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Iachina I, Brewer JR, Rubahn HG, Fiutowski J. Helium Ion Microscopy and Sectioning of Spider Silk. SCANNING 2023; 2023:2936788. [PMID: 37260614 PMCID: PMC10228223 DOI: 10.1155/2023/2936788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 06/02/2023]
Abstract
Focused ion beams have recently emerged as a powerful tool for ultrastructural imaging of biological samples. In this article, we show that helium ion microscopy (HIM), in combination with ion milling, can be used to visualize the inner structure of both major and minor ampullate silk fibers of the orb-web weaving spider Nephila madagascariensis. The internal nanofibrils were imaged in pristine silk fibers, with little or no damage to the sample structure observed. Furthermore, a method to cut/rupture the fibers using He+ ions combined with internal sample tension is presented. This showed that the stretching and rupturing of spider silk is a highly dynamic process with considerable material reorganization.
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Affiliation(s)
- Irina Iachina
- NanoSYD, Mads Clausen Institute, University of Southern Denmark, Denmark
- Department of Biochemisty and Molecular Biology, University of Southern Denmark, Denmark
| | - Jonathan R. Brewer
- Department of Biochemisty and Molecular Biology, University of Southern Denmark, Denmark
| | | | - Jacek Fiutowski
- NanoSYD, Mads Clausen Institute, University of Southern Denmark, Denmark
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2
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Schmidt M. [Not Available]. BIOSPEKTRUM : ZEITSCHRIFT DER GESELLSCHAFT FUR BIOLOGISHE CHEMIE (GBCH) UND DER VEREINIGUNG FUR ALLGEMEINE UND ANGEWANDTE MIKROBIOLOGIE (VAAM) 2022; 28:377-380. [PMID: 35698575 PMCID: PMC9178215 DOI: 10.1007/s12268-022-1772-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The past decade has seen the advent of a new imaging technique in the life sciences that is ideal for microbiological applications: the helium ion microscope (HIM). Its lateral resolution is better than one nanometre, it has a large depth-of-field and can image non-conductive specimens which renders the tool ideal for studying microbiological objects such as microbes attached to surfaces, microbial biofilms and viruses. Here we compare HIM with electron microscopy techniques and highlight selected examples that demonstrate the new possibilities for microbiology opened up by this technique.
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Affiliation(s)
- Matthias Schmidt
- ProVIS - Zentrum für Chemische Mikroskopie Abteilung Isotopen Biogeochemie Helmholtz-Zentrum für Umweltforschung GmbH - UFZ, Permoserstraße 15, D-04318 Leipzig, Deutschland
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3
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Edgar RH, Samson A, Cook J, Douglas M, Urish K, Kellum J, Hempel J, Viator JA. Photoacoustic discrimination of antibiotic-resistant and sensitive Staphylococcus aureus isolates. Lasers Surg Med 2022; 54:418-425. [PMID: 34940986 PMCID: PMC8940674 DOI: 10.1002/lsm.23487] [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: 02/08/2021] [Revised: 10/28/2021] [Accepted: 10/28/2021] [Indexed: 11/08/2022]
Abstract
OBJECTIVES Bacteremia is a serious and potentially lethal condition. Staphylococcus aureus is a leading cause of bacteremia and methicillin-resistant S. aureus (MRSA) accounts for more than a third of the cases. Compared to methicillin-sensitive S. aureus, MRSA is more than twice as likely to be fatal. Furthermore, subpopulations of seemingly isogenic bacteria may exhibit a range of susceptibilities, often called heterogenous resistance. These heterogeneous antibiotic-resistant infections are often misdiagnosed as hospital-acquired secondary infections because there are no clinically used tests that can differentiate between homogeneous and heterogeneous antibiotic resistance. We describe the development and proof of concept of rapid bacterial identification using photoacoustic flow cytometry and labeled bacteriophages with the characterization and differentiation of heterogeneous antibiotic-resistant bacterial infections. METHODS In photoacoustic flow cytometry, pulsed laser light is delivered to a sample flowing past a focused transducer and particles that absorb laser light create an acoustic response. Optically labeled bacteriophage are added to a bacterial mixture that flows through the photoacoustic chamber. The presence of target bacteria is determined by bound labeled phage which are detected photoacoustically. Incubation of bacterial samples in the presence and absence of the antibiotic daptomycin creates a difference in bacterial cell numbers that is quantified using photoacoustic flow cytometry. RESULTS Four clinical isolates were tested in the presence and absence of daptomycin. Photoacoustic events for each isolate were recorded and compared to growth curves. Samples treated with daptomycin fell into three categories: resistant, susceptible, and heterogeneous resistant. CONCLUSIONS Here we show a method to determine the presence of bacteria as a marker for bloodstream infection level and antibiotic sensitivity in less than 4 hours. Additionally, these results show an ability to identify heterogeneous resistant strains that are often misidentified.
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Affiliation(s)
- R. H. Edgar
- Department of Bioengineering, University of Pittsburgh, 300 Technology Dr, Pittsburgh, Pennsylvania 15213
| | - A.P. Samson
- Department of Engineering, Duquesne University, 600 Forbes Avenue Pittsburgh, Pennsylvania, 15282
| | - J. Cook
- Department of Engineering, Duquesne University, 600 Forbes Avenue Pittsburgh, Pennsylvania, 15282
| | - M. Douglas
- Department of Engineering, Duquesne University, 600 Forbes Avenue Pittsburgh, Pennsylvania, 15282
| | - K. Urish
- Department of Bioengineering, University of Pittsburgh, 300 Technology Dr, Pittsburgh, Pennsylvania 15213,Department of Orthopaedic Surgery, University of Pittsburgh Medical Center,3471 Fifth Avenue, Pittsburgh, Pennsylvania 15213
| | - J. Kellum
- Department of Bioengineering, University of Pittsburgh, 300 Technology Dr, Pittsburgh, Pennsylvania 15213,Department of Critical Care Medicine, University of Pittsburgh Medical Center, 5115 Centre Ave, Pittsburgh, Pennsylvania 15232
| | - J. Hempel
- Department of Engineering, Duquesne University, 600 Forbes Avenue Pittsburgh, Pennsylvania, 15282
| | - J. A. Viator
- Department of Engineering, Duquesne University, 600 Forbes Avenue Pittsburgh, Pennsylvania, 15282,Department of Bioengineering, University of Pittsburgh, 300 Technology Dr, Pittsburgh, Pennsylvania 15213
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Turzynski V, Monsees I, Moraru C, Probst AJ. Imaging Techniques for Detecting Prokaryotic Viruses in Environmental Samples. Viruses 2021; 13:2126. [PMID: 34834933 PMCID: PMC8622608 DOI: 10.3390/v13112126] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 12/28/2022] Open
Abstract
Viruses are the most abundant biological entities on Earth with an estimate of 1031 viral particles across all ecosystems. Prokaryotic viruses-bacteriophages and archaeal viruses-influence global biogeochemical cycles by shaping microbial communities through predation, through the effect of horizontal gene transfer on the host genome evolution, and through manipulating the host cellular metabolism. Imaging techniques have played an important role in understanding the biology and lifestyle of prokaryotic viruses. Specifically, structure-resolving microscopy methods, for example, transmission electron microscopy, are commonly used for understanding viral morphology, ultrastructure, and host interaction. These methods have been applied mostly to cultivated phage-host pairs. However, recent advances in environmental genomics have demonstrated that the majority of viruses remain uncultivated, and thus microscopically uncharacterized. Although light- and structure-resolving microscopy of viruses from environmental samples is possible, quite often the link between the visualization and the genomic information of uncultivated prokaryotic viruses is missing. In this minireview, we summarize the current state of the art of imaging techniques available for characterizing viruses in environmental samples and discuss potential links between viral imaging and environmental genomics for shedding light on the morphology of uncultivated viruses and their lifestyles in Earth's ecosystems.
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Affiliation(s)
- Victoria Turzynski
- Department of Chemistry, Environmental Microbiology and Biotechnology (EMB), University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany;
| | - Indra Monsees
- Department of Chemistry, Environmental Microbiology and Biotechnology (EMB), University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany;
| | - Cristina Moraru
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26111 Oldenburg, Germany;
| | - Alexander J. Probst
- Department of Chemistry, Environmental Microbiology and Biotechnology (EMB), University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany;
- Centre of Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany
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5
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Audinot JN, Philipp P, De Castro O, Biesemeier A, Hoang QH, Wirtz T. Highest resolution chemical imaging based on secondary ion mass spectrometry performed on the helium ion microscope. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2021; 84:105901. [PMID: 34404033 DOI: 10.1088/1361-6633/ac1e32] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
This paper is a review on the combination between Helium Ion Microscopy (HIM) and Secondary Ion Mass Spectrometry (SIMS), which is a recently developed technique that is of particular relevance in the context of the quest for high-resolution high-sensitivity nano-analytical solutions. We start by giving an overview on the HIM-SIMS concept and the underlying fundamental principles of both HIM and SIMS. We then present and discuss instrumental aspects of the HIM and SIMS techniques, highlighting the advantage of the integrated HIM-SIMS instrument. We give an overview on the performance characteristics of the HIM-SIMS technique, which is capable of producing elemental SIMS maps with lateral resolution below 20 nm, approaching the physical resolution limits, while maintaining a sub-nanometric resolution in the secondary electron microscopy mode. In addition, we showcase different strategies and methods allowing to take profit of both capabilities of the HIM-SIMS instrument (high-resolution imaging using secondary electrons and mass filtered secondary sons) in a correlative approach. Since its development HIM-SIMS has been successfully applied to a large variety of scientific and technological topics. Here, we will present and summarise recent applications of nanoscale imaging in materials research, life sciences and geology.
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Affiliation(s)
- Jean-Nicolas Audinot
- Advanced Instrumentation for Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - Patrick Philipp
- Advanced Instrumentation for Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - Olivier De Castro
- Advanced Instrumentation for Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - Antje Biesemeier
- Advanced Instrumentation for Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - Quang Hung Hoang
- Advanced Instrumentation for Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - Tom Wirtz
- Advanced Instrumentation for Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST), 41 rue du Brill, L-4422 Belvaux, Luxembourg
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6
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Wolff A. Is the Ne operation of the helium ion microscope suitable for electron backscatter diffraction sample preparation? BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:965-983. [PMID: 34621610 PMCID: PMC8450971 DOI: 10.3762/bjnano.12.73] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Electron backscatter diffraction (EBSD) is a powerful characterization technique which allows the study of microstructure, grain size, and orientation as well as strain of a crystallographic sample. In addition, the technique can be used for phase analysis. A mirror-flat sample surface is required for this analysis technique and different polishing approaches have been used over the years. A commonly used approach is the focused ion beam (FIB) polishing. Unfortunately, artefacts that can be easily induced by Ga FIB polishing approaches are seldom published. This work aims to provide a better understanding of the underlying causes for artefact formation and to assess if the helium ion microscope is better suited to achieve the required mirror-flat sample surface when operating the ion source with Ne instead of He. Copper was chosen as a test material and polished using Ga and Ne ions with different ion energies as well as incident angles. The results show that crystal structure alterations and, in some instances, phase transformation of Cu to Cu3Ga occurred when polishing with Ga ions. Polishing with high-energy Ne ions at a glancing angle maintains the crystal structure and significantly improves indexing in EBSD measurements. By milling down to a depth equaling the depth of the interaction volume, a steady-state condition of ion impurity concentration and number of induced defects is reached. The EBSD measurements and Monte Carlo simulations indicate that when this steady-state condition is reached more quickly, which can be achieved using high-energy Ne ions at a glancing incidence, then the overall damage to the specimen is reduced.
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Affiliation(s)
- Annalena Wolff
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, 2 George St, Brisbane 4000, QLD, Australia
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7
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Frederiksen CØ, Cohn MT, Skov LK, Schmidt EGW, Schnorr KM, Buskov S, Leppänen M, Maasilta I, Perez-Calvo E, Lopez-Ulibarri R, Klausen M. A muramidase from Acremonium alcalophilum hydrolyse peptidoglycan found in the gastrointestinal tract of broiler chickens. J Ind Microbiol Biotechnol 2021; 48:6128676. [PMID: 33693885 PMCID: PMC9113140 DOI: 10.1093/jimb/kuab008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/20/2021] [Indexed: 12/19/2022]
Abstract
This study evaluates peptidoglycan hydrolysis by a microbial muramidase from the
fungus Acremonium alcalophilum in vitro and in the
gastrointestinal tract of broiler chickens. Peptidoglycan used for in
vitro studies was derived from 5 gram-positive chicken gut isolate
type strains. In vitro peptidoglycan hydrolysis was studied by
three approaches: (a) helium ion microscopy to identify visual phenotypes of
hydrolysis, (b) reducing end assay to quantify solubilization of peptidoglycan
fragments, and (c) mass spectroscopy to estimate relative abundances of soluble
substrates and reaction products. Visual effects of peptidoglycan hydrolysis
could be observed by helium ion microscopy and the increase in abundance of
soluble peptidoglycan due to hydrolysis was quantified by a reducing end assay.
Mass spectroscopy confirmed the release of hydrolysis products and identified
muropeptides from the five different peptidoglycan sources. Peptidoglycan
hydrolysis in chicken crop, jejunum, and caecum samples was measured by
quantifying the total and soluble muramic acid content. A significant increase
in the proportion of the soluble muramic acid was observed in all three segments
upon inclusion of the microbial muramidase in the diet.
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Affiliation(s)
| | | | | | | | | | | | - Miika Leppänen
- Department of Biological and Environmental Sciences and Department of Physics, University of Jyvaskyla, Jyvaskyla, FI-40014, Finland
| | - Ilari Maasilta
- Department of Physics, University of Jyvaskyla, Jyvaskyla, FI-40014, Finland
| | - Estefania Perez-Calvo
- Research Centre for Animal Nutrition and Health, DSM Nutritional Products, Village-Neuf, F-68305 Saint Louis, France
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8
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Emmrich D, Wolff A, Meyerbröker N, Lindner JKN, Beyer A, Gölzhäuser A. Scanning transmission helium ion microscopy on carbon nanomembranes. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:222-231. [PMID: 33728240 PMCID: PMC7934706 DOI: 10.3762/bjnano.12.18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
A dark-field scanning transmission ion microscopy detector was designed for the helium ion microscope. The detection principle is based on a secondary electron conversion holder with an exchangeable aperture strip allowing its acceptance angle to be tuned from 3 to 98 mrad. The contrast mechanism and performance were investigated using freestanding nanometer-thin carbon membranes. The results demonstrate that the detector can be optimized either for most efficient signal collection or for maximum image contrast. The designed setup allows for the imaging of thin low-density materials that otherwise provide little signal or contrast and for a clear end-point detection in the fabrication of nanopores. In addition, the detector is able to determine the thickness of membranes with sub-nanometer precision by quantitatively evaluating the image signal and comparing the results with Monte Carlo simulations. The thickness determined by the dark-field transmission detector is compared to X-ray photoelectron spectroscopy and energy-filtered transmission electron microscopy measurements.
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Affiliation(s)
- Daniel Emmrich
- Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33615 Bielefeld, Germany
| | - Annalena Wolff
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, 2 George St, Brisbane 4000, QLD, Australia
| | | | | | - André Beyer
- Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33615 Bielefeld, Germany
| | - Armin Gölzhäuser
- Physics of Supramolecular Systems and Surfaces, Bielefeld University, 33615 Bielefeld, Germany
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9
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Frese N, Schmerer P, Wortmann M, Schürmann M, König M, Westphal M, Weber F, Sudhoff H, Gölzhäuser A. Imaging of SARS-CoV-2 infected Vero E6 cells by helium ion microscopy. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:172-179. [PMID: 33614383 PMCID: PMC7871036 DOI: 10.3762/bjnano.12.13] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 01/28/2021] [Indexed: 05/27/2023]
Abstract
Helium ion microscopy (HIM) offers the opportunity to obtain direct views of biological samples such as cellular structures, virus particles, and microbial interactions. Imaging with the HIM combines sub-nanometer resolution, large depth of field, and high surface sensitivity. Due to its charge compensation capability, the HIM can image insulating biological samples without additional conductive coatings. Here, we present an exploratory HIM study of SARS-CoV-2 infected Vero E6 cells, in which several areas of interaction between cells and virus particles, as well as among virus particles, were imaged. The HIM pictures show the three-dimensional appearance of SARS-CoV-2 and the surface of Vero E6 cells at a multiplicity of infection of approximately 1 with great morphological detail. The absence of a conductive coating allows for a distinction between virus particles bound to the cell membrane and virus particles lying on top of the membrane. After prolonged imaging, it was found that ion-induced deposition of hydrocarbons from the vacuum renders the sample sufficiently conductive to allow for imaging even without charge compensation. The presented images demonstrate the potential of the HIM in bioimaging, especially for the imaging of interactions between viruses and their host organisms.
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Affiliation(s)
- Natalie Frese
- Physics of Supramolecular Systems and Surfaces, Faculty of Physics, Bielefeld University, Bielefeld, Germany
| | - Patrick Schmerer
- Institute of Virology, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Germany
| | - Martin Wortmann
- Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, Bielefeld, Germany
| | - Matthias Schürmann
- University Clinic for Otolaryngology, Head and Neck Surgery, Medical Faculty OWL at Bielefeld University, Germany
| | - Matthias König
- Institute of Virology, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Germany
| | - Michael Westphal
- Physics of Supramolecular Systems and Surfaces, Faculty of Physics, Bielefeld University, Bielefeld, Germany
| | - Friedemann Weber
- Institute of Virology, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Germany
| | - Holger Sudhoff
- University Clinic for Otolaryngology, Head and Neck Surgery, Medical Faculty OWL at Bielefeld University, Germany
| | - Armin Gölzhäuser
- Physics of Supramolecular Systems and Surfaces, Faculty of Physics, Bielefeld University, Bielefeld, Germany
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10
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Schmidt M, Byrne JM, Maasilta IJ. Bio-imaging with the helium-ion microscope: A review. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:1-23. [PMID: 33489663 PMCID: PMC7801799 DOI: 10.3762/bjnano.12.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 11/26/2020] [Indexed: 06/01/2023]
Abstract
Scanning helium-ion microscopy (HIM) is an imaging technique with sub-nanometre resolution and is a powerful tool to resolve some of the tiniest structures in biology. In many aspects, the HIM resembles a field-emission scanning electron microscope (FE-SEM), but the use of helium ions rather than electrons provides several advantages, including higher surface sensitivity, larger depth of field, and a straightforward charge-compensating electron flood gun, which enables imaging of non-conductive samples, rendering HIM a promising high-resolution imaging technique for biological samples. Starting with studies focused on medical research, the last decade has seen some particularly spectacular high-resolution images in studies focused on plants, microbiology, virology, and geomicrobiology. However, HIM is not just an imaging technique. The ability to use the instrument for milling biological objects as small as viruses offers unique opportunities which are not possible with more conventional focused ion beams, such as gallium. Several pioneering technical developments, such as methods to couple secondary ion mass spectrometry (SIMS) or ionoluminescence with the HIM, also offer the possibility for new and exciting research on biological materials. In this review, we present a comprehensive overview of almost all currently published literature which has demonstrated the application of HIM for imaging of biological specimens. We also discuss some technical features of this unique type of instrument and highlight some of the new advances which will likely become more widely used in the years to come.
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Affiliation(s)
- Matthias Schmidt
- Helmholtz-Centre for Environmental Research GmbH - UFZ, Permoserstraße 15, 04318 Leipzig, Germany
| | - James M Byrne
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom
| | - Ilari J Maasilta
- Nanoscience Center, Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
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11
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McGenity TJ, Gessesse A, Hallsworth JE, Garcia Cela E, Verheecke‐Vaessen C, Wang F, Chavarría M, Haggblom MM, Molin S, Danchin A, Smid EJ, Lood C, Cockell CS, Whitby C, Liu S, Keller NP, Stein LY, Bordenstein SR, Lal R, Nunes OC, Gram L, Singh BK, Webster NS, Morris C, Sivinski S, Bindschedler S, Junier P, Antunes A, Baxter BK, Scavone P, Timmis K. Visualizing the invisible: class excursions to ignite children's enthusiasm for microbes. Microb Biotechnol 2020; 13:844-887. [PMID: 32406115 PMCID: PMC7264897 DOI: 10.1111/1751-7915.13576] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 03/29/2020] [Indexed: 12/15/2022] Open
Abstract
We have recently argued that, because microbes have pervasive - often vital - influences on our lives, and that therefore their roles must be taken into account in many of the decisions we face, society must become microbiology-literate, through the introduction of relevant microbiology topics in school curricula (Timmis et al. 2019. Environ Microbiol 21: 1513-1528). The current coronavirus pandemic is a stark example of why microbiology literacy is such a crucial enabler of informed policy decisions, particularly those involving preparedness of public-health systems for disease outbreaks and pandemics. However, a significant barrier to attaining widespread appreciation of microbial contributions to our well-being and that of the planet is the fact that microbes are seldom visible: most people are only peripherally aware of them, except when they fall ill with an infection. And it is disease, rather than all of the positive activities mediated by microbes, that colours public perception of 'germs' and endows them with their poor image. It is imperative to render microbes visible, to give them life and form for children (and adults), and to counter prevalent misconceptions, through exposure to imagination-capturing images of microbes and examples of their beneficial outputs, accompanied by a balanced narrative. This will engender automatic mental associations between everyday information inputs, as well as visual, olfactory and tactile experiences, on the one hand, and the responsible microbes/microbial communities, on the other hand. Such associations, in turn, will promote awareness of microbes and of the many positive and vital consequences of their actions, and facilitate and encourage incorporation of such consequences into relevant decision-making processes. While teaching microbiology topics in primary and secondary school is key to this objective, a strategic programme to expose children directly and personally to natural and managed microbial processes, and the results of their actions, through carefully planned class excursions to local venues, can be instrumental in bringing microbes to life for children and, collaterally, their families. In order to encourage the embedding of microbiology-centric class excursions in current curricula, we suggest and illustrate here some possibilities relating to the topics of food (a favourite pre-occupation of most children), agriculture (together with horticulture and aquaculture), health and medicine, the environment and biotechnology. And, although not all of the microbially relevant infrastructure will be within reach of schools, there is usually access to a market, local food store, wastewater treatment plant, farm, surface water body, etc., all of which can provide opportunities to explore microbiology in action. If children sometimes consider the present to be mundane, even boring, they are usually excited with both the past and the future so, where possible, visits to local museums (the past) and research institutions advancing knowledge frontiers (the future) are strongly recommended, as is a tapping into the natural enthusiasm of local researchers to leverage the educational value of excursions and virtual excursions. Children are also fascinated by the unknown, so, paradoxically, the invisibility of microbes makes them especially fascinating objects for visualization and exploration. In outlining some of the options for microbiology excursions, providing suggestions for discussion topics and considering their educational value, we strive to extend the vistas of current class excursions and to: (i) inspire teachers and school managers to incorporate more microbiology excursions into curricula; (ii) encourage microbiologists to support school excursions and generally get involved in bringing microbes to life for children; (iii) urge leaders of organizations (biopharma, food industries, universities, etc.) to give school outreach activities a more prominent place in their mission portfolios, and (iv) convey to policymakers the benefits of providing schools with funds, materials and flexibility for educational endeavours beyond the classroom.
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Affiliation(s)
| | - Amare Gessesse
- Department of Biological Sciences and BiotechnologyBotswana International University of Science and TechnologyPalapyeBotswana
| | - John E. Hallsworth
- Institute for Global Food SecuritySchool of Biological SciencesQueen’s University BelfastBelfastUK
| | | | | | - Fengping Wang
- School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai200240China
| | - Max Chavarría
- Escuela de QuímicaCentro de Investigaciones en Productos Naturales (CIPRONA)Universidad de Costa RicaSan JoséCosta Rica
- Centro Nacional de Innovaciones Biotecnológicas (CENIBiot)CeNAT-CONARESan JoséCosta Rica
| | - Max M. Haggblom
- Department of Biochemistry and MicrobiologyRutgers UniversityNew BrunswickNJUSA
| | - Søren Molin
- Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkLyngbyDenmark
| | - Antoine Danchin
- Institut Cochin24 rue du Faubourg Saint‐Jacques75014ParisFrance
| | - Eddy J. Smid
- Food MicrobiologyWageningen University and ResearchWageningenThe Netherlands
| | - Cédric Lood
- Department of Microbial and Molecular SystemsCentre of Microbial and Plant GeneticsLaboratory of Computational Systems BiologyKU Leuven3001LeuvenBelgium
- Department of BiosystemsLaboratory of Gene TechnologyKU Leuven3001LeuvenBelgium
| | | | | | | | - Nancy P. Keller
- Department of Medical Microbiology and ImmunologyUniversity of WisconsinMadisonWIUSA
| | - Lisa Y. Stein
- Department of Biological SciencesUniversity of AlbertaEdmontonABCanada
| | - Seth R. Bordenstein
- Department of Biological SciencesVanderbilt Microbiome InitiativeVanderbilt UniversityNashvilleTNUSA
| | - Rup Lal
- The Energy and Resources InstituteLodhi RoadNew Delhi110003India
| | - Olga C. Nunes
- Department of Chemical EngineeringUniversity of Porto4200‐465PortoPortugal
| | - Lone Gram
- Department of Biotechnology and BiomedicineTechnical University of DenmarkLyngbyDenmark
| | - Brajesh K. Singh
- Hawkesbury Institute for the EnvironmentUniversity of Western SydneyPenrithAustralia
| | - Nicole S. Webster
- Australian Institute of Marine ScienceTownsvilleQLDAustralia
- Australian Centre for EcogenomicsUniversity of QueenslandBrisbaneQLDAustralia
| | | | | | | | - Pilar Junier
- Institute of BiologyUniversity of NeuchâtelNeuchâtelSwitzerland
| | - André Antunes
- State Key Laboratory of Lunar and Planetary SciencesMacau University of Science and Technology (MUST)Taipa, Macau SARChina
| | - Bonnie K. Baxter
- Great Salt Lake InstituteWestminster CollegeSalt Lake CityUtahUSA
| | - Paola Scavone
- Department of MicrobiologyInstituto de Investigaciones Biológicas Clemente EstableMontevideoUruguay
| | - Kenneth Timmis
- Institute of MicrobiologyTechnical University of BraunschweigBraunschweigGermany
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12
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Bandara CD, Ballerin G, Leppänen M, Tesfamichael T, Ostrikov KK, Whitchurch CB. Resolving Bio-Nano Interactions of E. coli Bacteria-Dragonfly Wing Interface with Helium Ion and 3D-Structured Illumination Microscopy to Understand Bacterial Death on Nanotopography. ACS Biomater Sci Eng 2020; 6:3925-3932. [PMID: 33463326 DOI: 10.1021/acsbiomaterials.9b01973] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obtaining a comprehensive understanding of the bactericidal mechanisms of natural nanotextured surfaces is crucial for the development of fabricated nanotextured surfaces with efficient bactericidal activity. However, the scale, nature, and speed of bacteria-nanotextured surface interactions make the characterization of the interaction a challenging task. There are currently several different opinions regarding the possible mechanisms by which bacterial membrane damage occurs upon interacting with nanotextured surfaces. Advanced imaging methods could clarify this by enabling visualization of the interaction. Charged particle microscopes can achieve the required nanoscale resolution but are limited to dry samples. In contrast, light-based methods enable the characterization of living (hydrated) samples but are limited by the resolution achievable. Here we utilized both helium ion microscopy (HIM) and 3D structured illumination microscopy (3D-SIM) techniques to understand the interaction of Gram-negative bacterial membranes with nanopillars such as those found on dragonfly wings. Helium ion microscopy enables cutting and imaging at nanoscale resolution, while 3D-SIM is a super-resolution optical microscopy technique that allows visualization of live, unfixed bacteria at ∼100 nm resolution. Upon bacteria-nanopillar interaction, the energy stored due to the bending of natural nanopillars was estimated and compared with fabricated vertically aligned carbon nanotubes. With the same deflection, shorter dragonfly wing nanopillars store slightly higher energy compared to carbon nanotubes. This indicates that fabricated surfaces may achieve similar bactericidal efficiency as dragonfly wings. This study reports in situ characterization of bacteria-nanopillar interactions in real-time close to its natural state. These microscopic approaches will help further understanding of bacterial membrane interactions with nanotextured surfaces and the bactericidal mechanisms of nanotopographies so that more efficient bactericidal nanotextured surfaces can be designed and fabricated, and their bacteria-nanotopography interactions can be assessed in situ.
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Affiliation(s)
- Chaturanga D Bandara
- The ithree Institute, University of Technology Sydney, Ultimo, NSW 2007, Australia.,School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Giulia Ballerin
- The ithree Institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Miika Leppänen
- Nanoscience Center, Department of Physics, Department of Biological and Environmental Science, University of Jyvaskyla, FI-40014 Jyvaskyla, Finland
| | - Tuquabo Tesfamichael
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Kostya Ken Ostrikov
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia
| | - Cynthia B Whitchurch
- The ithree Institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
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13
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Esteban Florez FL, Trofimov AA, Ievlev A, Qian S, Rondinone AJ, Khajotia SS. Advanced characterization of surface-modified nanoparticles and nanofilled antibacterial dental adhesive resins. Sci Rep 2020; 10:9811. [PMID: 32555360 PMCID: PMC7299952 DOI: 10.1038/s41598-020-66819-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/21/2020] [Indexed: 11/30/2022] Open
Abstract
Nanotechnology can improve the performance of dental polymers. The objective of this study was to modify the surfaces of nanoparticles with silanes and proteins, characterize nanoparticles' agglomeration levels and interfaces between nanoparticles and the polymeric matrix. Undoped (n-TiO2), nitrogen-doped (N_TiO2) and nitrogen-fluorine co-doped titanium dioxide nanoparticles (NF_TiO2) were synthesized and subjected to surface modification procedures in preparation for Small-Angle X-Ray Scattering (SAXS) and Small-Angle Neutron Scattering (SANS) characterizations. Experimental adhesives were manually synthesized by incorporating 20% (v/v) of n-TiO2, N_TiO2 or NF_TiO2 (as-synthesized or surface-modified) into OptiBond Solo Plus (OPTB). Specimens (n = 15/group; d = 6.0 mm, t = 0.5 mm) of OPTB and experimental adhesives were characterized using Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS), 2-D ToF-SIMS chemical imaging and SANS. SAXS results indicated that surface-modified nanoparticles displayed higher scattering intensities in a particle-size dependent manner. ToF-SIMS results demonstrated that nanoparticles' incorporation did not adversely impact the parental polymer. 2-D ToF-SIMS chemical imaging demonstrated the distribution of Ti+ and confirmed nitrogen-doping levels. SANS results confirmed nanoparticles' functionalization and revealed the interfaces between nanoparticles and the polymer matrix. Metaloxide nanoparticles were successfully fabricated, incorporated and covalently functionalized in a commercial dental adhesive resin, thereby supporting the utilization of nanotechnology in dentistry.
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Affiliation(s)
- Fernando Luis Esteban Florez
- The University of Oklahoma Health Sciences Center, Department of Restorative Sciences, Division of Dental Biomaterials, College of Dentistry, 1201 N. Stonewall Avenue, Oklahoma City, Oklahoma, 73117, USA.
| | - Artem A Trofimov
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, Tennessee, 37831, USA
| | - Anton Ievlev
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, Tennessee, 37831, USA
| | - Shuo Qian
- Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge, Tennessee, 37831, USA
| | - Adam Justin Rondinone
- Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, Oak Ridge, Tennessee, 37831, USA
| | - Sharukh Soli Khajotia
- The University of Oklahoma Health Sciences Center, Department of Restorative Sciences, Division of Dental Biomaterials, College of Dentistry, 1201 N. Stonewall Avenue, Oklahoma City, Oklahoma, 73117, USA
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14
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Almeida GMF, Laanto E, Ashrafi R, Sundberg LR. Bacteriophage Adherence to Mucus Mediates Preventive Protection against Pathogenic Bacteria. mBio 2019; 10:e01984-19. [PMID: 31744913 PMCID: PMC6867891 DOI: 10.1128/mbio.01984-19] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/17/2019] [Indexed: 11/20/2022] Open
Abstract
Metazoans were proposed to host bacteriophages on their mucosal surfaces in a symbiotic relationship, where phages provide an external immunity against bacterial infections and the metazoans provide phages a medium for interacting with bacteria. However, scarce empirical evidence and model systems have left the phage-mucus interaction poorly understood. Here, we show that phages bind both to porcine mucus and to rainbow trout (Oncorhynchus mykiss) primary mucus, persist up to 7 days in the mucosa, and provide protection against Flavobacterium columnare Also, exposure to mucus changes the bacterial phenotype by increasing bacterial virulence and susceptibility to phage infections. This trade-off in bacterial virulence reveals ecological benefit of maintaining phages in the metazoan mucosal surfaces. Tests using other phage-bacterium pairs suggest that phage binding to mucus may be widespread in the biosphere, indicating its importance for disease, ecology, and evolution. This phenomenon may have significant potential to be exploited in preventive phage therapy.IMPORTANCE The mucosal surfaces of animals are habitat for microbes, including viruses. Bacteriophages-viruses that infect bacteria-were shown to be able to bind to mucus. This may result in a symbiotic relationship in which phages find bacterial hosts to infect, protecting the mucus-producing animal from bacterial infections in the process. Here, we studied phage binding on mucus and the effect of mucin on phage-bacterium interactions. The significance of our research is in showing that phage adhesion to mucus results in preventive protection against bacterial infections, which will serve as basis for the development of prophylactic phage therapy approaches. Besides, we also reveal that exposure to mucus upregulates bacterial virulence and that this is exploited by phages for infection, adding one additional layer to the metazoan-bacterium-phage biological interactions and ecology. This phenomenon might be widespread in the biosphere and thus crucial for understanding mucosal diseases, their outcome and treatment.
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Affiliation(s)
- Gabriel M F Almeida
- Department of Biological and Environmental Science, University of Jyvaskyla, Jyvaskyla, Finland
- Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
| | - Elina Laanto
- Department of Biological and Environmental Science, University of Jyvaskyla, Jyvaskyla, Finland
- Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Roghaieh Ashrafi
- Department of Biological and Environmental Science, University of Jyvaskyla, Jyvaskyla, Finland
- Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
| | - Lotta-Riina Sundberg
- Department of Biological and Environmental Science, University of Jyvaskyla, Jyvaskyla, Finland
- Nanoscience Center, University of Jyvaskyla, Jyvaskyla, Finland
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15
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Edgar RH, Cook J, Noel C, Minard A, Sajewski A, Fitzpatrick M, Fernandez R, Hempel JD, Kellum JA, Viator JA. Bacteriophage-mediated identification of bacteria using photoacoustic flow cytometry. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-7. [PMID: 31758676 PMCID: PMC6874036 DOI: 10.1117/1.jbo.24.11.115003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 11/04/2019] [Indexed: 05/26/2023]
Abstract
Infection with resistant bacteria has become an ever increasing problem in modern medical practice. Currently, broad spectrum antibiotics are prescribed until bacteria can be identified through blood cultures, a process that can take two to three days and is unable to provide quantitative information. To detect and quantify bacteria rapidly in blood samples, we designed a method using labeled bacteriophage in conjunction with photoacoustic flow cytometry (PAFC). PAFC is the generation of ultrasonic waves created by the absorption of laser light in particles under flow. Bacteriophage is a virus that infects bacteria and possesses the ability to discriminate bacterial surface antigens, allowing the bacteriophage to bind only to their target bacteria. Bacteria can be tagged with dyed phage and processed through a photoacoustic flow cytometer where they are detected by the acoustic response. We demonstrate that E. coli; can be detected and discriminated from Salmonella; using this method. Our goal is to develop a method to determine bacterial content in blood samples. We hope to develop this technology into future clinical use and decrease the time required to identify bacterial species from 3 to 4 days to less than 1 hour.
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Affiliation(s)
- Robert H. Edgar
- University of Pittsburgh, Swanson School of Engineering, Department of Bioengineering, Pittsburgh, Pennsylvania, United States
| | - Justin Cook
- Duquesne University, Pittsburgh, Pennsylvania, United States
| | - Cierra Noel
- Duquesne University, Pittsburgh, Pennsylvania, United States
| | - Austin Minard
- Duquesne University, Pittsburgh, Pennsylvania, United States
| | - Andrea Sajewski
- Duquesne University, Pittsburgh, Pennsylvania, United States
| | | | | | - John D. Hempel
- Duquesne University, Pittsburgh, Pennsylvania, United States
| | - John A. Kellum
- University of Pittsburgh, Center for Critical Care Nephrology, Department of Critical Care Medicine, Pittsburgh, Pennsylvania, United States
| | - John A. Viator
- University of Pittsburgh, Swanson School of Engineering, Department of Bioengineering, Pittsburgh, Pennsylvania, United States
- Duquesne University, Pittsburgh, Pennsylvania, United States
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16
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Wirtz T, De Castro O, Audinot JN, Philipp P. Imaging and Analytics on the Helium Ion Microscope. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2019; 12:523-543. [PMID: 30699036 DOI: 10.1146/annurev-anchem-061318-115457] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The helium ion microscope (HIM) has emerged as an instrument of choice for patterning, imaging and, more recently, analytics at the nanoscale. Here, we review secondary electron imaging on the HIM and the various methodologies and hardware components that have been developed to confer analytical capabilities to the HIM. Secondary electron-based imaging can be performed at resolutions down to 0.5 nm with high contrast, with high depth of field, and directly on insulating samples. Analytical methods include secondary electron hyperspectral imaging (SEHI), scanning transmission ion microscopy (STIM), backscattering spectrometry and, in particular, secondary ion mass spectrometry (SIMS). The SIMS system that was specifically designed for the HIM allows the detection of all elements, the differentiation between isotopes, and the detection of trace elements. It provides mass spectra, depth profiles, and 2D or 3D images with lateral resolutions down to 10 nm.
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Affiliation(s)
- Tom Wirtz
- Advanced Instrumentation for Ion Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST), L-4422 Belvaux, Luxembourg;
| | - Olivier De Castro
- Advanced Instrumentation for Ion Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST), L-4422 Belvaux, Luxembourg;
| | - Jean-Nicolas Audinot
- Advanced Instrumentation for Ion Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST), L-4422 Belvaux, Luxembourg;
| | - Patrick Philipp
- Advanced Instrumentation for Ion Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST), L-4422 Belvaux, Luxembourg;
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17
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Said N, Chatzinotas A, Schmidt M. Have an Ion on It: The Life-Cycle of Bdellovibrio bacteriovorus Viewed by Helium-Ion Microscopy. ACTA ACUST UNITED AC 2018; 3:e1800250. [PMID: 32627346 DOI: 10.1002/adbi.201800250] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/11/2018] [Indexed: 11/12/2022]
Abstract
Helium-ion microscopy (HIM) has so far rarely been employed to image microbial interactions. Here, the visualization of the life-cycle of the bacterial predator Bdellovibrio bacteriovorus HD100 with Escherichia coli and Pseudomonas putida, respectively, as prey is presented. The predator is brought in contact with prey and samples are taken at selected times. The system is monitored by phase-contrast microscopy and HIM. For HIM imaging, a sample preparation protocol is established that preserves the structure of Bdellovibrio, prey, and bdelloplasts. The micrographs show the attachment of the predator to its prey, the evolution of bdelloplasts, their lysis, and the release of predator progeny. The combination of HIM with two more approaches allows for investigating predator-prey interactions from different angles: First, phase-contrast micrographs provide quantitative information for the numbers of predator, prey, and bdelloplasts. Second, a numerical model solving the retarded differential equations that describe the system's time-evolution is developed and fits the experimentally determined cell numbers. In conclusion, the high resolution, the large depth of focus, and surface sensitivity of HIM hold promise to expand future studies on so far neglected ecological interactions within the microbial food web, in particular in samples with pronounced topography such as bacterial biofilms.
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Affiliation(s)
- Nedal Said
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Antonis Chatzinotas
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103, Leipzig, Germany
| | - Matthias Schmidt
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany
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