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Ju Y, Ro HJ, Yi YS, Cho T, Kim SI, Yoon CW, Jun S, Kim J. Three-Dimensional TEM Study of Dendrimer-Encapsulated Pt Nanoparticles for Visualizing Structural Characteristics of the Whole Organic-Inorganic Hybrid Nanostructure. Anal Chem 2021; 93:2871-2878. [PMID: 33455155 DOI: 10.1021/acs.analchem.0c04264] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Here, we report three-dimensional (3-D) visualization of dendrimer-encapsulated Pt nanoparticles (Pt DENs) by using 3-D electron tomography to reveal intricate structural characteristics of their whole organic-inorganic hybrid nanostructure. We reconstructed the 3-D spatial volume of Pt DENs by back-projecting a tilt series of two-dimensional (2-D) projections of Pt nanoparticles encapsulated inside dendrimers negatively stained with uranyl acetate. The direct 3-D visualization of Pt DENs elucidated their encapsulation characteristics with the spatial imaging of Pt nanoparticles embraced inside dendrimers in three dimensions. The encapsulation characteristics of Pt DENs were further verified with selective electrochemical poisoning experiments. In addition, quantitative 3-D structural characterization of Pt DENs provided more accurate and precise size distributions of nanoparticles than those obtained from conventional 2-D transmission electron microscopy analysis relying only on a 3-D structure projected on a 2-D plane.
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Affiliation(s)
- Youngwon Ju
- Department of Chemistry, Research Institute for Basic Sciences, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Hyun-Joo Ro
- Center for Research Equipment, Korea Basic Science Institute, Cheongju 28119, Republic of Korea.,Center for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
| | - Yoon-Sun Yi
- Center for Research Equipment, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
| | - Taehoon Cho
- Department of Chemistry, Research Institute for Basic Sciences, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Seung Il Kim
- Center for Research Equipment, Korea Basic Science Institute, Cheongju 28119, Republic of Korea.,Center for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
| | - Chang Won Yoon
- Center for Hydrogen and Fuel Cell Research, Korea Institute of Science and Technology (KIST), Seoul 02447, Republic of Korea.,KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Sangmi Jun
- Center for Research Equipment, Korea Basic Science Institute, Cheongju 28119, Republic of Korea.,Center for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
| | - Joohoon Kim
- Department of Chemistry, Research Institute for Basic Sciences, Kyung Hee University, Seoul 02447, Republic of Korea.,KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul 02447, Republic of Korea
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Sanchez RM, Zhang Y, Chen W, Dietrich L, Kudryashev M. Subnanometer-resolution structure determination in situ by hybrid subtomogram averaging - single particle cryo-EM. Nat Commun 2020; 11:3709. [PMID: 32709843 PMCID: PMC7381653 DOI: 10.1038/s41467-020-17466-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/30/2020] [Indexed: 11/09/2022] Open
Abstract
Cryo-electron tomography combined with subtomogram averaging (StA) has yielded high-resolution structures of macromolecules in their native context. However, high-resolution StA is not commonplace due to beam-induced sample drift, images with poor signal-to-noise ratios (SNR), challenges in CTF correction, and limited particle number. Here we address these issues by collecting tilt series with a higher electron dose at the zero-degree tilt. Particles of interest are then located within reconstructed tomograms, processed by conventional StA, and then re-extracted from the high-dose images in 2D. Single particle analysis tools are then applied to refine the 2D particle alignment and generate a reconstruction. Use of our hybrid StA (hStA) workflow improved the resolution for tobacco mosaic virus from 7.2 to 4.4 Å and for the ion channel RyR1 in crowded native membranes from 12.9 to 9.1 Å. These resolution gains make hStA a promising approach for other StA projects aimed at achieving subnanometer resolution.
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Affiliation(s)
- Ricardo M Sanchez
- Max Planck Institute for Biophysics, Max-von-Laue Strasse, 3, 60348, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University of Frankfurt am Main, Max-von-Laue Strasse, 15, 60348, Frankfurt am Main, Germany
| | - Yingyi Zhang
- Max Planck Institute for Biophysics, Max-von-Laue Strasse, 3, 60348, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University of Frankfurt am Main, Max-von-Laue Strasse, 15, 60348, Frankfurt am Main, Germany
| | - Wenbo Chen
- Max Planck Institute for Biophysics, Max-von-Laue Strasse, 3, 60348, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University of Frankfurt am Main, Max-von-Laue Strasse, 15, 60348, Frankfurt am Main, Germany
| | - Lea Dietrich
- Department of Structural Biology, Max Planck Institute for Biophysics, Max-von-Laue Strasse, 3, 60348, Frankfurt am Main, Germany
| | - Mikhail Kudryashev
- Max Planck Institute for Biophysics, Max-von-Laue Strasse, 3, 60348, Frankfurt am Main, Germany.
- Buchmann Institute for Molecular Life Sciences, Goethe University of Frankfurt am Main, Max-von-Laue Strasse, 15, 60348, Frankfurt am Main, Germany.
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