1
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Luo J, Zhu Z. Sensitive and High-Throughput Time-Resolved Luminescence Detection of Tetracycline in Milk for Eliminating Background Fluorescence on a Miniaturized Apparatus. Anal Chem 2024. [PMID: 38949267 DOI: 10.1021/acs.analchem.4c01508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Fluorescence detection has always suffered from high background fluorescence from real samples such as milk. Therefore, cumbersome pretreatments of samples were necessary to remove the fluorescent substances but led to long processing times and low efficiency. Time-resolved luminescence detection is a powerful technique for eliminating short-lived background fluorescence without additional pretreatments. However, the related instruments are usually equipped with high-speed excitation sources and detectors, which are always bulky and expensive. Herein, we developed a low-cost and miniaturized imaging system for high-throughput time-gated luminescence detection. An UV LED array was used to excite multiple samples, the luminescence of which could be detected by a smartphone simultaneously. An analog circuit was designed to synchronize the LED to the mechanical chopper to eliminate the background signals resulting from scattering and short-lived autofluorescence. Compared to other synchronous circuits based on FPGAs and microcontrollers, this analog circuit required no programming and memory. For the first time, high-throughput time-resolved luminescence detection of tetracycline in milk without any separation or enrichment was achieved by utilizing a smartphone as a camera, and the scattered signals and the background fluorescence were eliminated efficiently. The limit of detection reached as low as 53 nM (∼0.024 ppm), lower than the residue limit set by the European Union. This high-throughput time-gated luminescence detection method can be used for quantitative analysis of many real samples with high background fluorescence.
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Affiliation(s)
- Jiahui Luo
- Department of Chemistry and Chemical Engineering, School of Bioengineering and Health, State Key Laboratory of New Textile Materials and Advanced Processing Technologies, Wuhan Textile University, Wuhan 430200, China
| | - Zece Zhu
- Department of Chemistry and Chemical Engineering, School of Bioengineering and Health, State Key Laboratory of New Textile Materials and Advanced Processing Technologies, Wuhan Textile University, Wuhan 430200, China
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2
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Deng Q, Liu Y, Zhu Z, Shu X. Microsecond-resolved smartphone time-gated luminescence spectroscopy. OPTICS LETTERS 2022; 47:3427-3430. [PMID: 35838696 DOI: 10.1364/ol.467458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 06/12/2022] [Indexed: 06/15/2023]
Abstract
Time-gated luminescence spectra are usually measured by laboratory instruments equipped with high-speed excitation sources and spectrometers, which are always bulky and expensive. To reduce the reliance on expensive laboratory instruments, we demonstrate the first, to the best of our knowledge, use of a smartphone for the detection of time-gated luminescence spectra. A mechanical chopper is used as the detection shutter and an optical switch is placed at the edge of the wheel to convert the chopping signal into a transistor-transistor logic (TTL) signal which is used to control the excitation source and achieve synchronization. The time-gated luminescence spectra at different delay times of Eu(TTA)3 powder and the solutions of Eu-tetracycline complex are successfully detected with a temporal resolution of tens of microseconds by the proposed approach. We believe our approach offers a route toward portable instruments for the measurement of luminescence spectra and lifetimes.
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3
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Zhu Z, Sun Y, Ma T, Tian D, Zhu J. Luminescence lifetime imaging of ultra-long room temperature phosphorescence on a smartphone. Anal Bioanal Chem 2021; 413:3291-3297. [PMID: 33772340 DOI: 10.1007/s00216-021-03266-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/04/2021] [Accepted: 03/02/2021] [Indexed: 11/27/2022]
Abstract
Luminescence lifetime imaging plays an important role in distinguishing the luminescence decay rates in time-resolved luminescence imaging. However, traditional imaging instruments used for detecting lifetimes within milliseconds would be time-consuming when imaging ultra-long luminescence lifetimes over subseconds. Herein, we present an accessible and simple optical system for detecting lifetimes of persistent luminescence. A smartphone integrated with a UV LED, a dichroic mirror, and a lens was used for recording the persistent luminescence. With only a few seconds of data acquisition, a luminescence lifetime image could be processed from the video by exponential fitting of the gray level of each pixel to the delay time. Since this approach only requires single excitation, no synchronous control is needed, greatly simplifying the apparatus and saving the cost. The apparatus was successfully used for ultra-long luminescence lifetime imaging of mouse tissue dyed with a persistent luminescence molecule. This miniaturized apparatus exhibits huge potentiality in time-resolved luminescence imaging for luminescence study and biological detection.
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Affiliation(s)
- Zece Zhu
- Wuhan National Lab for Optoelectronics and Key Lab of Materials Chemistry for Energy Conversion and Storage of Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Ye Sun
- Wuhan National Lab for Optoelectronics and Key Lab of Materials Chemistry for Energy Conversion and Storage of Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Teng Ma
- Wuhan National Lab for Optoelectronics and Key Lab of Materials Chemistry for Energy Conversion and Storage of Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Di Tian
- Wuhan National Lab for Optoelectronics and Key Lab of Materials Chemistry for Energy Conversion and Storage of Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China.
- Hubei Key Lab of Biomass Fibers and Eco-dyeing & Finishing, Department of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan, 430073, Hubei, China.
| | - Jintao Zhu
- Wuhan National Lab for Optoelectronics and Key Lab of Materials Chemistry for Energy Conversion and Storage of Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China.
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4
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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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5
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Deng Q, Zhu Z, Shu X. Spectrally resolved luminescence lifetime detection for measuring the energy splitting of the long-lived excited states. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 224:117434. [PMID: 31394392 DOI: 10.1016/j.saa.2019.117434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 06/10/2023]
Abstract
Molecular motion plays an important role in the reverse intersystem crossing of thermally activated delayed fluorescence (TADF) materials, since the conformation varies as the molecule vibrates, leading to potential changes in the energies of excited states. Although many theoretical simulations have researched the relationship between the excited states and the molecular conformations, there are still few experimental results showing the energy level difference between different long-lived excited states. Herein, a novel method for measuring spectrally resolved luminescence lifetimes is proposed to detect the energy splitting of the long-lived excited states of a classical TADF molecule, BTZ-DMAC. A set of the time-gated luminescence spectra with different delay times were captured by a spectrograph equipped on an auto-phase-locked system, and then used for lifetime analysis at each wavelength. Unlike traditional measurement techniques, the proposed novel method does not require ultrafast laser, high-speed detector and any phase matching circuitry, thus significantly reducing the cost. This method revealed a definite energy gap between the two excited states of BTZ-DMAC with different lifetimes, indicating different conformations caused by molecular vibration. This low-cost method could be also used to detect many other luminescence materials for investigating the detail mechanisms of multiple excited states.
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Affiliation(s)
- Qisheng Deng
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zece Zhu
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Xuewen Shu
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China.
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6
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Chen H, Ma N, Kagawa K, Kawahito S, Digman M, Gratton E. Widefield multifrequency fluorescence lifetime imaging using a two-tap complementary metal-oxide semiconductor camera with lateral electric field charge modulators. JOURNAL OF BIOPHOTONICS 2019; 12:e201800223. [PMID: 30421535 DOI: 10.1002/jbio.201800223] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Revised: 10/30/2018] [Accepted: 11/09/2018] [Indexed: 06/09/2023]
Abstract
Widefield frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM) measures the fluorescence lifetime of entire images in a fast and efficient manner. We report a widefield FD-FLIM system based on a complementary metal-oxide semiconductor camera equipped with two-tap true correlated double sampling lock-in pixels and lateral electric field charge modulators. Owing to the fast intrinsic response and modulation of the camera, our system allows parallel multifrequency FLIM in one measurement via fast Fourier transform. We demonstrate that at a fundamental frequency of 20 MHz, 31-harmonics can be measured with 64 phase images per laser repetition period. As a proof of principle, we analyzed cells transfected with Cerulean and with a construct of Cerulean-Venus that shows Förster Resonance Energy Transfer at different modulation frequencies. We also tracked the temperature change of living cells via the fluorescence lifetime of Rhodamine B at different frequencies. These results indicate that our widefield multifrequency FD-FLIM system is a valuable tool in the biomedical field.
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Affiliation(s)
- Hongtao Chen
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
| | - Ning Ma
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
| | - Keiichiro Kagawa
- Research Institute of Electronics, Shizuoka University, Hamamatsu, Shizuoka, Japan
| | - Shoji Kawahito
- Research Institute of Electronics, Shizuoka University, Hamamatsu, Shizuoka, Japan
| | - Michelle Digman
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California
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7
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Ströhl F, Kaminski CF. A concept for single-shot volumetric fluorescence imaging via orthogonally polarized excitation lattices. Sci Rep 2019; 9:6425. [PMID: 31015487 PMCID: PMC6478832 DOI: 10.1038/s41598-019-42743-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 04/08/2019] [Indexed: 11/08/2022] Open
Abstract
The deconvolution of widefield fluorescence images provides only guesses of spatial frequency information along the optical axis due to the so called missing cone in the optical transfer function. Retaining the single-shot imaging speed of deconvolution microscopy while gaining access to missing cone information is thus highly desirable for microscopy of volumetric samples. Here, we present a concept that superimposes two orthogonally polarized excitation lattices with a phase-shift of p between them. In conjunction with a non-iterative image reconstruction algorithm this permits the restoration of missing cone information. We show how fluorescence anisotropy could be used as a method to encode and decode the patterns simultaneously and develop a rigorous theoretical framework for the method. Through in-silico experiments and imaging of fixed biological cells on a structured illumination microscope that emulates the proposed setup we validate the feasibility of the method.
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Affiliation(s)
- Florian Ströhl
- Department of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS, Cambridge, UK.
- Department of Physics and Technology, UiT-The Arctic University of Norway, 9037, Tromsø, Norway.
| | - Clemens F Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS, Cambridge, UK.
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8
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Chen W, Avezov E, Schlachter SC, Gielen F, Laine RF, Harding HP, Hollfelder F, Ron D, Kaminski CF. A method to quantify FRET stoichiometry with phasor plot analysis and acceptor lifetime ingrowth. Biophys J 2016; 108:999-1002. [PMID: 25762312 PMCID: PMC4375440 DOI: 10.1016/j.bpj.2015.01.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/23/2014] [Accepted: 01/09/2015] [Indexed: 11/26/2022] Open
Abstract
FRET is widely used for the study of protein-protein interactions in biological samples. However, it is difficult to quantify both the FRET efficiency (E) and the affinity (Kd) of the molecular interaction from intermolecular FRET signals in samples of unknown stoichiometry. Here, we present a method for the simultaneous quantification of the complete set of interaction parameters, including fractions of bound donors and acceptors, local protein concentrations, and dissociation constants, in each image pixel. The method makes use of fluorescence lifetime information from both donor and acceptor molecules and takes advantage of the linear properties of the phasor plot approach. We demonstrate the capability of our method in vitro in a microfluidic device and also in cells, via the determination of the binding affinity between tagged versions of glutathione and glutathione S-transferase, and via the determination of competitor concentration. The potential of the method is explored with simulations.
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Affiliation(s)
- WeiYue Chen
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
| | - Edward Avezov
- The Wellcome Trust Medical Research Council Institute of Metabolic Science and National Institute for Health Research, Cambridge Biomedical Research Centre, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Simon C Schlachter
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
| | - Fabrice Gielen
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Romain F Laine
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom
| | - Heather P Harding
- The Wellcome Trust Medical Research Council Institute of Metabolic Science and National Institute for Health Research, Cambridge Biomedical Research Centre, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - David Ron
- The Wellcome Trust Medical Research Council Institute of Metabolic Science and National Institute for Health Research, Cambridge Biomedical Research Centre, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Clemens F Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, United Kingdom.
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9
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Chen H, Holst G, Gratton E. Modulated CMOS camera for fluorescence lifetime microscopy. Microsc Res Tech 2015; 78:1075-81. [PMID: 26500051 DOI: 10.1002/jemt.22587] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 09/21/2015] [Indexed: 11/11/2022]
Abstract
Widefield frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM) is a fast and accurate method to measure the fluorescence lifetime of entire images. However, the complexity and high costs involved in construction of such a system limit the extensive use of this technique. PCO AG recently released the first luminescence lifetime imaging camera based on a high frequency modulated CMOS image sensor, QMFLIM2. Here we tested and provide operational procedures to calibrate the camera and to improve the accuracy using corrections necessary for image analysis. With its flexible input/output options, we are able to use a modulated laser diode or a 20 MHz pulsed white supercontinuum laser as the light source. The output of the camera consists of a stack of modulated images that can be analyzed by the SimFCS software using the phasor approach. The nonuniform system response across the image sensor must be calibrated at the pixel level. This pixel calibration is crucial and needed for every camera settings, e.g. modulation frequency and exposure time. A significant dependency of the modulation signal on the intensity was also observed and hence an additional calibration is needed for each pixel depending on the pixel intensity level. These corrections are important not only for the fundamental frequency, but also for the higher harmonics when using the pulsed supercontinuum laser. With these post data acquisition corrections, the PCO CMOS-FLIM camera can be used for various biomedical applications requiring a large frame and high speed acquisition.
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Affiliation(s)
- Hongtao Chen
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering University of California, Irvine, California
| | | | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering University of California, Irvine, California
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10
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Zhao M, Li Y, Peng L. FPGA-based multi-channel fluorescence lifetime analysis of Fourier multiplexed frequency-sweeping lifetime imaging. OPTICS EXPRESS 2014; 22:23073-85. [PMID: 25321778 PMCID: PMC4247184 DOI: 10.1364/oe.22.023073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/26/2014] [Accepted: 08/27/2014] [Indexed: 05/02/2023]
Abstract
We report a fast non-iterative lifetime data analysis method for the Fourier multiplexed frequency-sweeping confocal FLIM (Fm-FLIM) system [Opt. Express 22, 10221 (2014)]. The new method, named R-method, allows fast multi-channel lifetime image analysis in the system's FPGA data processing board. Experimental tests proved that the performance of the R-method is equivalent to that of single-exponential iterative fitting, and its sensitivity is well suited for time-lapse FLIM-FRET imaging of live cells, for example cyclic adenosine monophosphate (cAMP) level imaging with GFP-Epac-mCherry sensors. With the R-method and its FPGA implementation, multi-channel lifetime images can now be generated in real time on the multi-channel frequency-sweeping FLIM system, and live readout of FRET sensors can be performed during time-lapse imaging.
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Affiliation(s)
- Ming Zhao
- College of Optical Sciences, the University of Arizona, 1630 East University Blvd., Tucson, AZ 85721,
USA
| | - Yu Li
- College of Optical Sciences, the University of Arizona, 1630 East University Blvd., Tucson, AZ 85721,
USA
| | - Leilei Peng
- College of Optical Sciences, the University of Arizona, 1630 East University Blvd., Tucson, AZ 85721,
USA
- Molecular and Cellular Biology, the University of Arizona, 1007 E. Lowell St., Tucson, AZ 85721,
USA
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11
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Fereidouni F, Blab GA, Gerritsen HC. Phasor based analysis of FRET images recorded using spectrally resolved lifetime imaging. Methods Appl Fluoresc 2014; 2:035001. [DOI: 10.1088/2050-6120/2/3/035001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Tudor C, te Riet J, Eich C, Harkes R, Smisdom N, Bouhuijzen Wenger J, Ameloot M, Holt M, Kanger JS, Figdor CG, Cambi A, Subramaniam V. Syntenin-1 and ezrin proteins link activated leukocyte cell adhesion molecule to the actin cytoskeleton. J Biol Chem 2014; 289:13445-60. [PMID: 24662291 DOI: 10.1074/jbc.m113.546754] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activated leukocyte cell adhesion molecule (ALCAM) is a type I transmembrane protein member of the immunoglobulin superfamily of cell adhesion molecules. Involved in important pathophysiological processes such as the immune response, cancer metastasis, and neuronal development, ALCAM undergoes both homotypic interactions with other ALCAM molecules and heterotypic interactions with the surface receptor CD6 expressed at the T cell surface. Despite biochemical and biophysical evidence of a dynamic association between ALCAM and the actin cytoskeleton, no detailed information is available about how this association occurs at the molecular level. Here, we exploit a combination of complementary microscopy techniques, including FRET detected by fluorescence lifetime imaging microscopy and single-cell force spectroscopy, and we demonstrate the existence of a preformed ligand-independent supramolecular complex where ALCAM stably interacts with actin by binding to syntenin-1 and ezrin. Interaction with the ligand CD6 further enhances these multiple interactions. Altogether, our results propose a novel biophysical framework to understand the stabilizing role of the ALCAM supramolecular complex engaged to CD6 during dendritic cell-T cell interactions and provide novel information on the molecular players involved in the formation and signaling of the immunological synapse at the dendritic cell side.
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Affiliation(s)
- Cicerone Tudor
- From the Nanobiophysics, MIRA Institute for Biomedical Technology and Technical Medicine and MESA+ Institute for Nanotechnology, University of Twente, 7500AE Enschede, The Netherlands
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13
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Chen H, Gratton E. A practical implementation of multifrequency widefield frequency-domain fluorescence lifetime imaging microscopy. Microsc Res Tech 2013; 76:282-9. [PMID: 23296945 DOI: 10.1002/jemt.22165] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 11/26/2012] [Indexed: 11/10/2022]
Abstract
Widefield frequency-domain fluorescence lifetime imaging microscopy (FD-FLIM) is a fast and accurate method to measure the fluorescence lifetime, especially in kinetic studies in biomedical researches. However, the small range of modulation frequencies available in commercial instruments makes this technique limited in its applications. Herein, we describe a practical implementation of multifrequency widefield FD-FLIM using a pulsed supercontinuum laser and a direct digital synthesizer. In this instrument we use a pulse to modulate the image intensifier rather than the more conventional sine-wave modulation. This allows parallel multifrequency FLIM measurement using the Fast Fourier Transform and the cross-correlation technique, which permits precise and simultaneous isolation of individual frequencies. In addition, the pulse modulation at the cathode of image intensifier restores the loss of optical resolution caused by the defocusing effect when the cathode is sinusoidally modulated. Furthermore, in our implementation of this technique, data can be graphically analyzed by the phasor method while data are acquired, which allows easy fit-free lifetime analysis of FLIM images. Here, our measurements of standard fluorescent samples and a Föster resonance energy transfer pair demonstrate that the widefield multifrequency FLIM system is a valuable and simple tool in fluorescence imaging studies.
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Affiliation(s)
- Hongtao Chen
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine, California, USA
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14
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Gibbs PEM, Tudor C, Maines MD. Biliverdin reductase: more than a namesake - the reductase, its Peptide fragments, and biliverdin regulate activity of the three classes of protein kinase C. Front Pharmacol 2012; 3:31. [PMID: 22419908 PMCID: PMC3299957 DOI: 10.3389/fphar.2012.00031] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Accepted: 02/16/2012] [Indexed: 01/04/2023] Open
Abstract
The expanse of human biliverdin reductase (hBVR) functions in the cells is arguably unmatched by any single protein. hBVR is a Ser/Thr/Tyr-kinase, a scaffold protein, a transcription factor, and an intracellular transporter of gene regulators. hBVR is an upstream activator of the insulin/IGF-1 signaling pathway and of protein kinase C (PKC) kinases in the two major arms of the pathway. In addition, it is the sole means for generating the antioxidant bilirubin-IXα. hBVR is essential for activation of ERK1/2 kinases by upstream MAPKK-MEK and by PKCδ, as well as the nuclear import and export of ERK1/2. Small fragments of hBVR are potent activators and inhibitors of the ERK kinases and PKCs: as such, they suggest the potential application of BVR-based technology in therapeutic settings. Presently, we have reviewed the function of hBVR in cell signaling with an emphasis on regulation of PKCδ activity.
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Affiliation(s)
- Peter E M Gibbs
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry Rochester, NY, USA
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15
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16
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Colyer RA, Siegmund OHW, Tremsin AS, Vallerga JV, Weiss S, Michalet X. Phasor imaging with a widefield photon-counting detector. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:016008. [PMID: 22352658 PMCID: PMC3380817 DOI: 10.1117/1.jbo.17.1.016008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 11/06/2011] [Accepted: 11/15/2011] [Indexed: 05/18/2023]
Abstract
Fluorescence lifetime can be used as a contrast mechanism to distinguish fluorophores for localization or tracking, for studying molecular interactions, binding, assembly, and aggregation, or for observing conformational changes via Förster resonance energy transfer (FRET) between donor and acceptor molecules. Fluorescence lifetime imaging microscopy (FLIM) is thus a powerful technique but its widespread use has been hampered by demanding hardware and software requirements. FLIM data is often analyzed in terms of multicomponent fluorescence lifetime decays, which requires large signals for a good signal-to-noise ratio. This confines the approach to very low frame rates and limits the number of frames which can be acquired before bleaching the sample. Recently, a computationally efficient and intuitive graphical representation, the phasor approach, has been proposed as an alternative method for FLIM data analysis at the ensemble and single-molecule level. In this article, we illustrate the advantages of combining phasor analysis with a widefield time-resolved single photon-counting detector (the H33D detector) for FLIM applications. In particular we show that phasor analysis allows real-time subsecond identification of species by their lifetimes and rapid representation of their spatial distribution, thanks to the parallel acquisition of FLIM information over a wide field of view by the H33D detector. We also discuss possible improvements of the H33D detector's performance made possible by the simplicity of phasor analysis and its relaxed timing accuracy requirements compared to standard time-correlated single-photon counting (TCSPC) methods.
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Affiliation(s)
- Ryan A. Colyer
- UCLA, Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, Los Angeles, California
| | | | - Anton S. Tremsin
- Space Sciences Laboratory, UCB, 7 Gauss Way, Berkeley, California
| | - John V. Vallerga
- Space Sciences Laboratory, UCB, 7 Gauss Way, Berkeley, California
| | - Shimon Weiss
- UCLA, Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, Los Angeles, California
| | - Xavier Michalet
- UCLA, Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, Los Angeles, California
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17
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Pereira AM, Tudor C, Kanger JS, Subramaniam V, Martin-Blanco E. Integrin-dependent activation of the JNK signaling pathway by mechanical stress. PLoS One 2011; 6:e26182. [PMID: 22180774 PMCID: PMC3236745 DOI: 10.1371/journal.pone.0026182] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 09/21/2011] [Indexed: 02/07/2023] Open
Abstract
Mechanical force is known to modulate the activity of the Jun N-terminal kinase (JNK) signaling cascade. However, the effect of mechanical stresses on JNK signaling activation has previously only been analyzed by in vitro detection methods. It still remains unknown how living cells activate the JNK signaling cascade in response to mechanical stress and what its functions are in stretched cells. We assessed in real-time the activity of the JNK pathway in Drosophila cells by Fluorescence Lifetime Imaging Microscopy (FLIM), using an intramolecular phosphorylation-dependent dJun-FRET (Fluorescence Resonance Energy Transfer) biosensor. We found that quantitative FRET-FLIM analysis and confocal microscopy revealed sustained dJun-FRET biosensor activation and stable morphology changes in response to mechanical stretch for Drosophila S2R+ cells. Further, these cells plated on different substrates showed distinct levels of JNK activity that associate with differences in cell morphology, integrin expression and focal adhesion organization. These data imply that alterations in the cytoskeleton and matrix attachments may act as regulators of JNK signaling, and that JNK activity might feed back to modulate the cytoskeleton and cell adhesion. We found that this dynamic system is highly plastic; at rest, integrins at focal adhesions and talin are key factors suppressing JNK activity, while multidirectional static stretch leads to integrin-dependent, and probably talin-independent, Jun sensor activation. Further, our data suggest that JNK activity has to coordinate with other signaling elements for the regulation of the cytoskeleton and cell shape remodeling associated with stretch.
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Affiliation(s)
- Andrea Maria Pereira
- Instituto de Biología Molecular de Barcelona (CSIC), Parc Cientific de Barcelona, Barcelona, Spain
| | - Cicerone Tudor
- Nanobiophysics, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Johannes S. Kanger
- Nanobiophysics, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Vinod Subramaniam
- Nanobiophysics, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
- * E-mail: (EMB); (VS)
| | - Enrique Martin-Blanco
- Instituto de Biología Molecular de Barcelona (CSIC), Parc Cientific de Barcelona, Barcelona, Spain
- * E-mail: (EMB); (VS)
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18
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Gibbs PEM, Miralem T, Lerner-Marmarosh N, Tudor C, Maines MD. Formation of ternary complex of human biliverdin reductase-protein kinase Cδ-ERK2 protein is essential for ERK2-mediated activation of Elk1 protein, nuclear factor-κB, and inducible nitric-oxidase synthase (iNOS). J Biol Chem 2011; 287:1066-79. [PMID: 22065579 DOI: 10.1074/jbc.m111.279612] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Growth factors, insulin, oxidative stress, and cytokines activate ERK1/2 by PKCδ and MEK1/2. Human biliverdin reductase (hBVR), a Ser/Thr/Tyr kinase and intracellular scaffold/bridge/anchor, is a nuclear transporter of MEK1/2-stimulated ERK1/2 (Lerner-Marmarosh, N., Miralem, T., Gibbs, P. E., and Maines, M. D. (2008) Proc. Natl. Acad. Sci. U.S.A. 105, 6870-6875). hBVR, PKCδ, and MEK1/2 overlap in their tissue expression profile and type of activators. Presently, we report on formation of an hBVR-PKCδ-ERK2 ternary complex that is essential for ERK2 signal transduction and activation of genes linked to cell proliferation and cancer. MEK1/2 and the protein phosphatase PP2A were also present in the complex. When cells were stimulated with insulin-like growth factor-1 (IGF-1), an increased interaction between hBVR and PKCδ was detected by FRET-fluorescence lifetime imaging microscopy. hBVR and ERK2 were phosphorylated by PKCδ; however, the PKC was not a substrate for either ERK2 or hBVR. IGF-1 and phorbol ester increased hBVR/PKCδ binding; hBVR was required for the activation of PKCδ and its interaction with ERK2. The C-terminal phenylalanine residues of PKCδ (Phe(660), Phe(663), and Phe(665)) were necessary for binding to ERK2 but not for hBVR binding. Formation of the hBVR-PKCδ-ERK2 complex required the hBVR docking site for ERK, FXFP (DEF, C-box) and D(δ)-box (ILXXLXL) motifs. The hBVR-based peptide KKRILHCLGLA inhibited PKC activation and PKCδ/ERK2 interaction. Phorbol ester- and TNF-α-dependent activation of the ERK-regulated transcription factors Elk1 and NF-κB and expression of the iNOS gene were suppressed by hBVR siRNA; those activities were rescued by hBVR. The findings reveal the direct input of hBVR in PKCδ/ERK signaling and identify hBVR-based peptide regulators of ERK-mediated gene activation.
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Affiliation(s)
- Peter E M Gibbs
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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19
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Esposito A, Bader AN, Schlachter SC, van den Heuvel DJ, Schierle GSK, Venkitaraman AR, Kaminski CF, Gerritsen HC. Design and application of a confocal microscope for spectrally resolved anisotropy imaging. OPTICS EXPRESS 2011; 19:2546-2555. [PMID: 21369074 DOI: 10.1364/oe.19.002546] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Biophysical imaging tools exploit several properties of fluorescence to map cellular biochemistry. However, the engineering of a cost-effective and user-friendly detection system for sensing the diverse properties of fluorescence is a difficult challenge. Here, we present a novel architecture for a spectrograph that permits integrated characterization of excitation, emission and fluorescence anisotropy spectra in a quantitative and efficient manner. This sensing platform achieves excellent versatility of use at comparatively low costs. We demonstrate the novel optical design with example images of plant cells and of mammalian cells expressing fluorescent proteins undergoing energy transfer.
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Affiliation(s)
- Alessandro Esposito
- The Medical Research Council Cancer Cell Unit, Hutchison/MRC Research Centre, Hills Road, Cambridge CB2 0XZ, UK.
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20
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Stöckl M, Herrmann A. Detection of lipid domains in model and cell membranes by fluorescence lifetime imaging microscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1444-56. [DOI: 10.1016/j.bbamem.2009.12.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 11/30/2009] [Accepted: 12/21/2009] [Indexed: 01/17/2023]
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21
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Affiliation(s)
- Mikhail Y. Berezin
- Department of Radiology, Washington University School of Medicine, 4525 Scott Ave, St. Louis, USA, Tel. 314-747-0701, 314-362-8599, fax 314-747-5191
| | - Samuel Achilefu
- Department of Radiology, Washington University School of Medicine, 4525 Scott Ave, St. Louis, USA, Tel. 314-747-0701, 314-362-8599, fax 314-747-5191
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22
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Elder AD, Kaminski CF, Frank JH. phi2FLIM: a technique for alias-free frequency domain fluorescence lifetime imaging. OPTICS EXPRESS 2009; 17:23181-23203. [PMID: 20052246 DOI: 10.1364/oe.17.023181] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A new approach to alias-free wide-field fluorescence lifetime imaging in the frequency domain is demonstrated using a supercontinuum source for fluorescence excitation and a phase-modulated image intensifier for detection. This technique is referred to as phi-squared fluorescence lifetime imaging (phi(2)FLIM). The phase modulation and square-wave gating of the image intensifier eliminate aliasing by the effective suppression of higher harmonics. The ability to use picosecond excitation pulses without aliasing expands the range of excitation sources available for frequency-domain fluorescence lifetime imaging (fd-FLIM) and improves the modulation depth of conventional homodyne fd-FLIM measurements, which use sinusoidal intensity modulation of the excitation source. The phi(2)FLIM results are analyzed using AB-plots, which facilitate the identification of mono-exponential and multi-exponential fluorescence decays and provide measurements of the fluorophore fractions in two component mixtures. The rapid acquisition speed of the technique enables lifetime measurements in dynamic systems, such as temporally evolving samples and samples that are sensitive to photo-bleaching. Rapid phi(2)FLIM measurements are demonstrated by imaging the dynamic mixing of two different dye solutions at 5.5 Hz. The tunability of supercontinuum radiation enables excitation wavelength resolved FLIM measurements, which facilitates analysis of samples containing multiple fluorophores with different absorption spectra.
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Affiliation(s)
- Alan D Elder
- Department of Chemical Engineering, University of Cambridge, Cambridge, CB2 3RA, UK
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23
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Schlachter S, Schwedler S, Esposito A, Kaminski Schierle GS, Moggridge GD, Kaminski CF. A method to unmix multiple fluorophores in microscopy images with minimal a priori information. OPTICS EXPRESS 2009; 17:22747-22760. [PMID: 20052200 DOI: 10.1364/oe.17.022747] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The ability to quantify the fluorescence signals from multiply labeled biological samples is highly desirable in the life sciences but often difficult, because of spectral overlap between fluorescent species and the presence of autofluorescence. Several so called unmixing algorithms have been developed to address this problem. Here, we present a novel algorithm that combines measurements of lifetime and spectrum to achieve unmixing without a priori information on the spectral properties of the fluorophore labels. The only assumption made is that the lifetimes of the fluorophores differ. Our method combines global analysis for a measurement of lifetime distributions with singular value decomposition to recover individual fluorescence spectra. We demonstrate the technique on simulated datasets and subsequently by an experiment on a biological sample. The method is computationally efficient and straightforward to implement. Applications range from histopathology of complex and multiply labelled samples to functional imaging in live cells.
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Affiliation(s)
- S Schlachter
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke St, Cambridge, CB2 1RA, U.K
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24
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Kelleher MT, Fruhwirth G, Patel G, Ofo E, Festy F, Barber PR, Ameer-Beg SM, Vojnovic B, Gillett C, Coolen A, Kéri G, Ellis PA, Ng T. The potential of optical proteomic technologies to individualize prognosis and guide rational treatment for cancer patients. Target Oncol 2009; 4:235-52. [PMID: 19756916 PMCID: PMC2778706 DOI: 10.1007/s11523-009-0116-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Accepted: 08/28/2009] [Indexed: 12/21/2022]
Abstract
Genomics and proteomics will improve outcome prediction in cancer and have great potential to help in the discovery of unknown mechanisms of metastasis, ripe for therapeutic exploitation. Current methods of prognosis estimation rely on clinical data, anatomical staging and histopathological features. It is hoped that translational genomic and proteomic research will discriminate more accurately than is possible at present between patients with a good prognosis and those who carry a high risk of recurrence. Rational treatments, targeted to the specific molecular pathways of an individual's high-risk tumor, are at the core of tailored therapy. The aim of targeted oncology is to select the right patient for the right drug at precisely the right point in their cancer journey. Optical proteomics uses advanced optical imaging technologies to quantify the activity states of and associations between signaling proteins by measuring energy transfer between fluorophores attached to specific proteins. Förster resonance energy transfer (FRET) and fluorescence lifetime imaging microscopy (FLIM) assays are suitable for use in cell line models of cancer, fresh human tissues and formalin-fixed paraffin-embedded tissue (FFPE). In animal models, dynamic deep tissue FLIM/FRET imaging of cancer cells in vivo is now also feasible. Analysis of protein expression and post-translational modifications such as phosphorylation and ubiquitination can be performed in cell lines and are remarkably efficiently in cancer tissue samples using tissue microarrays (TMAs). FRET assays can be performed to quantify protein-protein interactions within FFPE tissue, far beyond the spatial resolution conventionally associated with light or confocal laser microscopy. Multivariate optical parameters can be correlated with disease relapse for individual patients. FRET-FLIM assays allow rapid screening of target modifiers using high content drug screens. Specific protein-protein interactions conferring a poor prognosis identified by high content tissue screening will be perturbed with targeted therapeutics. Future targeted drugs will be identified using high content/throughput drug screens that are based on multivariate proteomic assays. Response to therapy at a molecular level can be monitored using these assays while the patient receives treatment: utilizing re-biopsy tumor tissue samples in the neoadjuvant setting or by examining surrogate tissues. These technologies will prove to be both prognostic of risk for individuals when applied to tumor tissue at first diagnosis and predictive of response to specifically selected targeted anticancer drugs. Advanced optical assays have great potential to be translated into real-life benefit for cancer patients.
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Affiliation(s)
- Muireann T. Kelleher
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, 2nd Floor, New Hunt House, Guy’s Medical School Campus, London, SE1 1UL UK
- Department Medical Oncology, Guy’s Hospital, London, SE1 9RT UK
| | - Gilbert Fruhwirth
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, 2nd Floor, New Hunt House, Guy’s Medical School Campus, London, SE1 1UL UK
| | - Gargi Patel
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, 2nd Floor, New Hunt House, Guy’s Medical School Campus, London, SE1 1UL UK
| | - Enyinnaya Ofo
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, 2nd Floor, New Hunt House, Guy’s Medical School Campus, London, SE1 1UL UK
| | - Frederic Festy
- Biomaterial, Biomimetics & Biophotonics Research Group, King’s College London, London, UK
| | - Paul R. Barber
- Gray Institute for Radiation Oncology & Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ UK
| | - Simon M. Ameer-Beg
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, 2nd Floor, New Hunt House, Guy’s Medical School Campus, London, SE1 1UL UK
| | - Borivoj Vojnovic
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, 2nd Floor, New Hunt House, Guy’s Medical School Campus, London, SE1 1UL UK
- Gray Institute for Radiation Oncology & Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ UK
| | - Cheryl Gillett
- Guy’s & St Thomas’ Breast Tissue & Data Bank, King’s College London, Guy’s Hospital, London, SE1 9RT UK
| | - Anthony Coolen
- Department of Mathematics, King’s College London, Strand Campus, London, WC2R 2LS UK
| | - György Kéri
- Vichem Chemie Research Ltd., Herman Ottó utca 15, Budapest, Hungary
- Pathobiochemistry Research Group of Hungarian Academy of Science, Semmelweis University, Budapest, 1444 Bp 8. POB 260, Hungary
| | - Paul A. Ellis
- Department Medical Oncology, Guy’s Hospital, London, SE1 9RT UK
| | - Tony Ng
- Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, Kings College London, 2nd Floor, New Hunt House, Guy’s Medical School Campus, London, SE1 1UL UK
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