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Ramachandra R, Mackey MR, Hu J, Peltier ST, Xuong N, Ellisman MH, Adams SR. Elemental mapping of labelled biological specimens at intermediate energy loss in an energy-filtered TEM acquired using a direct detection device. J Microsc 2021; 283:127-144. [PMID: 33844293 PMCID: PMC8316382 DOI: 10.1111/jmi.13014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/11/2021] [Accepted: 04/04/2021] [Indexed: 12/30/2022]
Abstract
The technique of colour EM that was recently developed enabled localisation of specific macromolecules/proteins of interest by the targeted deposition of diaminobenzidine (DAB) conjugated to lanthanide chelates. By acquiring lanthanide elemental maps by energy-filtered transmission electron microscopy (EFTEM) and overlaying them in pseudo-colour over the conventional greyscale TEM image, a colour EM image is generated. This provides a powerful tool for visualising subcellular component/s, by the ability to clearly distinguish them from the general staining of the endogenous cellular material. Previously, the lanthanide elemental maps were acquired at the high-loss M4,5 edge (excitation of 3d electrons), where the characteristic signal is extremely low and required considerably long exposures. In this paper, we explore the possibility of acquiring the elemental maps of lanthanides at their N4,5 edge (excitation of 4d electrons), which occurring at a much lower energy-loss regime, thereby contains significantly greater total characteristic signal owing to the higher inelastic scattering cross-sections at the N4,5 edge. Acquiring EFTEM lanthanide elemental maps at the N4,5 edge instead of the M4,5 edge, provides ∼4× increase in signal-to-noise and ∼2× increase in resolution. However, the interpretation of the lanthanide maps acquired at the N4,5 edge by the traditional 3-window method, is complicated due to the broad shape of the edge profile and the lower signal-above-background ratio. Most of these problems can be circumvented by the acquisition of elemental maps with the more sophisticated technique of EFTEM Spectrum Imaging (EFTEM SI). Here, we also report the chemical synthesis of novel second-generation DAB lanthanide metal chelate conjugates that contain 2 lanthanide ions per DAB molecule in comparison with 0.5 lanthanide ion per DAB in the first generation. Thereby, fourfold more Ln3+ per oxidised DAB would be deposited providing significant amplification of signal. This paper applies the colour EM technique at the intermediate-loss energy-loss regime to three different cellular targets, namely using mitochondrial matrix-directed APEX2, histone H2B-Nucleosome and EdU-DNA. All the examples shown in the paper are single colour EM images only.
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Affiliation(s)
- Ranjan Ramachandra
- Department of NeurosciencesUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
- Center for Research in Biological Systems, National Center for Microscopy and, Imaging ResearchUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
| | - Mason R. Mackey
- Department of NeurosciencesUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
- Center for Research in Biological Systems, National Center for Microscopy and, Imaging ResearchUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
| | - Junru Hu
- Department of NeurosciencesUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
- Center for Research in Biological Systems, National Center for Microscopy and, Imaging ResearchUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
| | - Steven T. Peltier
- Department of NeurosciencesUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
- Center for Research in Biological Systems, National Center for Microscopy and, Imaging ResearchUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
| | - Nguyen‐Huu Xuong
- Center for Research in Biological Systems, National Center for Microscopy and, Imaging ResearchUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
| | - Mark H. Ellisman
- Department of NeurosciencesUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
- Center for Research in Biological Systems, National Center for Microscopy and, Imaging ResearchUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
| | - Stephen R. Adams
- Department of PharmacologyUniversity of CaliforniaSan DiegoLa JollaCaliforniaUSA
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Ramachandra R, Bouwer JC, Mackey MR, Bushong E, Peltier ST, Xuong NH, Ellisman MH. Improving signal to noise in labeled biological specimens using energy-filtered TEM of sections with a drift correction strategy and a direct detection device. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:706-14. [PMID: 24641915 PMCID: PMC4178974 DOI: 10.1017/s1431927614000452] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Energy filtered transmission electron microscopy techniques are regularly used to build elemental maps of spatially distributed nanoparticles in materials and biological specimens. When working with thick biological sections, electron energy loss spectroscopy techniques involving core-loss electrons often require exposures exceeding several minutes to provide sufficient signal to noise. Image quality with these long exposures is often compromised by specimen drift, which results in blurring and reduced resolution. To mitigate drift artifacts, a series of short exposure images can be acquired, aligned, and merged to form a single image. For samples where the target elements have extremely low signal yields, the use of charge coupled device (CCD)-based detectors for this purpose can be problematic. At short acquisition times, the images produced by CCDs can be noisy and may contain fixed pattern artifacts that impact subsequent correlative alignment. Here we report on the use of direct electron detection devices (DDD's) to increase the signal to noise as compared with CCD's. A 3× improvement in signal is reported with a DDD versus a comparably formatted CCD, with equivalent dose on each detector. With the fast rolling-readout design of the DDD, the duty cycle provides a major benefit, as there is no dead time between successive frames.
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Affiliation(s)
- Ranjan Ramachandra
- Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - James C. Bouwer
- Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Mason R. Mackey
- Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Eric Bushong
- Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Steven T. Peltier
- Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Nguyen-Huu Xuong
- Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Mark H. Ellisman
- Center for Research in Biological Systems, National Center for Microscopy and Imaging Research, University of California at San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
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Egerton RF. TEM-EELS: a personal perspective. Ultramicroscopy 2012; 119:24-32. [PMID: 22221958 DOI: 10.1016/j.ultramic.2011.11.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 10/25/2011] [Accepted: 11/14/2011] [Indexed: 12/01/2022]
Abstract
The development of electron energy-loss spectroscopy in a transmission electron microscope (TEM-EELS) is illustrated through personal anecdote, highlighting some of the basic principles, instrumentation and personalities involved. The current state of the art is reviewed, together with some challenges for the future.
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Affiliation(s)
- R F Egerton
- Physics Department, University of Alberta, Edmonton, Canada T6G 2E1.
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Haider M, Epstein A, Jarron P, Boulin C. A versatile, software configurable multichannel STEM detector for angle-resolved imaging. Ultramicroscopy 1994. [DOI: 10.1016/0304-3991(94)90091-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Egerton R, Yang YY, Cheng S. Characterization and use of the Gatan 666 parallel-recording electron energy-loss spectrometer. Ultramicroscopy 1993. [DOI: 10.1016/0304-3991(93)90098-i] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Weiss J, Carpenter R. Factors limiting the spatial resolution and sensitivity of EELS microanalysis in a STEM. Ultramicroscopy 1992. [DOI: 10.1016/0304-3991(92)90131-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Yoshida K, Takaoka A, Ura K, Katsuta T, Matsui I. Grooved fluorescent plate for parallel-detection electron energy loss spectroscopy in ultra-high-voltage electron microscopy. Ultramicroscopy 1991. [DOI: 10.1016/0304-3991(91)90180-e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Reimer L. Energy-Filtering Transmission Electron Microscopy. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/s0065-2539(08)60863-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Bouchet D, Colliex C, Flora P, Krivanek O, Mory C, Tencé M. Analytical electron microscopy at the atomic level with parallel electron energy loss spectroscopy. ACTA ACUST UNITED AC 1990. [DOI: 10.1051/mmm:0199000105-6044300] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Zaluzec NJ, Strauss MG. Two-dimensional CCD arrays as parallel detectors in electron- energy-loss and X-ray wavelength-dispersive spectroscopy. Ultramicroscopy 1989. [DOI: 10.1016/0304-3991(89)90285-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Jeanguillaume C, Colliex C. Spectrum-image: The next step in EELS digital acquisition and processing. Ultramicroscopy 1989. [DOI: 10.1016/0304-3991(89)90304-5] [Citation(s) in RCA: 301] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Crozier P, Egerton R. Mass-thickness determination by Bethe-sum-rule normalization of the electron energy-loss spectrum. Ultramicroscopy 1989. [DOI: 10.1016/0304-3991(89)90197-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
The potential for applying electron energy loss spectroscopy (EELS) in biology is assessed. Some recent developments in instrumentation, spectrometer design, parallel detection and elemental mapping are discussed. Quantitation is demonstrated by means of the spectrum from DNA which gives an elemental ratio for N:P close to the expected value. A range of biologically important elements that can be usefully analyzed by EELS is tabulated and some possible applications for each are indicated. Detection limits and the effects of radiation damage are illustrated by spectra from the protein, insulin, and from the fluorinated amino-acid, histidine. Calcium detectability under optimum conditions may be as low as 1 mmol/kg dry weight. The application of EELS to analysis of cryosectioned adrenomedullary (chromaffin) cells is described in order to help determine the composition of the secretory granule. Water content can be determined from the amount of inelastic scattering as measured by the low-loss spectrum. The nitrogen/phosphorus ratio can be measured to provide information about the relative concentrations of ATP, chromogranin, and catecholamines. Quantitative EELS elemental maps are obtained in the STEM mode from chromaffin cells in order to measure the distribution of light elements.
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Affiliation(s)
- R D Leapman
- Biomedical Engineering and Instrumentation Branch, National Institutes of Health, Bethesda, Maryland 20892
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Johnson D, Izutsu K, Cantino M, Wong J. High spatial resolution spectroscopy in the elemental microanalysis and imaging of biological systems. Ultramicroscopy 1988; 24:221-35. [PMID: 3281356 DOI: 10.1016/0304-3991(88)90312-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The application of analytical electron microscopy to the high spatial resolution study of biological systems is reviewed. Specimen preparation, quantitative analysis, capabilities and limitations are all discussed, principally in the context of energy-dispersive X-ray analysis. Results are presented using both current techniques and the developing quantitative image analysis. Finally the role of new instrumental approaches, including electron energy loss spectrometry, is discussed.
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Affiliation(s)
- D Johnson
- Center for Bioengineering, University of Washington, Seattle 98195
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Leapman RD, Fiori CE, Gorlen KE. Elemental imaging by EELS and EDXS in the analytical electron microscope : Its relevance to trace element research. Biol Trace Elem Res 1987; 13:89-102. [PMID: 24254668 DOI: 10.1007/bf02796624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (EDXS) can be used to obtain elemental maps from thin biological samples in the analytical electron microscope. The EELS is particularly sensitive for the low-atomic-number elements, including C, N, and O, as well as other elements with favorable ionization cross-sections, such as Fe. The EDXS is useful for a complementary range of atoms, such as P, S, K, and Ca. A system is described for obtaining elemental distributions in an analytical electron microscope operated in the scanning transmission mode at 100-200 keV beam energy. The spatial resolution is typically limited to 10-20 nm when a conventional source is used. A satellite microcomputer controls acquisition of EELS and EDXS data from successive pixels in an image. These data are processed "on-the-fly" by a host computer to remove the noncharacteristic background intensity. Resulting images are stored on disk and can be analyzed by means of an image display system controlled by interactive software. The technique is demonstrated with elemental maps from two samples: alveolar macrophages containing respirable particles; and pancreatic beta cells that secrete insulin.
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Affiliation(s)
- R D Leapman
- National Institutes of Health, 20892, Bethesda, MD
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Strauss M, Naday I, Sherman I, Zaluzec N. CCD-based parallel detection system for electron energy-loss spectroscopy and imaging. Ultramicroscopy 1987. [DOI: 10.1016/0304-3991(87)90055-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Krivanek O, Ahn C, Keeney R. Parallel detection electron spectrometer using quadrupole lenses. Ultramicroscopy 1987. [DOI: 10.1016/0304-3991(87)90054-4] [Citation(s) in RCA: 172] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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Leapman RD. Scanning transmission electron microscope (STEM) elemental mapping by electron energy-loss spectroscopy. Ann N Y Acad Sci 1986; 483:326-38. [PMID: 3551725 DOI: 10.1111/j.1749-6632.1986.tb34539.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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