Bright-field TEM imaging of single molecules: Dream or near future?

Malac, Marek; Beleggia, Marco; Egerton, R.F.; Zhu, Yimei

doi:10.1016/j.ultramic.2006.05.001

Cited by 17 publications

(13 citation statements)

References 32 publications

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“…59 In addition to the concept of "critical dose" previously considered in the literature, our approach attributes configurational 094110-5 = 0.14 nm, as described in the text. Under the 200 keV e-beam, the signal-to-noise ratio is close to the critical value of 5 during the whole transformation process due to the large values of cross sections for a damage event.…”

Section: Resultsmentioning

confidence: 99%

Inclusion of radiation damage dynamics in high-resolution transmission electron microscopy image simulations: The example of graphene

et al. 2013

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Computer image simulations provide a crucial aid to high-resolution transmission electron microscopy (HRTEM) in gaining fundamental understanding of the structure of materials. Interpretation of HRTEM images is, however, complicated due to continuous structure deformation caused by the imaging electron beam. A computational methodology has been implemented that takes into account the effects of the electron beam on deformation of sample structure during observation and imaging in HRTEM. The evolution of the sample structure is described as a sequence of externally initiated discrete damage events with a frequency determined by the cross section, which depends on the energy of the electron beam. A series of images showing structure evolution with time is obtained by coupling molecular dynamics simulations with the image simulation. These simulation parts are linked by two experimental parameters: the energy of the electron beam and the electron dose rate. As the energy of the electron beam also determines resolution and contrast of the obtained HRTEM image, a careful selection of its value is required to achieve a fine balance between reduction of the sample damage caused by the electron beam and the quality of the acquired image. The proposed computational approach is used to simulate the recently observed process of structural transformation of a small graphene flake into a fullerene cage. The simulated series of images showing the evolution of a graphene flake under the 80 keV electron beam closely reproduces experimental HRTEM images with regard to the structure evolution route, evolution rate, and signal-to-noise ratio. We show that under the increased electron beam energy of 200 keV a similar observation will be obscured by high damage rate or low signal-to-noise ratio.

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Section: Resultsmentioning

confidence: 99%

Inclusion of radiation damage dynamics in high-resolution transmission electron microscopy image simulations: The example of graphene

et al. 2013

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“…Outside the context of the living cell there is already a burgeoning interest in studies of single biomolecules which have been realized in various ways including, for example, the use of spectroscopic, X-ray, and neutron scattering and scanning probe and electron microscopy techniques. [9][10][11][12][13][14][15][16][17][18] In particular, recent advances in functionalizing nanoparticles with complex macromolecules 19,20 provide completely new opportunities of single molecule tagging and tracing. The most significant previous research in this area has focused on bioconjugates between DNA and gold nanoparticles, prepared using well-established gold-thiol chemistry.…”

Section: Introductionmentioning

confidence: 99%

Enzymatic Activity of Lipase−Nanoparticle Conjugates and the Digestion of Lipid Liquid Crystalline Assemblies

Brennan¹,

Kanaras²,

Nativo³

et al. 2010

Langmuir

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Variants of lipase were attached to gold nanoparticles (NPs) and their enzymatic activity was studied. The two bioengineered lipase variants have been prepared with biotin groups attached to different residues on the protein outer surface. The biotinylation was evidenced by denaturing polyacrylamide gel electrophoresis and quantified by the ([2-(4'-hydroxyazobenzene)]benzoic acid spectrophotometric test. NPs of 14 +/- 1 nm diameter coated with thiolated-polyethylene glycol ligands containing controlled proportions of biotin moieties have been prepared and characterized by transmission electron microscopy, UV-vis spectroscopy, small angle neutron scattering, and elemental analysis. These biotin-functionalized NPs were conjugated to lipase using streptavidin as a linker molecule. Enzyme activity assays on the lipase-nanoparticle conjugates show that the lipase loading and activity of the NPs can be controlled by varying the percentage of biotin groups in the particle protecting coat. The lipase-NP conjugates prepared using one variant display higher activity than those prepared using the other variant, demonstrating orientation-dependent enzyme activity. Cryogenic transmission electron microscopy was used to visualize the enzymatic activity of lipase-NP on well-defined lipid substrates. It was found that lipase-coated NPs are able to digest the substrates in a different manner in comparison to the free lipase.

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“…This arises from the fact that intensities of sharp peaks in diffraction pattern need to be detected rather than weak fringes arising from phase contrast in images. The transfer of phase contrast in HRTEM is very inefficient with respect to dose (Malac, Beleggia, Egerton, & Zhu, ) and with scintillator‐CCD detectors the signal may be comparable to noise. In comparison the corresponding diffraction peaks can be located easily because the strong diffraction peaks suffer less from readout noise of the CCD than HRTEM images (Malac et al, ).…”

Section: Resultsmentioning

confidence: 99%

Quality evaluation of ultra‐thin samples: Application to graphene

Cui

Bosnick

Indoe

et al. 2017

Microscopy Res & Technique

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Many new materials emerging are strictly two dimensional (2D), often only one or two monolayers thick. They include transition metal dichalcogenides, such as MoS , and graphene. Graphene in particular appears to have many potential applications. Typically the crystalline film without contamination is of interest. Therefore, a reliable method is needed to routinely evaluate the quality of the synthesized samples. Here, we present one such candidate method that utilizes standard electron diffraction and low/medium magnification imaging in a rudimentary transmission electron microscope. The electron irradiation dose is very low thus reducing electron irradiation damage of the investigated samples. As an example, the method was applied to the evaluation of as-grown graphene sample quality and a study on heating-induced change in graphene. It can be used to evaluate the volume and areal ratio of crystalline to noncrystalline component. The method is amiable to automated film quality evaluation.

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Bright-field TEM imaging of single molecules: Dream or near future?

Cited by 17 publications

References 32 publications

Inclusion of radiation damage dynamics in high-resolution transmission electron microscopy image simulations: The example of graphene

Inclusion of radiation damage dynamics in high-resolution transmission electron microscopy image simulations: The example of graphene

Enzymatic Activity of Lipase−Nanoparticle Conjugates and the Digestion of Lipid Liquid Crystalline Assemblies

Quality evaluation of ultra‐thin samples: Application to graphene

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