Comparison between a low-voltage benchtop electron microscope and conventional TEM for number size distribution of nearly spherical shape constituent particles of nanomaterial powders and colloids

Dazon, Claire; Maxit, Benoît; Witschger, Olivier

doi:10.1016/j.micron.2018.09.007

Cited by 8 publications

(4 citation statements)

References 14 publications

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“…In AFM, such large NM-300K NPs were not taken into account since it was not possible to accurately determine their height because these large NPs sat on top of other NPs. Compared to our NM-300K direct technique-based average size of 16.8 ± 12.0 nm (Table 1), a recent study using traditional and tabletop TEMs provides similar values albeit with a narrower range in the NP size determination of NM-300K, 17.2 ± 5.5 nm and 19.1 ± 3.3 nm, respectively [84]. Quantification of sub-population proportions is a major challenge for metrological characterization of nanomaterials.…”

Section: Discussionsupporting

confidence: 53%

On the Operational Aspects of Measuring Nanoparticle Sizes

et al. 2018

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Nanoparticles are defined as elementary particles with a size between 1 and 100 nm for at least 50% (in number). They can be made from natural materials, or manufactured. Due to their small sizes, novel toxicological issues are raised and thus determining the accurate size of these nanoparticles is a major challenge. In this study, we performed an intercomparison experiment with the goal to measure sizes of several nanoparticles, in a first step, calibrated beads and monodispersed SiO2 Ludox®, and, in a second step, nanoparticles (NPs) of toxicological interest, such as Silver NM-300 K and PVP-coated Ag NPs, Titanium dioxide A12, P25(Degussa), and E171(A), using commonly available laboratory techniques such as transmission electron microscopy, scanning electron microscopy, small-angle X-ray scattering, dynamic light scattering, wet scanning transmission electron microscopy (and its dry state, STEM) and atomic force microscopy. With monomodal distributed NPs (polystyrene beads and SiO2 Ludox®), all tested techniques provide a global size value amplitude within 25% from each other, whereas on multimodal distributed NPs (Ag and TiO2) the inter-technique variation in size values reaches 300%. Our results highlight several pitfalls of NP size measurements such as operational aspects, which are unexpected consequences in the choice of experimental protocols. It reinforces the idea that averaging the NP size from different biophysical techniques (and experimental protocols) is more robust than focusing on repetitions of a single technique. Besides, when characterizing a heterogeneous NP in size, a size distribution is more informative than a simple average value. This work emphasizes the need for nanotoxicologists (and regulatory agencies) to test a large panel of different techniques before making a choice for the most appropriate technique(s)/protocol(s) to characterize a peculiar NP.

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Section: Discussionsupporting

confidence: 53%

On the Operational Aspects of Measuring Nanoparticle Sizes

et al. 2018

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“…Example particle-size distributions and radial-distribution functions computed from BPartIS predictions of images not present in the EMPS data set. (a) SEM of Au@SiO 2 core–shell nanoparticles by Gundanna et al reprinted from ref , Copyright (2020); (b) TEM of ERM FD 304 colloidal SiO 2 nanoparticles by Dazon et al reprinted from ref , Copyright (2019). All with permission from Elsevier.…”

Section: Resultsmentioning

confidence: 99%

Bayesian Particle Instance Segmentation for Electron Microscopy Image Quantification

Yildirim

Cole

2021

J. Chem. Inf. Model.

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Automating the analysis portion of materials characterization by electron microscopy (EM) has the potential to accelerate the process of scientific discovery. To this end, we present a Bayesian deep-learning model for semantic segmentation and localization of particle instances in EM images. These segmentations can subsequently be used to compute quantitative measures such as particle-size distributions, radial- distribution functions, average sizes, and aspect ratios of the particles in an image. Moreover, by making use of the epistemic uncertainty of our model, we obtain uncertainty estimates of its outputs and use these to filter out false-positive predictions and hence produce more accurate quantitative measures. We incorporate our method into the ImageDataExtractor package, as ImageDataExtractor 2.0, which affords a full pipeline to automatically extract particle information for large-scale data-driven materials discovery. Finally, we present and make publicly available the Electron Microscopy Particle Segmentation (EMPS) data set. This is the first human-labeled particle instance segmentation data set, consisting of 465 EM images and their corresponding semantic instance segmentation maps.

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“…The new low-voltage TEMs LVEM25/MiniTEM provide significant improvement of the imaging performance in comparison with the low-voltage desktop TEM LVEM5 which is operated at 5 kV. 10 The LVEM5 uses the same core technology than the LVEM25 and is much smaller than the LVEM25/MiniTEM, but penetration depth of the electron beam is limited to very thin samples such as nanoparticles, 18 small viruses (Michael Laue, unpublished observations), or very thin sections, 19,20 which prevents its routine usage in diagnostic EM of viruses. Although the LVEM25/MiniTEM can be used for diagnostic EM of viruses, a few features should be optimized.…”

Section: Discussionmentioning

confidence: 99%

Diagnostic Electron Microscopy of Viruses With Low-voltage Electron Microscopes

Møller

Holland

Laue

2020

J Histochem Cytochem.

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Diagnostic electron microscopy is a useful technique for the identification of viruses associated with human, animal, or plant diseases. The size of virus structures requires a high optical resolution (i.e., about 1 nm), which, for a long time, was only provided by transmission electron microscopes operated at 60 kV and above. During the last decade, low-voltage electron microscopy has been improved and potentially provides an alternative to the use of high-voltage electron microscopy for diagnostic electron microscopy of viruses. Therefore, we have compared the imaging capabilities of three low-voltage electron microscopes, a scanning electron microscope equipped with a scanning transmission detector and two low-voltage transmission electron microscopes, operated at 25 kV, with the imaging capabilities of a high-voltage transmission electron microscope using different viruses in samples prepared by negative staining and ultrathin sectioning. All of the microscopes provided sufficient optical resolution for a recognition of the viruses tested. In ultrathin sections, ultrastructural details of virus genesis could be revealed. Speed of imaging was fast enough to allow rapid screening of diagnostic samples at a reasonable throughput. In summary, the results suggest that low-voltage microscopes are a suitable alternative to high-voltage transmission electron microscopes for diagnostic electron microscopy of viruses.

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Comparison between a low-voltage benchtop electron microscope and conventional TEM for number size distribution of nearly spherical shape constituent particles of nanomaterial powders and colloids

Cited by 8 publications

References 14 publications

On the Operational Aspects of Measuring Nanoparticle Sizes

On the Operational Aspects of Measuring Nanoparticle Sizes

Bayesian Particle Instance Segmentation for Electron Microscopy Image Quantification

Diagnostic Electron Microscopy of Viruses With Low-voltage Electron Microscopes

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