1
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Michalet X. Continuous and discrete phasor analysis of binned or time-gated periodic decays. AIP ADVANCES 2021; 11:035331. [PMID: 33786208 PMCID: PMC7990508 DOI: 10.1063/5.0027834] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 01/22/2021] [Indexed: 05/29/2023]
Abstract
The time-resolved analysis of periodically excited luminescence decays by the phasor method in the presence of time-gating or binning is revisited. Analytical expressions for discrete configurations of square gates are derived, and the locus of the phasors of such modified periodic single-exponential decays is compared to the canonical universal semicircle. The effects of instrument response function offset, decay truncation, and gate shape are also discussed. Finally, modified expressions for the phase and modulus lifetimes are provided for some simple cases. A discussion of a modified phasor calibration approach is presented, and an illustration of the new concepts with examples from the literature concludes this work.
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Affiliation(s)
- Xavier Michalet
- Department of Chemistry and Biochemistry, 607 Charles E. Young Drive E., Los Angeles, California 90095, USA
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2
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Junek J, Žídek K. Fluorescence lifetime imaging via spatio-temporal speckle patterns in a single-pixel camera configuration. OPTICS EXPRESS 2021; 29:5538-5551. [PMID: 33726089 DOI: 10.1364/oe.413650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
Photoluminescence (PL) spectroscopy offers excellent methods for mapping the PL decay on the nanosecond time scale. However, capturing maps of emission dynamics on the microsecond timescale can be highly time-consuming. We present a new approach to fluorescence lifetime imaging (FLIM), which combines the concept of random temporal speckles excitation (RATS) with the concept of a single-pixel camera based on spatial speckles. The spatio-temporal speckle pattern makes it possible to map PL dynamics with unmatched simplicity. Moreover, the method can acquire all the data necessary to map PL decay on the microsecond timescale within minutes. We present proof-of-principle measurements for two samples and compare the reconstructed decays to the non-imaging measurements. Finally, we discuss the effect of the preprocessing routine and other factors on the reconstruction noise level. The presented method is suitable for lifetime imaging processes in several samples, including monitoring charge carrier dynamics in perovskites or monitoring solid-state luminophores with a long lifetime of PL.
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3
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The centenary of the Stern-Volmer equation of fluorescence quenching: From the single line plot to the SV quenching map. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2020. [DOI: 10.1016/j.jphotochemrev.2019.100338] [Citation(s) in RCA: 118] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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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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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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6
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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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7
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Sparks H, Görlitz F, Kelly DJ, Warren SC, Kellett PA, Garcia E, Dymoke-Bradshaw AKL, Hares JD, Neil MAA, Dunsby C, French PMW. Characterisation of new gated optical image intensifiers for fluorescence lifetime imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:013707. [PMID: 28147687 DOI: 10.1063/1.4973917] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report the characterisation of gated optical image intensifiers for fluorescence lifetime imaging, evaluating the performance of several different prototypes that culminate in a new design that provides improved spatial resolution conferred by the addition of a magnetic field to reduce the lateral spread of photoelectrons on their path between the photocathode and microchannel plate, and higher signal to noise ratio conferred by longer time gates. We also present a methodology to compare these systems and their capabilities, including the quantitative readouts of Förster resonant energy transfer.
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Affiliation(s)
- H Sparks
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW, United Kingdom
| | - F Görlitz
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW, United Kingdom
| | - D J Kelly
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW, United Kingdom
| | - S C Warren
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW, United Kingdom
| | - P A Kellett
- Kentech Instruments Ltd., Howbery Park, Wallingford OX10 8BD, United Kingdom
| | - E Garcia
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW, United Kingdom
| | | | - J D Hares
- Kentech Instruments Ltd., Howbery Park, Wallingford OX10 8BD, United Kingdom
| | - M A A Neil
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW, United Kingdom
| | - C Dunsby
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW, United Kingdom
| | - P M W French
- Photonics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2BW, United Kingdom
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8
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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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9
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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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10
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Chen WL, Hu PS, Ghazaryan A, Chen SJ, Tsai TH, Dong CY. Quantitative analysis of multiphoton excitation autofluorescence and second harmonic generation imaging for medical diagnosis. Comput Med Imaging Graph 2012; 36:519-26. [PMID: 22824186 DOI: 10.1016/j.compmedimag.2012.06.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 06/05/2012] [Accepted: 06/15/2012] [Indexed: 11/26/2022]
Abstract
In recent years, two-photon excitation fluorescence and second harmonic generation microscopy has become an important tool in biomedical research. The ability of two-photon microscopy to achieve optical sectioning with minimal invasiveness is particularly advantageous for biomedical diagnosis. Advances in the miniaturization of the imaging system have increased its clinical potential, together with the development of quantitative technique for the analysis of data acquired using these imaging modalities. We present a review of the quantitative analysis techniques that have been used successfully with two-photon excitation fluorescence and SHG imaging. Specifically, quantification techniques using ratiometric, morphological, and structural differences to analyze two-photon images will be discussed, and their effectiveness at evaluating dermal and corneal pathologies and cancerous tumor growth will be described.
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Affiliation(s)
- Wei-Liang Chen
- Department of Physics, National Taiwan University, Taipei, Taiwan.
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11
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Bui M, Dimitriadis EK, Hoischen C, An E, Quénet D, Giebe S, Nita-Lazar A, Diekmann S, Dalal Y. Cell-cycle-dependent structural transitions in the human CENP-A nucleosome in vivo. Cell 2012; 150:317-26. [PMID: 22817894 PMCID: PMC3592566 DOI: 10.1016/j.cell.2012.05.035] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 12/19/2011] [Accepted: 05/18/2012] [Indexed: 12/21/2022]
Abstract
In eukaryotes, DNA is packaged into chromatin by canonical histone proteins. The specialized histone H3 variant CENP-A provides an epigenetic and structural basis for chromosome segregation by replacing H3 at centromeres. Unlike exclusively octameric canonical H3 nucleosomes, CENP-A nucleosomes have been shown to exist as octamers, hexamers, and tetramers. An intriguing possibility reconciling these observations is that CENP-A nucleosomes cycle between octamers and tetramers in vivo. We tested this hypothesis by tracking CENP-A nucleosomal components, structure, chromatin folding, and covalent modifications across the human cell cycle. We report that CENP-A nucleosomes alter from tetramers to octamers before replication and revert to tetramers after replication. These structural transitions are accompanied by reversible chaperone binding, chromatin fiber folding changes, and previously undescribed modifications within the histone fold domains of CENP-A and H4. Our results reveal a cyclical nature to CENP-A nucleosome structure and have implications for the maintenance of epigenetic memory after centromere replication.
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Affiliation(s)
- Minh Bui
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Emilios K. Dimitriadis
- Laboratory of Biomedical Engineering and Physical Sciences, National Institute of Biomedical Imaging and Bioengineering, NIH, Bethesda, MD 20892, USA
| | | | - Eunkyung An
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Delphine Quénet
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | | | - Aleksandra Nita-Lazar
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | | | - Yamini Dalal
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
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12
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Kumar S, Alibhai D, Margineanu A, Laine R, Kennedy G, McGinty J, Warren S, Kelly D, Alexandrov Y, Munro I, Talbot C, Stuckey DW, Kimberly C, Viellerobe B, Lacombe F, Lam EWF, Taylor H, Dallman MJ, Stamp G, Murray EJ, Stuhmeier F, Sardini A, Katan M, Elson DS, Neil MAA, Dunsby C, French PMW. FLIM FRET technology for drug discovery: automated multiwell-plate high-content analysis, multiplexed readouts and application in situ. Chemphyschem 2011; 12:609-26. [PMID: 21337485 PMCID: PMC3084521 DOI: 10.1002/cphc.201000874] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 12/07/2010] [Indexed: 11/10/2022]
Abstract
A fluorescence lifetime imaging (FLIM) technology platform intended to read out changes in Förster resonance energy transfer (FRET) efficiency is presented for the study of protein interactions across the drug-discovery pipeline. FLIM provides a robust, inherently ratiometric imaging modality for drug discovery that could allow the same sensor constructs to be translated from automated cell-based assays through small transparent organisms such as zebrafish to mammals. To this end, an automated FLIM multiwell-plate reader is described for high content analysis of fixed and live cells, tomographic FLIM in zebrafish and FLIM FRET of live cells via confocal endomicroscopy. For cell-based assays, an exemplar application reading out protein aggregation using FLIM FRET is presented, and the potential for multiple simultaneous FLIM (FRET) readouts in microscopy is illustrated.
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Affiliation(s)
- Sunil Kumar
- Photonics Group, Department of Physics, Imperial College London, London SW7 2AZ, UK.
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13
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Mauritz JMA, Esposito A, Tiffert T, Skepper JN, Warley A, Yoon YZ, Cicuta P, Lew VL, Guck JR, Kaminski CF. Biophotonic techniques for the study of malaria-infected red blood cells. Med Biol Eng Comput 2010; 48:1055-63. [PMID: 20661776 DOI: 10.1007/s11517-010-0668-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 07/11/2010] [Indexed: 12/23/2022]
Abstract
Investigation of the homeostasis of red blood cells upon infection by Plasmodium falciparum poses complex experimental challenges. Changes in red cell shape, volume, protein, and ion balance are difficult to quantify. In this article, we review a wide range of optical techniques for quantitative measurements of critical homeostatic parameters in malaria-infected red blood cells. Fluorescence lifetime imaging and tomographic phase microscopy, quantitative deconvolution microscopy, and X-ray microanalysis, are used to measure haemoglobin concentration, cell volume, and ion contents. Atomic force microscopy is briefly reviewed in the context of these optical methodologies. We also describe how optical tweezers and optical stretchers can be usefully applied to empower basic malaria research to yield diagnostic information on cell compliance changes upon malaria infection. The combined application of these techniques sheds new light on the detailed mechanisms of malaria infection providing potential for new diagnostic or therapeutic approaches.
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Affiliation(s)
- Jakob M A Mauritz
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
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