument opens new applications in flow cytometry which were unavailable due to technological limitations of previously reported fluorescent lifetime flow cytometers. The presented technique is sensitive to lifetimes of most popular fluorophores in the 0.5-5 ns range including fluorescent proteins and is capable of detecting multi-exponential fluorescence lifetime decays. This instrument vastly enhances the throughput of experiments involving fluorescence lifetime measurements, thereby providing statistically significant quantitative data for analysis of large cell populations. © 2014 International Society for Advancement of Cytometry.
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Affiliation(s)
- Jakub Nedbal
- Division of Cancer Studies, King's College LondonUnited Kingdom
- Randall Division of Cell and Molecular Biophysics, King's College LondonUnited Kingdom
| | - Viput Visitkul
- Randall Division of Cell and Molecular Biophysics, King's College LondonUnited Kingdom
| | - Elena Ortiz-Zapater
- Division of Asthma, Allergy & Lung Biology, King's College LondonUnited Kingdom
| | | | - Prabhjoat Chana
- Immune Monitoring Laboratory, NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College LondonUnited Kingdom
| | - Daniel R Matthews
- Queensland Brain Institute, The University of QueenslandSt Lucia, Australia
| | - Tony Ng
- Division of Cancer Studies, King's College LondonUnited Kingdom
- Randall Division of Cell and Molecular Biophysics, King's College LondonUnited Kingdom
- UCL Cancer Institute, University College LondonUnited Kingdom
| | - Simon M Ameer-Beg
- Division of Cancer Studies, King's College LondonUnited Kingdom
- Randall Division of Cell and Molecular Biophysics, King's College LondonUnited Kingdom
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Sun Y, Periasamy A. Localizing protein-protein interactions in living cells using fluorescence lifetime imaging microscopy. Methods Mol Biol 2015; 1251:83-107. [PMID: 25391796 DOI: 10.1007/978-1-4939-2080-8_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In the past decade, advances in fluorescence lifetime imaging have extensively applied in the life sciences, from fundamental biological investigations to advanced clinical diagnosis. Fluorescence lifetime imaging microscopy (FLIM) is now routinely used in the biological sciences to monitor dynamic signaling events inside living cells, e.g., Protein-Protein interactions. In this chapter, we describe the calibration of both time-correlated single-photon counting (TCSPC) and frequency domain (FD) FLIM systems and the acquisition and analysis of FLIM-FRET data for investigating Protein-Protein interactions in living cells.
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Affiliation(s)
- Yuansheng Sun
- W.M. Keck Center for Cellular Imaging, Biology, University of Virginia, B005 Physical and Life Sciences Building, White Head Road, Charlottesville, VA, 22904, USA
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Zhuo Y, Solntsev KM, Reddish F, Tang S, Yang JJ. Effect of Ca²⁺ on the steady-state and time-resolved emission properties of the genetically encoded fluorescent sensor CatchER. J Phys Chem B 2014; 119:2103-11. [PMID: 24836743 PMCID: PMC4329989 DOI: 10.1021/jp501707n] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
We
previously designed a calcium sensor CatchER (a GFP-based Calcium
sensor for detecting high concentrations in the high calcium concentration
environment such as ER) with a capability for monitoring calcium ion
responses in various types of cells. Calcium binding to CatchER induces
the ratiometric changes in the absorption spectra, as well as an increase
in fluorescence emission at 510 nm upon excitation at both 395 and
488 nm. Here, we have applied the combination of the steady-state
and time-resolved optical methods and Hydrogen/Deuterium isotope exchange
to understand the origin of such calcium-induced optical property
changes of CatchER. We first demonstrated that calcium binding results
in a 44% mean fluorescence lifetime increase of the indirectly excited
anionic chromophore. Thus, CatchER is the first protein-based calcium
indicator with the single fluorescent moiety to show the direct correlation
between the lifetime and calcium binding. Calcium exhibits a strong
inhibition on the excited-state proton transfer nonadiabatic geminate
recombination in protic (vs deuteric) medium. Analysis of CatchER
crystal structures and the MD simulations reveal the proton transfer
mechanism in which the disrupted proton migration path in CatchER
is rescued by calcium binding. Our finding provides important insights
for a strategy to design calcium sensors and suggests that CatchER
could be a useful probe for FLIM imaging of calcium in situ.
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Affiliation(s)
- You Zhuo
- Department of Chemistry, Georgia State University , Atlanta, Georgia 30303, United States
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43
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Abdul Rahim NA, Pelet S, Mofrad MRK, So PTC, Kamm RD. Quantifying intracellular protein binding thermodynamics during mechanotransduction based on FRET spectroscopy. Methods 2014; 66:208-21. [PMID: 24184188 PMCID: PMC4094350 DOI: 10.1016/j.ymeth.2013.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 09/24/2013] [Accepted: 10/12/2013] [Indexed: 11/29/2022] Open
Abstract
Mechanical force modulates myriad cellular functions including migration, alignment, proliferation, and gene transcription. Mechanotransduction, the transmission of mechanical forces and its translation into biochemical signals, may be mediated by force induced protein conformation changes, subsequently modulating protein signaling. For the paxillin and focal adhesion kinase interaction, we demonstrate that force-induced changes in protein complex conformation, dissociation constant, and binding Gibbs free energy can be quantified by lifetime-resolved fluorescence energy transfer microscopy combined with intensity imaging calibrated by fluorescence correlation spectroscopy. Comparison with in vitro data shows that this interaction is allosteric in vivo. Further, spatially resolved imaging and inhibitor assays show that this protein interaction and its mechano-sensitivity are equal in the cytosol and in the focal adhesions complexes indicating that the mechano-sensitivity of this interaction must be mediated by soluble factors but not based on protein tyrosine phosphorylation.
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Affiliation(s)
- Nur Aida Abdul Rahim
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United states
| | - Serge Pelet
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United States; Department of Fundamental Microbiology, University of Lausanne, Biophore Building, Room 2406, CH-1015 Lausanne, Switzerland
| | - Mohammad R K Mofrad
- Department of Bioengineering, University of California Berkeley, 306 Stanley Hall MC #1762, Berkeley, CA 94720-1762, United States
| | - Peter T C So
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United states; Department of Biological Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United States; Laser Biomedical Research Center, A NIH NIBIB Research Resource, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United States.
| | - Roger D Kamm
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United states; Department of Biological Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United States
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Diversity of astroglial functions alludes to subcellular specialisation. Trends Neurosci 2014; 37:228-42. [PMID: 24631033 DOI: 10.1016/j.tins.2014.02.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 02/12/2014] [Accepted: 02/13/2014] [Indexed: 01/23/2023]
Abstract
Rapid signal exchange between astroglia and neurons has emerged as an essential element of neural circuits of the brain. However, the increasing variety of mechanisms contributing to this signalling appears to be facing a conceptual stalemate. The communication medium of astroglia involves intracellular [Ca(2+)] waves, which until recently have been associated with slow, global [Ca(2+)] rises. How such a uniform trigger could handle fast and diverse molecular messages remains unexplained. Recent studies have, however, revealed a variety of apparently independent Ca(2+) activities within individual astrocytic compartments, also indicating the prevalence of subcellular segregation for some signalling mechanisms. These signs of intracellular compartmentalisation might provide the key to the multitude of adaptive roles played by astroglia.
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Sagolla K, Löhmannsröben HG, Hille C. Time-resolved fluorescence microscopy for quantitative Ca2+ imaging in living cells. Anal Bioanal Chem 2013; 405:8525-37. [DOI: 10.1007/s00216-013-7290-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 07/31/2013] [Accepted: 08/01/2013] [Indexed: 11/28/2022]
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Timing and operating mode design for time-gated fluorescence lifetime imaging microscopy. ScientificWorldJournal 2013; 2013:801901. [PMID: 23864834 PMCID: PMC3707217 DOI: 10.1155/2013/801901] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Accepted: 06/02/2013] [Indexed: 11/17/2022] Open
Abstract
Steady-state fluorence imaging and time-resolved fluorescence imaging are two important areas in fluorescence imaging research. Fluorescence lifetime imaging is an absolute measurement method which is independent of excitation laser intensity, fluorophore concentration, and photobleaching compared to fluorescence intensity imaging techniques. Time-gated fluorescence lifetime imaging microscopy (FLIM) can provide high resolution and high imaging frame during mature FLIM methods. An abstract time-gated FLIM model was given, and important temporal parameters are shown as well. Aiming at different applications of steady and transient fluorescence processes, two different operation modes, timing and lifetime computing algorithm are designed. High resolution and high frame can be achieved by one-excitation one-sampling mode and least square algorithm for steady imaging applications. Correspondingly, one-excitation two-sampling mode and rapid lifetime determination algorithm contribute to transient fluorescence situations.
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Fereidouni F, Reitsma K, Gerritsen HC. High speed multispectral fluorescence lifetime imaging. OPTICS EXPRESS 2013; 21:11769-82. [PMID: 23736399 DOI: 10.1364/oe.21.011769] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We report a spectrally resolved fluorescence lifetime imaging system based on time gated single photon detection with a fixed gate width of 200 ps and 7 spectral channels. Time gated systems can operate at high count rates but usually have large gate widths and sample only part of the fluorescence decay curve. In the system presented in this work, the fluorescence signal is sampled using a high speed transceiver. An error analysis is carried out to characterize the performance of both lifetime and spectral detection. The effect of gate width and spectral channel width on the accuracy of estimated lifetimes and spectral widths is described. The performance of the whole instrument is evaluated at count rates of up to 12 MHz. Accurate fluorescence lifetimes (error < 2%) are recorded at count rates as high as 5 MHz. This is limited by the PMT performance, not by the electronics. Analysis of the large spectral lifetime image sets is challenging and time-consuming. Here, we demonstrate the use of lifetime and spectral phasors for analyzing images of fibroblast cells with 2 different labeled components. The phasor approach provides a fast and intuitive way of analyzing the results of spectrally resolved fluorescence lifetime imaging experiments.
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Affiliation(s)
- Farzad Fereidouni
- Molecular Biophysics, Debye Institute, Utrecht University, Utrecht, The Netherlands
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Vergen J, Hecht C, Zholudeva LV, Marquardt MM, Hallworth R, Nichols MG. Metabolic imaging using two-photon excited NADH intensity and fluorescence lifetime imaging. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:761-70. [PMID: 22832200 PMCID: PMC3842212 DOI: 10.1017/s1431927612000529] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Metabolism and mitochondrial dysfunction are known to be involved in many different disease states. We have employed two-photon fluorescence imaging of intrinsic mitochondrial reduced nicotinamide adenine dinucleotide (NADH) to quantify the metabolic state of several cultured cell lines, multicell tumor spheroids, and the intact mouse organ of Corti. Historically, fluorescence intensity has commonly been used as an indicator of the NADH concentration in cells and tissues. More recently, fluorescence lifetime imaging has revealed that changes in metabolism produce not only changes in fluorescence intensity, but also significant changes in the lifetimes and concentrations of free and enzyme-bound pools of NADH. Since NADH binding changes with metabolic state, this approach presents a new opportunity to track the cellular metabolic state.
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Affiliation(s)
- Jorge Vergen
- Department of Physics, Creighton University, 2500 California Plaza, Omaha, NE 68178
| | - Clifford Hecht
- Department of Physics, Creighton University, 2500 California Plaza, Omaha, NE 68178
| | | | - Meg M. Marquardt
- Department of Physics, Creighton University, 2500 California Plaza, Omaha, NE 68178
| | - Richard Hallworth
- Department of Biomedical Sciences, Creighton University, 2500 California Plaza, Omaha, NE 68178
| | - Michael G. Nichols
- Department of Physics, Creighton University, 2500 California Plaza, Omaha, NE 68178
- Corresponding Author: Phone: 402.280.2159; FAX: 402.280.2140;
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Li DDU, Ameer-Beg S, Arlt J, Tyndall D, Walker R, Matthews DR, Visitkul V, Richardson J, Henderson RK. Time-domain fluorescence lifetime imaging techniques suitable for solid-state imaging sensor arrays. SENSORS 2012; 12:5650-69. [PMID: 22778606 PMCID: PMC3386705 DOI: 10.3390/s120505650] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 04/18/2012] [Accepted: 04/26/2012] [Indexed: 11/27/2022]
Abstract
We have successfully demonstrated video-rate CMOS single-photon avalanche diode (SPAD)-based cameras for fluorescence lifetime imaging microscopy (FLIM) by applying innovative FLIM algorithms. We also review and compare several time-domain techniques and solid-state FLIM systems, and adapt the proposed algorithms for massive CMOS SPAD-based arrays and hardware implementations. The theoretical error equations are derived and their performances are demonstrated on the data obtained from 0.13 μm CMOS SPAD arrays and the multiple-decay data obtained from scanning PMT systems. In vivo two photon fluorescence lifetime imaging data of FITC-albumin labeled vasculature of a P22 rat carcinosarcoma (BD9 rat window chamber) are used to test how different algorithms perform on bi-decay data. The proposed techniques are capable of producing lifetime images with enough contrast.
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Affiliation(s)
- David Day-Uei Li
- Department of Engineering and Design, School of Engineering and Informatics, University of Sussex, Brighton BN1 9QT, UK
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +44-127-387-3513
| | - Simon Ameer-Beg
- Division of Cancer Research & Randall Division of Cell and Molecular Biophysics, Richard Dimbleby Department of Cancer Research, Guy's Campus, London SE1 1UL, UK; E-Mails: (S.A.B.); (V.V.)
| | - Jochen Arlt
- SUPA, COSMIC, School of Physics and Astronomy, The University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh EH9 3JZ, Scotland, UK; E-Mail:
| | - David Tyndall
- Institute for Integrated Micro and Nano Systems, The School of Engineering, The University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh EH9 3JL, Scotland, UK; E-Mails: (D.T.); (R.W.); (J.R.); (R.K.H.)
| | - Richard Walker
- Institute for Integrated Micro and Nano Systems, The School of Engineering, The University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh EH9 3JL, Scotland, UK; E-Mails: (D.T.); (R.W.); (J.R.); (R.K.H.)
| | - Daniel R. Matthews
- Queensland Brain Institute, University of Queensland, St. Lucia, QLD 4072, Australia; E-Mail:
| | - Viput Visitkul
- Division of Cancer Research & Randall Division of Cell and Molecular Biophysics, Richard Dimbleby Department of Cancer Research, Guy's Campus, London SE1 1UL, UK; E-Mails: (S.A.B.); (V.V.)
| | - Justin Richardson
- Institute for Integrated Micro and Nano Systems, The School of Engineering, The University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh EH9 3JL, Scotland, UK; E-Mails: (D.T.); (R.W.); (J.R.); (R.K.H.)
| | - Robert K. Henderson
- Institute for Integrated Micro and Nano Systems, The School of Engineering, The University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh EH9 3JL, Scotland, UK; E-Mails: (D.T.); (R.W.); (J.R.); (R.K.H.)
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50
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Laptenok SP, van Stokkum IHM, Borst JW, van Oort B, Visser AJWG, van Amerongen H. Disentangling Picosecond Events That Complicate the Quantitative Use of the Calcium Sensor YC3.60. J Phys Chem B 2012; 116:3013-20. [DOI: 10.1021/jp211830e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. P. Laptenok
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - I. H. M. van Stokkum
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | | | - B. van Oort
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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