1
|
Caffrey BJ, Pedrazo-Tardajos A, Liberti E, Gaunt B, Kim JS, Kirkland AI. Liquid Phase Electron Microscopy of Bacterial Ultrastructure. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2402871. [PMID: 39239997 DOI: 10.1002/smll.202402871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/05/2024] [Indexed: 09/07/2024]
Abstract
Recent advances in liquid phase scanning transmission electron microscopy (LP-STEM) have enabled the study of dynamic biological processes at nanometer resolutions, paving the way for live-cell imaging using electron microscopy. However, this technique is often hampered by the inherent thickness of whole cell samples and damage from electron beam irradiation. These restrictions degrade image quality and resolution, impeding biological interpretation. Using graphene encapsulation, scanning transmission electron microscopy (STEM), and energy-dispersive X-ray (EDX) spectroscopy to mitigate these issues provides unprecedented levels of intracellular detail in aqueous specimens. This study demonstrates the potential of LP-STEM to examine and identify internal cellular structures in thick biological samples. Specifically, it highlights the use of LP-STEM to investigate the radiation resistant, gram-positive bacterium, Deinococcus radiodurans using various imaging techniques.
Collapse
Affiliation(s)
- Brian J Caffrey
- The Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OX11 OQX, UK
| | - Adrián Pedrazo-Tardajos
- The Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OX11 OQX, UK
| | - Emanuela Liberti
- The Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OX11 OQX, UK
| | - Benjamin Gaunt
- The Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OX11 OQX, UK
- Nuffield Department of Women's & Reproductive Health, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Judy S Kim
- The Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OX11 OQX, UK
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
| | - Angus I Kirkland
- The Rosalind Franklin Institute, Harwell Science and Innovation Campus, Didcot, OX11 OQX, UK
- Department of Materials, University of Oxford, Oxford, OX1 3PH, UK
| |
Collapse
|
2
|
Smith JW, Carnevale LN, Das A, Chen Q. Electron videography of a lipid-protein tango. SCIENCE ADVANCES 2024; 10:eadk0217. [PMID: 38630809 PMCID: PMC11023515 DOI: 10.1126/sciadv.adk0217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 03/15/2024] [Indexed: 04/19/2024]
Abstract
Biological phenomena, from enzymatic catalysis to synaptic transmission, originate in the structural transformations of biomolecules and biomolecular assemblies in liquid water. However, directly imaging these nanoscopic dynamics without probes or labels has been a fundamental methodological challenge. Here, we developed an approach for "electron videography"-combining liquid phase electron microscopy with molecular modeling-with which we filmed the nanoscale structural fluctuations of individual, suspended, and unlabeled membrane protein nanodiscs in liquid. Systematic comparisons with biochemical data and simulation indicate the graphene encapsulation involved can afford sufficiently reduced effects of the illuminating electron beam for these observations to yield quantitative fingerprints of nanoscale lipid-protein interactions. Our results suggest that lipid-protein interactions delineate dynamically modified membrane domains across unexpectedly long ranges. Moreover, they contribute to the molecular mechanics of the nanodisc as a whole in a manner specific to the protein within. Overall, this work illustrates an experimental approach to film, quantify, and understand biomolecular dynamics at the nanometer scale.
Collapse
Affiliation(s)
- John W. Smith
- Department of Materials Science and Engineering, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
| | - Lauren N. Carnevale
- Department of Biochemistry, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
| | - Aditi Das
- School of Chemistry and Biochemistry, Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Qian Chen
- Department of Materials Science and Engineering, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
- Department of Chemistry, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
- Materials Research Laboratory, University of Illinois Urbana–Champaign, Urbana, IL 61801, USA
| |
Collapse
|
3
|
Egerton RF. Voxel dose-limited resolution for thick beam-sensitive specimens imaged in a TEM or STEM. Micron 2024; 177:103576. [PMID: 38113715 DOI: 10.1016/j.micron.2023.103576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/09/2023] [Accepted: 12/10/2023] [Indexed: 12/21/2023]
Abstract
The resolution limit imposed by radiation damage is quantified in terms of a voxel dose-limited resolution (DLR), applicable to small features within a thick specimen. An analytical formula for this DLR is derived and applied to bright-field mass-thickness contrast from organic (polymer or biological) specimens of thickness between 400 nm and 20 µm. For a permissible dose of 330 MGy (typical of frozen-hydrated tissue), the TEM or STEM image resolution is determined by radiation damage rather than by lens aberrations or beam-broadening effects, which can be restricted by use of a small angle-limiting aperture. DLR is improved by a up to factor of 2 by increasing the primary-electron energy from 300 keV to 3 MeV, or by up to a factor of 3 by heavy-metal staining. For stained samples, a higher electron fluence allows better resolution but the improvement is modest because the voxel DLR is proportional to the 1/4 power of electron dose. The relevance of voxel and columnar DLR is discussed, for both thick and thin samples.
Collapse
Affiliation(s)
- R F Egerton
- Physics Department, University of Alberta, Edmonton T6G 2E1, Canada
| |
Collapse
|
4
|
Sasaki Y, Mizushima A, Mita Y, Yoshida K, Kuwabara A, Ikuhara Y. Design and Fabrication of an Electrochemical Chip for Liquid-Phase Transmission Electron Microscopy. Microscopy (Oxf) 2022; 71:238-241. [PMID: 35512147 DOI: 10.1093/jmicro/dfac023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/25/2022] [Accepted: 05/03/2022] [Indexed: 11/13/2022] Open
Abstract
Liquid-phase transmission electron microscopy (LP-TEM) can be used with an electrochemical chip (e-chip) to observe electrochemical reactions in a liquid in situ. The design of electrodes on an e-chip fabricated using microelectromechanical system (MEMS) technology cannot be easily changed. Here, we report a newly designed e-chip and its fabrication process. Electrodes with a desired shape were fabricated with various metals via an additional step of vacuum deposition onto our e-chip with a shadow mask. For precise control of the electrochemical reactions in LP-TEM, optimization of the electrode shape and material is critical.
Collapse
Affiliation(s)
- Yuki Sasaki
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
| | - Ayako Mizushima
- Department of Electrical Engineering and Information Systems, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Yoshio Mita
- Department of Electrical Engineering and Information Systems, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kaname Yoshida
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
| | - Akihide Kuwabara
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan
| | - Yuichi Ikuhara
- Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan.,Institute of Engineering Innovation, School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan
| |
Collapse
|
5
|
Zhang Z, Guo H, Liu B, Xian D, Liu X, Da B, Sun L. Understanding Complex Electron Radiolysis in Saline Solution by Big Data Analysis. ACS OMEGA 2022; 7:15113-15122. [PMID: 35572744 PMCID: PMC9089687 DOI: 10.1021/acsomega.2c01010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 04/08/2022] [Indexed: 06/15/2023]
Abstract
In this article, we developed a new method to analyze the complex chemical reactions induced by electron beam radiolysis based on big data analysis. At first, we built an element transport network to show the chemical reactions. Furthermore, the linearity between the species was quantified by Pearson correlation coefficient analysis. Based on the analysis, the mechanism of the high linearity between the special species pairs was interpreted by the element transport roadmap and chemical equations. The time variation of the pH of the solution and bubble formation in the solution were analyzed by simulation and data analysis. The simulation indicates that O2 and H2 can easily oversaturate and form bubbles. Finally, the radiolysis of high-energy electrons in pure water was analyzed as a reference for the radiolysis of high-energy electrons in saline solution. This work provides a new method for investigating a high-energy electron radiolysis process and for simplifying a complex chemical reaction based on quantitative analysis of the species variation in the reaction.
Collapse
Affiliation(s)
- Zhihao Zhang
- SEU-FEI
Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education,
School of Electronic Science and Engineering, Southeast University, Nanjing 210096, People’s Republic
of China
| | - Hongxuan Guo
- SEU-FEI
Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education,
School of Electronic Science and Engineering, Southeast University, Nanjing 210096, People’s Republic
of China
- Center
for Advanced Materials and Manufacture, Joint Research Institute of Southeast University and Monash University, Suzhou 215123, People’s Republic of China
| | - Bo Liu
- SEU-FEI
Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education,
School of Electronic Science and Engineering, Southeast University, Nanjing 210096, People’s Republic
of China
| | - Dali Xian
- SEU-FEI
Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education,
School of Electronic Science and Engineering, Southeast University, Nanjing 210096, People’s Republic
of China
| | - Xuanxuan Liu
- SEU-FEI
Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education,
School of Electronic Science and Engineering, Southeast University, Nanjing 210096, People’s Republic
of China
| | - Bo Da
- Research
and Services Division of Materials Data and Integrated System, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Litao Sun
- SEU-FEI
Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education,
School of Electronic Science and Engineering, Southeast University, Nanjing 210096, People’s Republic
of China
- Center
for Advanced Materials and Manufacture, Joint Research Institute of Southeast University and Monash University, Suzhou 215123, People’s Republic of China
| |
Collapse
|
6
|
Wu H, Friedrich H, Patterson JP, Sommerdijk NAJM, de Jonge N. Liquid-Phase Electron Microscopy for Soft Matter Science and Biology. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2001582. [PMID: 32419161 DOI: 10.1002/adma.202001582] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/05/2020] [Accepted: 04/06/2020] [Indexed: 05/20/2023]
Abstract
Innovations in liquid-phase electron microscopy (LP-EM) have made it possible to perform experiments at the optimized conditions needed to examine soft matter. The main obstacle is conducting experiments in such a way that electron beam radiation can be used to obtain answers for scientific questions without changing the structure and (bio)chemical processes in the sample due to the influence of the radiation. By overcoming these experimental difficulties at least partially, LP-EM has evolved into a new microscopy method with nanometer spatial resolution and sub-second temporal resolution for analysis of soft matter in materials science and biology. Both experimental design and applications of LP-EM for soft matter materials science and biological research are reviewed, and a perspective of possible future directions is given.
Collapse
Affiliation(s)
- Hanglong Wu
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
| | - Heiner Friedrich
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, 5600 MB, The Netherlands
| | - Joseph P Patterson
- Department of Chemistry, University of California, Irvine, CA, 92697, USA
| | - Nico A J M Sommerdijk
- Department of Biochemistry, Radboud University Medical Center, Nijmegen, 6500 HB, The Netherlands
| | - Niels de Jonge
- INM - Leibniz Institute for New Materials, Saarbrücken, 66123, Germany
- Department of Physics, Saarland University, Saarbrücken, 66123, Germany
| |
Collapse
|
7
|
Narayanan S, Shahbazian-Yassar R, Shokuhfar T. In Situ Visualization of Ferritin Biomineralization via Graphene Liquid Cell-Transmission Electron Microscopy. ACS Biomater Sci Eng 2020; 6:3208-3216. [PMID: 33463263 DOI: 10.1021/acsbiomaterials.9b01889] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ferritin biomineralization is essential to regulate the toxic Fe2+ iron ions in the human body. Unravelling the mechanism of biomineralization in ferritin facilitates our understanding of the causes underlying many iron disorder-related diseases. Until now, no report of in situ visualization of ferritin biomineralization events at nanoscale exists due to the requirement for high-resolution imaging of nanometer-sized ferritin proteins in their hydrated states. Herein, for the first time, we show that the biomineralization processes within individual ferritin proteins can be visualized by means of graphene liquid cell-transmission electron microscopy (GLC-TEM). The increase in the ratio of Fe3+/Fe2+ ions over time monitored via electron energy loss spectroscopy (EELS) reveals the change in oxidation state of iron oxide phases with time. This study lays a foundation for future investigations on iron regulation mechanisms in healthy and dysfunctional ferritins.
Collapse
Affiliation(s)
- Surya Narayanan
- Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, Chicago, Illinois 60607, United States
| | - Reza Shahbazian-Yassar
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, 842 West Taylor Street, Chicago, Illinois 60607, United States
| | - Tolou Shokuhfar
- Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, Chicago, Illinois 60607, United States
| |
Collapse
|
8
|
Smith JW, Chen Q. Liquid-phase electron microscopy imaging of cellular and biomolecular systems. J Mater Chem B 2020; 8:8490-8506. [DOI: 10.1039/d0tb01300e] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Liquid-phase electron microscopy, a new method for real-time nanoscopic imaging in liquid, makes it possible to study cells or biomolecules with a singular combination of spatial and temporal resolution. We review the state of the art in biological research in this growing and promising field.
Collapse
Affiliation(s)
- John W. Smith
- Department of Materials Science and Engineering, University of Illinois at Urbana–Champaign
- Urbana
- USA
| | - Qian Chen
- Department of Materials Science and Engineering, University of Illinois at Urbana–Champaign
- Urbana
- USA
- Department of Chemistry
- University of Illinois at Urbana–Champaign
| |
Collapse
|
9
|
Pu S, Gong C, Robertson AW. Liquid cell transmission electron microscopy and its applications. ROYAL SOCIETY OPEN SCIENCE 2020; 7:191204. [PMID: 32218950 PMCID: PMC7029903 DOI: 10.1098/rsos.191204] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/19/2019] [Indexed: 06/10/2023]
Abstract
Transmission electron microscopy (TEM) has long been an essential tool for understanding the structure of materials. Over the past couple of decades, this venerable technique has undergone a number of revolutions, such as the development of aberration correction for atomic level imaging, the realization of cryogenic TEM for imaging biological specimens, and new instrumentation permitting the observation of dynamic systems in situ. Research in the latter has rapidly accelerated in recent years, based on a silicon-chip architecture that permits a versatile array of experiments to be performed under the high vacuum of the TEM. Of particular interest is using these silicon chips to enclose fluids safely inside the TEM, allowing us to observe liquid dynamics at the nanoscale. In situ imaging of liquid phase reactions under TEM can greatly enhance our understanding of fundamental processes in fields from electrochemistry to cell biology. Here, we review how in situ TEM experiments of liquids can be performed, with a particular focus on microchip-encapsulated liquid cell TEM. We will cover the basics of the technique, and its strengths and weaknesses with respect to related in situ TEM methods for characterizing liquid systems. We will show how this technique has provided unique insights into nanomaterial synthesis and manipulation, battery science and biological cells. A discussion on the main challenges of the technique, and potential means to mitigate and overcome them, will also be presented.
Collapse
|
10
|
Kashin AS, Ananikov VP. Monitoring chemical reactions in liquid media using electron microscopy. Nat Rev Chem 2019. [DOI: 10.1038/s41570-019-0133-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
11
|
Narayanan S, Firlar E, Rasul MG, Foroozan T, Farajpour N, Covnot L, Shahbazian-Yassar R, Shokuhfar T. On the structure and chemistry of iron oxide cores in human heart and human spleen ferritins using graphene liquid cell electron microscopy. NANOSCALE 2019; 11:16868-16878. [PMID: 31482911 DOI: 10.1039/c9nr01541h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ferritin is a protein that regulates the iron ions in humans by storing them in the form of iron oxides. Despite extensive efforts to understand the ferritin iron oxide structures, it is still not clear how ferritin proteins with a distinct light (L) and heavy (H) chain subunit ratio impact the biomineralization process. In situ graphene liquid cell-transmission electron microscopy (GLC-TEM) provides an indispensable platform to study the atomic structure of ferritin mineral cores in their native liquid environment. In this study, we report differences in the iron oxide formation in human spleen ferritins (HSFs) and human heart ferritins (HHFs) using in situ GLC-TEM. Scanning transmission electron microscopy (STEM) along with selected area electron diffraction (SAED) of the mineral core and electron energy loss spectroscopy (EELS) analyses enabled the visualization of morphologies, crystal structures and the chemistry of iron oxide cores in HSFs and HHFs. Our study revealed the presence of metastable ferrihydrite (5Fe2O3·9H2O) as a dominant phase in hydrated HSFs and HHFs, while a stable hematite (α-Fe2O3) phase predominated in non-hydrated HSFs and HHFs. In addition, a higher Fe3+/Fe2+ ratio was found in HHFs in comparison with HSFs. This study provides new understanding on iron-oxide phases that exist in hydrated ferritin proteins from different human organs. Such new insights are needed to map ferritin biomineralization pathways and possible correlations with various iron-related disorders in humans.
Collapse
Affiliation(s)
- Surya Narayanan
- University of Illinois at Chicago, Department of Bioengineering, Chicago, IL 60607, USA.
| | | | | | | | | | | | | | | |
Collapse
|
12
|
He K, Shokuhfar T, Shahbazian-Yassar R. Imaging of soft materials using in situ liquid-cell transmission electron microscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:103001. [PMID: 30524096 DOI: 10.1088/1361-648x/aaf616] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This review summarizes the breakthroughs in the field of soft material characterization by in situ liquid-cell transmission electron microscopy (TEM). The focus of this review is mostly on soft biological species such as cells, bacteria, viruses, proteins and polymers. The comparison between the two main liquid-cell systems (silicon nitride membranes liquid cell and graphene liquid cell) is also discussed in terms of their spatial resolution and imaging/analytical capabilities. We have showcased how liquid-cell TEM can reveal the structural details of whole cells, enable the chemical probing of proteins, detect the structural conformation of viruses, and monitor the dynamics of polymerization. In addition, the challenges faced by decoupling electron beam effect on beam-sensitive soft materials are discussed. At the end, future perspectives of in situ liquid-cell TEM studies of soft materials are outlined.
Collapse
Affiliation(s)
- Kun He
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL 60607, United States of America
| | | | | |
Collapse
|
13
|
Londono-Calderon A, Nayak S, Mosher CL, Mallapragada SK, Prozorov T. New approach to electron microscopy imaging of gel nanocomposites in situ. Micron 2019; 120:104-112. [PMID: 30831277 DOI: 10.1016/j.micron.2019.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 02/20/2019] [Accepted: 02/20/2019] [Indexed: 12/28/2022]
Abstract
Characterization of Au-nanocomposites is routinely done with scattering techniques where the structure and ordering of nanoparticles can be analyzed. Imaging of Poloxamer gel-based Au-nanocomposites is usually limited to cryo-TEM imaging of cryo-microtomed thin sections of the specimen. While this approach is applicable for imaging of the individual nanoparticles and gauging their size distribution, it requires altering the state of the specimen and is prone to artifacts associated with preparation protocols. Use of Scanning Transmission Electron Microscopy (S/TEM) with fluid cell in situ provides an opportunity to analysis of these complex materials in their hydrated state with nanometer resolution, yet dispensing dense gel-based samples onto electron-transparent substrates remains challenging. We show that Poloxamer gel-based Au nanocomposites exhibiting thermoreversible behavior can be imaged in a fully hydrated state using a commercially available fluid cell holder, and we describe a specimen preparation method for depositing femtoliter amounts of gel-based nanocomposites directly onto the 50 nm-thick SiN window membranes. Ultimately, fluid cell S/TEM in situ imaging approach offers a pathway to visualization of individual nanoparticles within a thick gel media while maintaining the hydrated state of the carrier polymeric matrix.
Collapse
Affiliation(s)
| | - Srikanth Nayak
- Division of Materials Science and Engineering, US DOE Ames Laboratory, Ames, IA, 50011, United States; Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, United States
| | - Curtis L Mosher
- Roy J. Carver High Resolution Microscopy Facility, Iowa State University, Ames, IA, 50011, United States
| | - Surya K Mallapragada
- Division of Materials Science and Engineering, US DOE Ames Laboratory, Ames, IA, 50011, United States; Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, United States
| | - Tanya Prozorov
- Division of Materials Science and Engineering, US DOE Ames Laboratory, Ames, IA, 50011, United States.
| |
Collapse
|
14
|
Luo XL, Li JX, Huang HR, Duan JL, Dai RX, Tao RJ, Yang L, Hou JY, Jia XM, Xu JF. LL37 Inhibits Aspergillus fumigatus Infection via Directly Binding to the Fungus and Preventing Excessive Inflammation. Front Immunol 2019; 10:283. [PMID: 30842778 PMCID: PMC6391356 DOI: 10.3389/fimmu.2019.00283] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Accepted: 02/04/2019] [Indexed: 12/13/2022] Open
Abstract
The incidence of Aspergillus fumigatus infection and the rate of resistance to antifungal drugs have sharply increased in recent years. LL37 has been reported as a host defense peptide with broad-spectrum antibacterial activities. However, the role of LL37 during A. fumigatus infection remains unclear. Here, we examined the interaction between LL37 and A. fumigatus and found that synthetic LL37 could directly bind to the surface of A. fumigatus, disrupting the integrity of the cell wall in vitro. LL37 inhibited mycelial growth in a concentration-dependent manner, rather than fungicidal effect even at high concentration (e.g., 20 μM). Interestingly, low concentrations of LL37 (e.g., 4 μM) significantly attenuated mycelial adhesion and prevented the invasion and destruction of epithelial cells. Following LL37 treatment, the levels of proinflammatory cytokines released by A. fumigatus-stimulated macrophages decreased significantly, accompanied by downregulation of M1 type markers. In a mouse model of pulmonary A. fumigatus infection, LL37-treated mice showed lower amounts of fungi load, moderate pathological damage, and reduced proinflammatory cytokines. Further, LL37 transgenic mice (LL37+/+) were examined to investigate the effects of endogenous LL37 in an A. fumigatus infection model and showed lower susceptibility to A. fumigatus infection in comparison with wild-type mice. In addition, LL37 also played a protective role in an immunosuppressed mouse model of A. fumigatus infection. Thus, LL37 inhibits A. fumigatus infection via directly binding to mycelia and reducing excessive inflammation. LL37 or its analogs may therefore constitute potential drug components for A. fumigatus infection.
Collapse
Affiliation(s)
- Xiao-Li Luo
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jian-Xiong Li
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Hua-Rong Huang
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jie-Lin Duan
- Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ruo-Xuan Dai
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ru-Jia Tao
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ling Yang
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jia-Yun Hou
- Zhongshan Hospital Institute of Clinical Science, Shanghai Institute of Clinical Bioinformatics, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xin-Ming Jia
- Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Jin-Fu Xu
- Department of Respiratory and Critical Care Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| |
Collapse
|
15
|
Moser TH, Shokuhfar T, Evans JE. Considerations for imaging thick, low contrast, and beam sensitive samples with liquid cell transmission electron microscopy. Micron 2018; 117:8-15. [PMID: 30419433 DOI: 10.1016/j.micron.2018.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/15/2018] [Accepted: 10/29/2018] [Indexed: 01/08/2023]
Abstract
Transmission electron microscopy of whole cells is hindered by the inherently large thickness and low atomic contrast intrinsic of cellular material. Liquid cell transmission electron microscopy allows samples to remain in their native hydrated state and may permit visualizing cellular dynamics in-situ. However, imaging biological cells with this approach remains challenging and identifying an optimal imaging regime using empirical data would help foster new advancements in the field. Recent questions about the role of the electron beam inducing morphological changes or damaging cellular structure and function necessitates further investigation of electron beam-cell interactions, but such comparisons are complicated by variability in imaging techniques used across various studies currently present in literature. The necessity for using low electron fluxes while imaging biological samples requires finding an imaging strategy which produces the strongest contrast and signal to noise ratio for the electron flux used. Here, we experimentally measure and evaluate signal to noise ratios and damage mechanisms between liquid and cryogenic samples of intact cells using multiple electron imaging modalities all on the same instrument and with equivalent beam parameters to standardize the comparison. We also discuss considerations for optimal electron microscopy imaging conditions for future studies on whole cells within liquid environments.
Collapse
Affiliation(s)
- Trevor H Moser
- Environmental Molecular Sciences Laboratory, 3335 Innovation Blvd., Richland, WA 99354, USA; Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931, USA
| | - Tolou Shokuhfar
- Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931, USA; University of Illinois Chicago, 1200 W. Harrison St., Chicago, IL 60607, USA
| | - James E Evans
- Environmental Molecular Sciences Laboratory, 3335 Innovation Blvd., Richland, WA 99354, USA; School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA.
| |
Collapse
|
16
|
de Jonge N. Theory of the spatial resolution of (scanning) transmission electron microscopy in liquid water or ice layers. Ultramicroscopy 2018; 187:113-125. [DOI: 10.1016/j.ultramic.2018.01.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 01/02/2018] [Accepted: 01/17/2018] [Indexed: 01/29/2023]
|
17
|
Moser TH, Mehta H, Park C, Kelly RT, Shokuhfar T, Evans JE. The role of electron irradiation history in liquid cell transmission electron microscopy. SCIENCE ADVANCES 2018; 4:eaaq1202. [PMID: 29725619 PMCID: PMC5930397 DOI: 10.1126/sciadv.aaq1202] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 03/13/2018] [Indexed: 05/25/2023]
Abstract
In situ liquid cell transmission electron microscopy (LC-TEM) allows dynamic nanoscale characterization of systems in a hydrated state. Although powerful, this technique remains impaired by issues of repeatability that limit experimental fidelity and hinder the identification and control of some variables underlying observed dynamics. We detail new LC-TEM devices that improve experimental reproducibility by expanding available imaging area and providing a platform for investigating electron flux history on the sample. Irradiation history is an important factor influencing LC-TEM results that has, to this point, been largely qualitatively and not quantitatively described. We use these devices to highlight the role of cumulative electron flux history on samples from both nanoparticle growth and biological imaging experiments and demonstrate capture of time zero, low-dose images on beam-sensitive samples. In particular, the ability to capture pristine images of biological samples, where the acquired image is the first time that the cell experiences significant electron flux, allowed us to determine that nanoparticle movement compared to the cell membrane was a function of cell damage and therefore an artifact rather than visualizing cell dynamics in action. These results highlight just a subset of the new science that is accessible with LC-TEM through the new multiwindow devices with patterned focusing aides.
Collapse
Affiliation(s)
- Trevor H. Moser
- Environmental Molecular Sciences Laboratory, 3335 Innovation Boulevard, Richland, WA 99354, USA
- Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
| | - Hardeep Mehta
- Environmental Molecular Sciences Laboratory, 3335 Innovation Boulevard, Richland, WA 99354, USA
| | - Chiwoo Park
- Florida State University, 600 West College Avenue, Tallahassee, FL 32306, USA
| | - Ryan T. Kelly
- Environmental Molecular Sciences Laboratory, 3335 Innovation Boulevard, Richland, WA 99354, USA
| | - Tolou Shokuhfar
- Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
- University of Illinois Chicago, 1200 West Harrison Street, Chicago, IL 60607, USA
| | - James E. Evans
- Environmental Molecular Sciences Laboratory, 3335 Innovation Boulevard, Richland, WA 99354, USA
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
| |
Collapse
|
18
|
DE JONGE N. Membrane protein stoichiometry studied in intact mammalian cells using liquid-phase electron microscopy. J Microsc 2017; 269:134-142. [DOI: 10.1111/jmi.12570] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/15/2017] [Accepted: 03/25/2017] [Indexed: 02/02/2023]
Affiliation(s)
- N. DE JONGE
- Leibniz Institute for New Materials; Saarbrücken Germany
- Department of Physics; University of Saarland; Saarbrücken Germany
| |
Collapse
|
19
|
Fukuta M, Ono A, Nawa Y, Inami W, Shen L, Kawata Y, Terekawa S. Cell structure imaging with bright and homogeneous nanometric light source. JOURNAL OF BIOPHOTONICS 2017; 10:503-510. [PMID: 27274004 DOI: 10.1002/jbio.201500308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 04/19/2016] [Accepted: 05/18/2016] [Indexed: 06/06/2023]
Abstract
Label-free optical nano-imaging of dendritic structures and intracellular granules in biological cells is demonstrated using a bright and homogeneous nanometric light source. The optical nanometric light source is excited using a focused electron beam. A zinc oxide (ZnO) luminescent thin film was fabricated by atomic layer deposition (ALD) to produce the nanoscale light source. The ZnO film formed by ALD emitted the bright, homogeneous light, unlike that deposited by another method. The dendritic structures of label-free macrophage receptor with collagenous structure-expressing CHO cells were clearly visualized below the diffraction limit. The inner fiber structure was observed with 120 nm spatial resolution. Because the bright homogeneous emission from the ZnO film suppresses the background noise, the signal-to-noise ratio (SNR) for the imaging results was greater than 10. The ALD method helps achieve an electron beam excitation assisted microscope with high spatial resolution and high SNR.
Collapse
Affiliation(s)
- Masahiro Fukuta
- Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka, Hamamatsu, 432-8561, Japan
| | - Atsushi Ono
- Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka, Hamamatsu, 432-8561, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honmachi, Kawaguchi, Saitama, 332-0012, Japan
| | - Yasunori Nawa
- Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka, Hamamatsu, 432-8561, Japan
| | - Wataru Inami
- Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka, Hamamatsu, 432-8561, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honmachi, Kawaguchi, Saitama, 332-0012, Japan
| | - Lin Shen
- CREST, Japan Science and Technology Agency, 4-1-8 Honmachi, Kawaguchi, Saitama, 332-0012, Japan
| | - Yoshimasa Kawata
- Research Institute of Electronics, Shizuoka University, 3-5-1 Johoku, Naka, Hamamatsu, 432-8561, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honmachi, Kawaguchi, Saitama, 332-0012, Japan
| | - Susumu Terekawa
- CREST, Japan Science and Technology Agency, 4-1-8 Honmachi, Kawaguchi, Saitama, 332-0012, Japan
- Photon Medical Research Center, Hamamatsu University School of Medicine, 1-20-1 Hondayama, Higashi, Hamamatsu, 431-3192, Japan
| |
Collapse
|
20
|
High-resolution imaging of living mammalian cells bound by nanobeads-connected antibodies in a medium using scanning electron-assisted dielectric microscopy. Sci Rep 2017; 7:43025. [PMID: 28230204 PMCID: PMC5322383 DOI: 10.1038/srep43025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/18/2017] [Indexed: 02/07/2023] Open
Abstract
Nanometre-scale-resolution imaging technologies for liquid-phase specimens are indispensable tools in various scientific fields. In biology, observing untreated living cells in a medium is essential for analysing cellular functions. However, nanoparticles that bind living cells in a medium are hard to detect directly using traditional optical or electron microscopy. Therefore, we previously developed a novel scanning electron-assisted dielectric microscope (SE-ADM) capable of nanoscale observations. This method enables observation of intact cells in aqueous conditions. Here, we use this SE-ADM system to clearly observe antibody-binding nanobeads in liquid-phase. We also report the successful direct detection of streptavidin-conjugated nanobeads binding to untreated cells in a medium via a biotin-conjugated anti-CD44 antibody. Our system is capable of obtaining clear images of cellular organelles and beads on the cells at the same time. The direct observation of living cells with nanoparticles in a medium allowed by our system may contribute the development of carriers for drug delivery systems (DDS).
Collapse
|
21
|
Besztejan S, Keskin S, Manz S, Kassier G, Bücker R, Venegas-Rojas D, Trieu HK, Rentmeister A, Miller RJD. Visualization of Cellular Components in a Mammalian Cell with Liquid-Cell Transmission Electron Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2017; 23:46-55. [PMID: 28137345 DOI: 10.1017/s1431927616012708] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present liquid-cell transmission electron microscopy (liquid-cell TEM) imaging of fixed and non-fixed prostate cancer cells (PC3 and LNCaP) with high resolution in a custom developed silicon nitride liquid cell. Fixed PC3 cells were imaged for 90-120 min without any discernable damage. High contrast on the cellular structures was obtained even at low electron doses (~2.5 e-/nm2 per image). The images show distinct structures of cell compartments (nuclei and nucleoli) and cell boundaries without any further sample embedding, dehydration, or staining. Furthermore, we observed dynamics of vesicles trafficking from the cell membrane in consecutive still frames in a non-fixed cell. Our findings show that liquid-cell TEM, operated at low electron dose, is an excellent tool to investigate dynamic events in non-fixed cells with enough spatial resolution (few nm) and natural amplitude contrast to follow key intracellular processes.
Collapse
Affiliation(s)
- Stephanie Besztejan
- 1Chemistry Department,Institute for Biochemistry and Molecular Biology,University of Hamburg,Martin-Luther-King Platz 6,20146 Hamburg,Germany
| | - Sercan Keskin
- 3Max Planck Institute for the Structure and Dynamics of Matter,Luruper Chaussee 149,Geb. 99 (CFEL),22761 Hamburg,Germany
| | - Stephanie Manz
- 3Max Planck Institute for the Structure and Dynamics of Matter,Luruper Chaussee 149,Geb. 99 (CFEL),22761 Hamburg,Germany
| | - Günther Kassier
- 3Max Planck Institute for the Structure and Dynamics of Matter,Luruper Chaussee 149,Geb. 99 (CFEL),22761 Hamburg,Germany
| | - Robert Bücker
- 3Max Planck Institute for the Structure and Dynamics of Matter,Luruper Chaussee 149,Geb. 99 (CFEL),22761 Hamburg,Germany
| | - Deybith Venegas-Rojas
- 4Institute of Microsystems Technology,Hamburg University of Technology (TUHH),Eißendorfer Straße 42,21073 Hamburg,Germany
| | - Hoc K Trieu
- 4Institute of Microsystems Technology,Hamburg University of Technology (TUHH),Eißendorfer Straße 42,21073 Hamburg,Germany
| | - Andrea Rentmeister
- 5Institute of Biochemistry,Westfälische Wilhelms-Universität Münster,Wilhelm-Klemm-Strasse 2,48149 Muenster,Germany
| | - R J Dwayne Miller
- 2The Hamburg Centre for Ultrafast Imaging,University of Hamburg, Luruper Chaussee 149,22761 Hamburg,Germany
| |
Collapse
|
22
|
Rez P, Larsen T, Elbaum M. Exploring the theoretical basis and limitations of cryo-STEM tomography for thick biological specimens. J Struct Biol 2016; 196:466-478. [DOI: 10.1016/j.jsb.2016.09.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/15/2016] [Accepted: 09/22/2016] [Indexed: 11/30/2022]
|
23
|
Dwyer JR, Bandara YMNDY, Whelan JC, Karawdeniya BI, Nichols JW. Silicon Nitride Thin Films for Nanofluidic Device Fabrication. NANOFLUIDICS 2016. [DOI: 10.1039/9781849735230-00190] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Silicon nitride is a ubiquitous and well-established nanofabrication material with a host of favourable properties for creating nanofluidic devices with a range of compelling designs that offer extraordinary discovery potential. Nanochannels formed between two thin silicon nitride windows can open up vistas for exploration by freeing transmission electron microscopy to interrogate static structures and structural dynamics in liquid-based samples. Nanopores present a strikingly different architecture—nanofluidic channels through a silicon nitride membrane—and are one of the most promising tools to emerge in biophysics and bioanalysis, offering outstanding capabilities for single molecule sensing. The constrained environments in such nanofluidic devices make surface chemistry a vital design and performance consideration. Silicon nitride has a rich and complex surface chemistry that, while too often formidable, can be tamed with new, robust surface functionalization approaches. We will explore how a simple structural element—a ∼100 nm-thick silicon nitride window—can be used to fabricate devices to wrest unprecedented insights from the nanoscale world. We will detail the intricacies of native silicon nitride surface chemistry, present surface chemical modification routes that leverage the richness of available surface moieties, and examine the effect of engineered chemical surface functionality on nanofluidic device character and performance.
Collapse
Affiliation(s)
- J. R. Dwyer
- University of Rhode Island, Department of Chemistry Kingston RI 02881 USA
| | | | - J. C. Whelan
- University of Rhode Island, Department of Chemistry Kingston RI 02881 USA
| | - B. I. Karawdeniya
- University of Rhode Island, Department of Chemistry Kingston RI 02881 USA
| | - J. W. Nichols
- University of Rhode Island, Department of Chemistry Kingston RI 02881 USA
| |
Collapse
|
24
|
Wu J, Shan H, Chen W, Gu X, Tao P, Song C, Shang W, Deng T. In Situ Environmental TEM in Imaging Gas and Liquid Phase Chemical Reactions for Materials Research. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:9686-9712. [PMID: 27628711 DOI: 10.1002/adma.201602519] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 06/10/2016] [Indexed: 05/26/2023]
Abstract
Gas and liquid phase chemical reactions cover a broad range of research areas in materials science and engineering, including the synthesis of nanomaterials and application of nanomaterials, for example, in the areas of sensing, energy storage and conversion, catalysis, and bio-related applications. Environmental transmission electron microscopy (ETEM) provides a unique opportunity for monitoring gas and liquid phase reactions because it enables the observation of those reactions at the ultra-high spatial resolution, which is not achievable through other techniques. Here, the fundamental science and technology developments of gas and liquid phase TEM that facilitate the mechanistic study of the gas and liquid phase chemical reactions are discussed. Combined with other characterization tools integrated in TEM, unprecedented material behaviors and reaction mechanisms are observed through the use of the in situ gas and liquid phase TEM. These observations and also the recent applications in this emerging area are described. The current challenges in the imaging process are also discussed, including the imaging speed, imaging resolution, and data management.
Collapse
Affiliation(s)
- Jianbo Wu
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai, 200240, People's Republic of China
| | - Hao Shan
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai, 200240, People's Republic of China
| | - Wenlong Chen
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai, 200240, People's Republic of China
| | - Xin Gu
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai, 200240, People's Republic of China
| | - Peng Tao
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai, 200240, People's Republic of China
| | - Chengyi Song
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai, 200240, People's Republic of China
| | - Wen Shang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai, 200240, People's Republic of China
| | - Tao Deng
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai, 200240, People's Republic of China
| |
Collapse
|
25
|
Abstract
Electron microscopy of biological cells in liquid provides unique nanoscale information. A highly attractive idea is the capability to also study physiological processes of live cells with electron microscopy. However, this idea seems unrealistic because the minimal needed electron dose to obtain contrast is already many orders of magnitude above the lethal dose known to cause reproductive-cell death. We show here that claims of electron microscopy of viable cells in recent reports are based on a questionable interpretation of the used fluorescence live/dead assay. A practical alternative to study biological processes is correlative light and electron microscopy.
Collapse
Affiliation(s)
| | - Diana B Peckys
- Department of Biophysics, Saarland University , D-66421 Homburg/Saar, Germany
| |
Collapse
|
26
|
Hermannsdörfer J, Tinnemann V, Peckys DB, de Jonge N. The Effect of Electron Beam Irradiation in Environmental Scanning Transmission Electron Microscopy of Whole Cells in Liquid. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2016; 22:656-665. [PMID: 27137077 DOI: 10.1017/s1431927616000763] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Whole cells can be studied in their native liquid environment using electron microscopy, and unique information about the locations and stoichiometry of individual membrane proteins can be obtained from many cells thus taking cell heterogeneity into account. Of key importance for the further development of this microscopy technology is knowledge about the effect of electron beam radiation on the samples under investigation. We used environmental scanning electron microscopy (ESEM) with scanning transmission electron microscopy (STEM) detection to examine the effect of radiation for whole fixed COS7 fibroblasts in liquid. The main observation was the localization of nanoparticle labels attached to epidermal growth factor receptors (EGFRs). It was found that the relative distances between the labels remained mostly unchanged (<1.5%) for electron doses ranging from the undamaged native state at 10 e-/Å2 toward 103 e-/Å2. This dose range was sufficient to determine the EGFR locations with nanometer resolution and to distinguish between monomers and dimers. Various different forms of radiation damage became visible at higher doses, including severe dislocation, and the dissolution of labels.
Collapse
Affiliation(s)
| | - Verena Tinnemann
- 1INM - Leibniz Institute for New Materials,66123 Saarbrücken,Germany
| | - Diana B Peckys
- 2Department of Biophysics,Saarland University,66421 Homburg/Saar,Germany
| | - Niels de Jonge
- 1INM - Leibniz Institute for New Materials,66123 Saarbrücken,Germany
| |
Collapse
|
27
|
Kennedy E, Nelson EM, Tanaka T, Damiano J, Timp G. Live Bacterial Physiology Visualized with 5 nm Resolution Using Scanning Transmission Electron Microscopy. ACS NANO 2016; 10:2669-2677. [PMID: 26811950 DOI: 10.1021/acsnano.5b07697] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
It is now possible to visualize at nanometer resolution the infection of a living biological cell with virus without compromising cell viability using scanning transmission electron microscopy (STEM). To provide contrast while preserving viability, Escherichia coli and P1 bacteriophages were first positively stained with a very low concentration of uranyl acetate in minimal phosphate medium and then imaged with low-dose STEM in a microfluidic liquid flow cell. Under these conditions, it was established that the median lethal dose of electrons required to kill half the tested population was LD50 = 30 e(-)/nm(2), which coincides with the disruption of a wet biological membrane, according to prior reports. Consistent with the lateral resolution and high-contrast signal-to-noise ratio (SNR) inferred from Monte Carlo simulations, images of the E. coli membrane, flagella, and the bacteriophages were acquired with 5 nm resolution, but the cumulative dose exceeded LD50. On the other hand, with a cumulative dose below LD50 (and lower SNR), it was still possible to visualize the infection of E. coli by P1, showing the insertion of viral DNA within 3 s, with 5 nm resolution.
Collapse
Affiliation(s)
| | | | | | - John Damiano
- Protochips, Inc. , Morrisville, North Carolina 27560, United States
| | | |
Collapse
|
28
|
Dynamic nano-imaging of label-free living cells using electron beam excitation-assisted optical microscope. Sci Rep 2015; 5:16068. [PMID: 26525841 PMCID: PMC4630636 DOI: 10.1038/srep16068] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/06/2015] [Indexed: 11/15/2022] Open
Abstract
Optical microscopes are effective tools for cellular function analysis because biological cells can be observed non-destructively and non-invasively in the living state in either water or atmosphere condition. Label-free optical imaging technique such as phase-contrast microscopy has been analysed many cellular functions, and it is essential technology for bioscience field. However, the diffraction limit of light makes it is difficult to image nano-structures in a label-free living cell, for example the endoplasmic reticulum, the Golgi body and the localization of proteins. Here we demonstrate the dynamic imaging of a label-free cell with high spatial resolution by using an electron beam excitation-assisted optical (EXA) microscope. We observed the dynamic movement of the nucleus and nano-scale granules in living cells with better than 100 nm spatial resolution and a signal-to-noise ratio (SNR) around 10. Our results contribute to the development of cellular function analysis and open up new bioscience applications.
Collapse
|
29
|
Graphene-enabled electron microscopy and correlated super-resolution microscopy of wet cells. Nat Commun 2015; 6:7384. [PMID: 26066680 PMCID: PMC4490578 DOI: 10.1038/ncomms8384] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 04/30/2015] [Indexed: 12/23/2022] Open
Abstract
The application of electron microscopy to hydrated biological samples has been limited by high-vacuum operating conditions. Traditional methods utilize harsh and laborious sample dehydration procedures, often leading to structural artefacts and creating difficulties for correlating results with high-resolution fluorescence microscopy. Here, we utilize graphene, a single-atom-thick carbon meshwork, as the thinnest possible impermeable and conductive membrane to protect animal cells from vacuum, thus enabling high-resolution electron microscopy of wet and untreated whole cells with exceptional ease. Our approach further allows for facile correlative super-resolution and electron microscopy of wet cells directly on the culturing substrate. In particular, individual cytoskeletal actin filaments are resolved in hydrated samples through electron microscopy and well correlated with super-resolution results. Preparing biological material for electron microscopy (EM) involves harsh processing steps that can poorly preserve cellular ultrastructure. Here the authors apply a single layer of graphene onto wet cells to enable direct EM using low voltage, and correlate actin filaments and mitochondria using super-resolution microscopy.
Collapse
|
30
|
Ramachandramoorthy R, Bernal R, Espinosa HD. Pushing the envelope of in situ transmission electron microscopy. ACS NANO 2015; 9:4675-85. [PMID: 25942405 DOI: 10.1021/acsnano.5b01391] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Recent major improvements to the transmission electron microscope (TEM) including aberration-corrected electron optics, light-element-sensitive analytical instrumentation, sample environmental control, and high-speed and sensitive direct electron detectors are becoming more widely available. When these advances are combined with in situ TEM tools, such as multimodal testing based on microelectromechanical systems, key measurements and insights on nanoscale material phenomena become possible. In particular, these advances enable metrology that allows for unprecedented correlation to quantum mechanics and the predictions of atomistic models. In this Perspective, we provide a summary of recent in situ TEM research that has leveraged these new TEM capabilities as well as an outlook of the opportunities that exist in the different areas of in situ TEM experimentation. Although these advances have improved the spatial and temporal resolution of TEM, a critical analysis of the various in situ TEM fields reveals that further progress is needed to achieve the full potential of the technology.
Collapse
Affiliation(s)
- Rajaprakash Ramachandramoorthy
- †Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, United States
- ‡Department of Theoretical and Applied Mechanics, Northwestern University, Evanston, Illinois 60208, United States
| | - Rodrigo Bernal
- †Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Horacio D Espinosa
- †Department of Mechanical Engineering, Northwestern University, Evanston, Illinois 60208, United States
- ‡Department of Theoretical and Applied Mechanics, Northwestern University, Evanston, Illinois 60208, United States
| |
Collapse
|
31
|
Liu Z, Inokuma K, Ho SH, Haan RD, Hasunuma T, van Zyl WH, Kondo A. Combined cell-surface display- and secretion-based strategies for production of cellulosic ethanol with Saccharomyces cerevisiae. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:162. [PMID: 26413161 PMCID: PMC4584016 DOI: 10.1186/s13068-015-0344-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 09/18/2015] [Indexed: 05/12/2023]
Abstract
BACKGROUND Engineering Saccharomyces cerevisiae to produce heterologous cellulases is considered as a promising strategy for production of bioethanol from lignocellulose. The production of cellulase is usually pursued by one of the two strategies: displaying enzyme on the cell surface or secreting enzyme into the medium. However, to our knowledge, the combination of the two strategies in a yeast strain has not been employed. RESULTS In this study, heterologous endoglucanase (EG) and cellobiohydrolase I (CBHI) were produced in a β-glucosidase displaying S. cerevisiae strain using cell-surface display, secretion, or a combined strategy. Strains EG-D-CBHI-D and EG-S-CBHI-S (with both enzymes displayed on the cell surface or with both enzymes secreted to the surrounding medium) showed higher ethanol production (2.9 and 2.6 g/L from 10 g/L phosphoric acid swollen cellulose, respectively), than strains EG-D-CBHI-S and EG-S-CBHI-D (with EG displayed on cell surface and CBHI secreted, or vice versa). After 3-cycle repeated-batch fermentation, the cellulose degradation ability of strain EG-D-CBHI-D remained 60 % of the 1st batch, at a level that was 1.7-fold higher than that of strain EG-S-CBHI-S. CONCLUSIONS This work demonstrated that placing EG and CBHI in the same space (on the cell surface or in the medium) was favorable for amorphous cellulose-based ethanol fermentation. In addition, the cellulolytic yeast strain that produced enzymes by the cell-surface display strategy performed better in cell-recycle batch fermentation compared to strains producing enzymes via the secretion strategy.
Collapse
Affiliation(s)
- Zhuo Liu
- />Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
| | - Kentaro Inokuma
- />Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
| | - Shih-Hsin Ho
- />Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
- />State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, 150090 People’s Republic of China
| | - Riaan den Haan
- />Department of Biotechnology, University of the Western Cape, Bellville, 7530 South Africa
| | - Tomohisa Hasunuma
- />Organization of Advanced Science and Technology, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
| | - Willem H. van Zyl
- />Department of Microbiology, University of Stellenbosch, Stellenbosch, 7600 South Africa
| | - Akihiko Kondo
- />Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
- />Biomass Engineering Program, RIKEN, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| |
Collapse
|
32
|
Woehl TJ, Kashyap S, Firlar E, Perez-Gonzalez T, Faivre D, Trubitsyn D, Bazylinski DA, Prozorov T. Correlative electron and fluorescence microscopy of magnetotactic bacteria in liquid: toward in vivo imaging. Sci Rep 2014; 4:6854. [PMID: 25358460 PMCID: PMC4215306 DOI: 10.1038/srep06854] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 10/10/2014] [Indexed: 12/05/2022] Open
Abstract
Magnetotactic bacteria biomineralize ordered chains of uniform, membrane-bound magnetite or greigite nanocrystals that exhibit nearly perfect crystal structures and species-specific morphologies. Transmission electron microscopy (TEM) is a critical technique for providing information regarding the organization of cellular and magnetite structures in these microorganisms. However, conventional TEM can only be used to image air-dried or vitrified bacteria removed from their natural environment. Here we present a correlative scanning TEM (STEM) and fluorescence microscopy technique for imaging viable cells of Magnetospirillum magneticum strain AMB-1 in liquid using an in situ fluid cell TEM holder. Fluorescently labeled cells were immobilized on microchip window surfaces and visualized in a fluid cell with STEM, followed by correlative fluorescence imaging to verify their membrane integrity. Notably, the post-STEM fluorescence imaging indicated that the bacterial cell wall membrane did not sustain radiation damage during STEM imaging at low electron dose conditions. We investigated the effects of radiation damage and sample preparation on the bacteria viability and found that approximately 50% of the bacterial membranes remained intact after an hour in the fluid cell, decreasing to ~30% after two hours. These results represent a first step toward in vivo studies of magnetite biomineralization in magnetotactic bacteria.
Collapse
Affiliation(s)
- Taylor J. Woehl
- Emergent Atomic and Magnetic Structures, Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA 50011, USA
| | - Sanjay Kashyap
- Emergent Atomic and Magnetic Structures, Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA 50011, USA
| | - Emre Firlar
- Emergent Atomic and Magnetic Structures, Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA 50011, USA
| | - Teresa Perez-Gonzalez
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Damien Faivre
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Denis Trubitsyn
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV 89154, USA
| | - Dennis A. Bazylinski
- School of Life Sciences, University of Nevada at Las Vegas, Las Vegas, NV 89154, USA
| | - Tanya Prozorov
- Emergent Atomic and Magnetic Structures, Division of Materials Sciences and Engineering, Ames Laboratory, Ames, IA 50011, USA
| |
Collapse
|
33
|
Peckys DB, de Jonge N. Liquid scanning transmission electron microscopy: imaging protein complexes in their native environment in whole eukaryotic cells. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:346-65. [PMID: 24548636 DOI: 10.1017/s1431927614000099] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Scanning transmission electron microscopy (STEM) of specimens in liquid, so-called Liquid STEM, is capable of imaging the individual subunits of macromolecular complexes in whole eukaryotic cells in liquid. This paper discusses this new microscopy modality within the context of state-of-the-art microscopy of cells. The principle of operation and equations for the resolution are described. The obtained images are different from those acquired with standard transmission electron microscopy showing the cellular ultrastructure. Instead, contrast is obtained on specific labels. Images can be recorded in two ways, either via STEM at 200 keV electron beam energy using a microfluidic chamber enclosing the cells, or via environmental scanning electron microscopy at 30 keV of cells in a wet environment. The first series of experiments involved the epidermal growth factor receptor labeled with gold nanoparticles. The labels were imaged in whole fixed cells with nanometer resolution. Since the cells can be kept alive in the microfluidic chamber, it is also feasible to detect the labels in unfixed, live cells. The rapid sample preparation and imaging allows studies of multiple whole cells.
Collapse
Affiliation(s)
- Diana B Peckys
- 1 Leibniz Institute for New Materials (INM), 66123 Saarbrücken, Germany
| | - Niels de Jonge
- 1 Leibniz Institute for New Materials (INM), 66123 Saarbrücken, Germany
| |
Collapse
|
34
|
Fungicidal mechanisms of cathelicidins LL-37 and CATH-2 revealed by live-cell imaging. Antimicrob Agents Chemother 2014; 58:2240-8. [PMID: 24492359 DOI: 10.1128/aac.01670-13] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antifungal mechanisms of action of two cathelicidins, chicken CATH-2 and human LL-37, were studied and compared with the mode of action of the salivary peptide histatin 5 (Hst5). Candida albicans was used as a model organism for fungal pathogens. Analysis by live-cell imaging showed that the peptides kill C. albicans rapidly. CATH-2 is the most active peptide and kills C. albicans within 5 min. Both cathelicidins induce cell membrane permeabilization and simultaneous vacuolar expansion. Minimal fungicidal concentrations (MFC) are in the same order of magnitude for all three peptides, but the mechanisms of antifungal activity are very different. The activity of cathelicidins is independent of the energy status of the fungal cell, unlike Hst5 activity. Live-cell imaging using fluorescently labeled peptides showed that both CATH-2 and LL-37 quickly localize to the C. albicans cell membrane, while Hst5 was mainly directed to the fungal vacuole. Small amounts of cathelicidins internalize at sub-MFCs, suggesting that intracellular activities of the peptide could contribute to the antifungal activity. Analysis by flow cytometry indicated that CATH-2 significantly decreases C. albicans cell size. Finally, electron microscopy showed that CATH-2 affects the integrity of the cell membrane and nuclear envelope. It is concluded that the general mechanisms of action of both cathelicidins are partially similar (but very different from that of Hst5). CATH-2 has unique features and possesses antifungal potential superior to that of LL-37.
Collapse
|
35
|
Nawa Y, Inami W, Lin S, Kawata Y, Terakawa S, Fang CY, Chang HC. Multi-color imaging of fluorescent nanodiamonds in living HeLa cells using direct electron-beam excitation. Chemphyschem 2014; 15:721-6. [PMID: 24403210 DOI: 10.1002/cphc.201300802] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 11/11/2013] [Indexed: 01/28/2023]
Abstract
Multi-color, high spatial resolution imaging of fluorescent nanodiamonds (FNDs) in living HeLa cells has been performed with a direct electron-beam excitation-assisted fluorescence (D-EXA) microscope. In this technique, fluorescent materials are directly excited with a focused electron beam and the resulting cathodoluminescence (CL) is detected with nanoscale resolution. Green- and red-light-emitting FNDs were employed for two-color imaging, which were observed simultaneously in the cells with high spatial resolution. This technique could be applied generally for multi-color immunostaining to reveal various cell functions.
Collapse
Affiliation(s)
- Yasunori Nawa
- Graduate School of Science and Technology, Shizuoka University, Johoku, Naka, Hamamatsu 4328561 (Japan), Fax: (+81) 53-471-1128; Research Fellow of the Japan Society for the Promotion of Science, Chiyoda, Tokyo 1020083 (Japan)
| | | | | | | | | | | | | |
Collapse
|
36
|
Peckys DB, Dukes MJ, de Jonge N. Correlative fluorescence and electron microscopy of quantum dot labeled proteins on whole cells in liquid. Methods Mol Biol 2014; 1117:527-40. [PMID: 24357378 DOI: 10.1007/978-1-62703-776-1_23] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Correlative fluorescence microscopy and scanning transmission electron microscopy (STEM) of cells fully immersed in liquid is a new methodology with many application areas. Proteins, in live cells immobilized on microchips, are labeled with fluorescent quantum dot (QD) nanoparticles. In this protocol, the epidermal growth factor receptor (EGFR) is labeled. The cells are fixed after a selected labeling time, for example, 5 min as needed to form EGFR dimers. The microchip with cells is then imaged with fluorescence microscopy. Thereafter, the microchip with the labeled cells and one with a spacer are assembled in a special microfluidic device and imaged with STEM.
Collapse
Affiliation(s)
- Diana B Peckys
- INM-Leibniz Institute for New Materials, Saarbrücken, Germany
| | | | | |
Collapse
|
37
|
Correlative Fluorescence and Scanning Transmission Electron Microscopy of Quantum Dot-Labeled Proteins on Whole Cells in Liquid. Methods Cell Biol 2014; 124:305-22. [DOI: 10.1016/b978-0-12-801075-4.00014-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
|
38
|
de Jonge N, Pfaff M, Peckys DB. Practical Aspects of Transmission Electron Microscopy in Liquid. ADVANCES IN IMAGING AND ELECTRON PHYSICS 2014. [DOI: 10.1016/b978-0-12-800264-3.00001-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
|
39
|
Miyazaki HT, Kasaya T, Takemura T, Hanagata N, Yasuda T, Miyazaki H. Diffraction-unlimited optical imaging of unstained living cells in liquid by electron beam scanning of luminescent environmental cells. OPTICS EXPRESS 2013; 21:28198-28218. [PMID: 24514332 DOI: 10.1364/oe.21.028198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
An environmental cell with a 50-nm-thick cathodoluminescent window was attached to a scanning electron microscope, and diffraction-unlimited near-field optical imaging of unstained living human lung epithelial cells in liquid was demonstrated. Electrons with energies as low as 0.8 - 1.2 kV are sufficiently blocked by the window without damaging the specimens, and form a sub-wavelength-sized illumination light source. A super-resolved optical image of the specimen adhered to the opposite window surface was acquired by a photomultiplier tube placed below. The cells after the observation were proved to stay alive. The image was formed by enhanced dipole radiation or energy transfer, and features as small as 62 nm were resolved.
Collapse
|
40
|
Abstract
The biological processes occurring in a cell are complex and dynamic, and to achieve a comprehensive understanding of the molecular mechanisms underlying these processes, both temporal and spatial information is required. While cryo-electron tomography (cryoET) provides three-dimensional (3D) still pictures of near-native state cells and organelles at molecular resolution, fluorescence light microscopy (fLM) offers movies of dynamic cellular processes in living cells. Combining and integrating these two commonly used imaging modalities (termed correlative microscopy) provides a powerful means to not only expand the imaging scale and resolution but also to complement the dynamic information available from optical microscopy with the molecular-level, 3D ultrastructure detail provided by cryoET. As such, a correlative approach performed on a given specimen can provide high resolution snapshots of dynamic cellular events. In this article, I review recent advances in correlative light microscopy and cryoET and discuss major findings made available by applying this method.
Collapse
Affiliation(s)
- Peijun Zhang
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA.
| |
Collapse
|
41
|
Chen Q, Smith JM, Park J, Kim K, Ho D, Rasool HI, Zettl A, Alivisatos AP. 3D motion of DNA-Au nanoconjugates in graphene liquid cell electron microscopy. NANO LETTERS 2013; 13:4556-61. [PMID: 23944844 DOI: 10.1021/nl402694n] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Liquid-phase transmission electron microscopy (TEM) can probe and visualize dynamic events with structural or functional details at the nanoscale in a liquid medium. Earlier efforts have focused on the growth and transformation kinetics of hard material systems, relying on their stability under electron beam. Our recently developed graphene liquid cell technique pushed the spatial resolution of such imaging to the atomic scale but still focused on growth trajectories of metallic nanocrystals. Here, we adopt this technique to imaging three-dimensional (3D) dynamics of soft materials instead, double strand (dsDNA) connecting Au nanocrystals as one example, at nanometer resolution. We demonstrate first that a graphene liquid cell can seal an aqueous sample solution of a lower vapor pressure than previously investigated well against the high vacuum in TEM. Then, from quantitative analysis of real time nanocrystal trajectories, we show that the status and configuration of dsDNA dictate the motions of linked nanocrystals throughout the imaging time of minutes. This sustained connecting ability of dsDNA enables this unprecedented continuous imaging of its dynamics via TEM. Furthermore, the inert graphene surface minimizes sample-substrate interaction and allows the whole nanostructure to rotate freely in the liquid environment; we thus develop and implement the reconstruction of 3D configuration and motions of the nanostructure from the series of 2D projected TEM images captured while it rotates. In addition to further proving the nanoconjugate structural stability, this reconstruction demonstrates 3D dynamic imaging by TEM beyond its conventional use in seeing a flattened and dry sample. Altogether, we foresee the new and exciting use of graphene liquid cell TEM in imaging 3D biomolecular transformations or interaction dynamics at nanometer resolution.
Collapse
Affiliation(s)
- Qian Chen
- Department of Chemistry, ∥Miller Institute for Basic Research in Science, and §Department of Physics, University of California , Berkeley, California 94720, United States
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Correlative cryo-electron tomography and optical microscopy of cells. Curr Opin Struct Biol 2013; 23:763-70. [PMID: 23962486 DOI: 10.1016/j.sbi.2013.07.017] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/02/2013] [Accepted: 07/28/2013] [Indexed: 12/11/2022]
Abstract
The biological processes occurring in a cell are complex and dynamic, and to achieve a comprehensive understanding of the molecular mechanisms underlying these processes, both temporal and spatial information is required. While cryo-electron tomography (cryoET) provides three-dimensional (3D) still pictures of near-native state cells and organelles at molecular resolution, fluorescence light microscopy (fLM) offers movies of dynamic cellular processes in living cells. Combining and integrating these two commonly used imaging modalities (termed correlative microscopy) provides a powerful means to not only expand the imaging scale and resolution but also to complement the dynamic information available from optical microscopy with the molecular-level, 3D ultrastructure detail provided by cryoET. As such, a correlative approach performed on a given specimen can provide high resolution snapshots of dynamic cellular events. In this article, I review recent advances in correlative light microscopy and cryoET and discuss major findings made available by applying this method.
Collapse
|
43
|
Tihlaříková E, Neděla V, Shiojiri M. In situ study of live specimens in an environmental scanning electron microscope. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2013; 19:914-918. [PMID: 23635483 DOI: 10.1017/s1431927613000603] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this paper we introduce new methodology for the observation of living biological samples in an environmental scanning electron microscope (ESEM). The methodology is based on an unconventional initiation procedure for ESEM chamber pumping, free from purge-flood cycles, and on the ability to control thermodynamic processes close to the sample. The gradual and gentle change of the working environment from air to water vapor enables the study of not only living samples in dynamic in situ experiments and their manifestation of life (sample walking) but also its experimentally stimulated physiological reactions. Moreover, Monte Carlo simulations of primary electron beam energy losses in a water layer on the sample surface were studied; consequently, the influence of the water thickness on radiation, temperature, or chemical damage of the sample was considered.
Collapse
Affiliation(s)
- Eva Tihlaříková
- Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, Brno 612 64, Czech Republic
| | | | | |
Collapse
|
44
|
Bubner P, Plank H, Nidetzky B. Visualizing cellulase activity. Biotechnol Bioeng 2013; 110:1529-49. [DOI: 10.1002/bit.24884] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 01/08/2013] [Accepted: 02/22/2013] [Indexed: 11/08/2022]
|
45
|
Sousa AA, Leapman RD. Development and application of STEM for the biological sciences. Ultramicroscopy 2012; 123:38-49. [PMID: 22749213 PMCID: PMC3500455 DOI: 10.1016/j.ultramic.2012.04.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 04/06/2012] [Accepted: 04/13/2012] [Indexed: 01/06/2023]
Abstract
The design of the scanning transmission electron microscope (STEM), as conceived originally by Crewe and coworkers, enables the highly efficient and flexible collection of different elastic and inelastic signals resulting from the interaction of a focused probe of incident electrons with a specimen. In the present paper we provide a brief review for how the STEM today can be applied towards a range of different problems in the biological sciences, emphasizing four main areas of application. (1) For three decades, the most widely used STEM technique has been the mass determination of proteins and other macromolecular assemblies. Such measurements can be performed at low electron dose by collecting the high-angle dark-field signal using an annular detector. STEM mass mapping has proven valuable for characterizing large protein assemblies such as filamentous proteins with a well-defined mass per length. (2) The annular dark-field signal can also be used to image ultrasmall, functionalized nanoparticles of heavy atoms for labeling specific amino-acid sequences in protein assemblies. (3) By acquiring electron energy loss spectra (EELS) at each pixel in a hyperspectral image, it is possible to map the distributions of specific bound elements like phosphorus, calcium and iron in isolated macromolecular assemblies or in compartments within sectioned cells. Near single atom sensitivity is feasible provided that the specimen can tolerate a very high incident electron dose. (4) Electron tomography is a new application of STEM that enables three-dimensional reconstruction of micrometer-thick sections of cells. In this technique a probe of small convergence angle gives a large depth of field throughout the thickness of the specimen while maintaining a probe diameter of <2 nm; and the use of an on-axis bright-field detector reduces the effects of beam broadening and thus improves the spatial resolution compared to that attainable by STEM dark-field tomography.
Collapse
Affiliation(s)
- Alioscka A. Sousa
- National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Richard D. Leapman
- National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
46
|
Evans JE, Jungjohann KL, Wong PC, Chiu PL, Dutrow GH, Arslan I, Browning ND. Visualizing macromolecular complexes with in situ liquid scanning transmission electron microscopy. Micron 2012; 43:1085-90. [PMID: 22386621 PMCID: PMC9979698 DOI: 10.1016/j.micron.2012.01.018] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 01/30/2012] [Accepted: 01/31/2012] [Indexed: 11/25/2022]
Abstract
A central focus of biological research is understanding the structure/function relationship of macromolecular protein complexes. Yet conventional transmission electron microscopy techniques are limited to static observations. Here we present the first direct images of purified macromolecular protein complexes using in situ liquid scanning transmission electron microscopy. Our results establish the capability of this technique for visualizing the interface between biology and nanotechnology with high fidelity while also probing the interactions of biomolecules within solution. This method represents an important advancement towards allowing future high-resolution observations of biological processes and conformational dynamics in real-time.
Collapse
Affiliation(s)
- James E. Evans
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, United States,Pacific Northwest National Laboratory, 3335 Q Avenue, Richland, WA 99354, United States,Corresponding author. (J.E. Evans)
| | - Katherine L. Jungjohann
- Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, CA 95616, United States
| | - Peony C.K. Wong
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, United States
| | - Po-Lin Chiu
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, United States
| | - Gavin H. Dutrow
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, United States
| | - Ilke Arslan
- Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, CA 95616, United States,Pacific Northwest National Laboratory, 3335 Q Avenue, Richland, WA 99354, United States
| | - Nigel D. Browning
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, United States,Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, CA 95616, United States,Pacific Northwest National Laboratory, 3335 Q Avenue, Richland, WA 99354, United States
| |
Collapse
|
47
|
Abstract
Imaging samples in liquids with electron microscopy can provide unique insights into biological systems, such as cells containing labelled proteins, and into processes of importance in materials science, such as nanoparticle synthesis and electrochemical deposition. Here we review recent progress in the use of electron microscopy in liquids and its applications. We examine the experimental challenges involved and the resolution that can be achieved with different forms of the technique. We conclude by assessing the potential role that electron microscopy of liquid samples can play in areas such as energy storage and bioimaging.
Collapse
Affiliation(s)
- Niels de Jonge
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, Tennessee 37232, USA
| | | |
Collapse
|
48
|
Imaging Specific Protein Labels on Eukaryotic Cells in Liquid with Scanning Transmission Electron Microscopy. ACTA ACUST UNITED AC 2011. [DOI: 10.1017/s1551929511000903] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Understanding the structure and dynamics of the protein complexes that underlie cellular function is a central scientific challenge. Biochemical techniques used to identify such complexes would be enhanced by the imaging of specific molecular positions in the context of intact cells, with protein-scale resolution (on the order of a few nanometers). Currently, though, nanometer resolution can only be achieved at the cost of less-direct imaging of the unperturbed cell. Cellular ultrastructure is traditionally studied by transmission electron microscopy (TEM), which yields nanometer resolution on embedded and stained sections, or cryo sections. These cellular samples are neither intact nor in their native liquid state. Light microscopy is used to image protein distributions in fluorescently labeled cells in liquid to investigate cellular function, but even recent improvements in resolution by nanoscopy techniques are still insufficient to resolve the individual constituents of protein complexes. Thus, development of techniques capable of high-resolution imaging in native cellular states would contribute significantly to our understanding of cellular function at the molecular level. The development of liquid compartments that include electron-transparent silicon nitride membrane windows has led to the introduction of a novel concept to achieve nanometer resolution on tagged proteins in cells.
Collapse
|