Imaging of SARS-CoV-2 infected Vero E6 cells by helium ion microscopy

• Natalie Frese,
• Patrick Schmerer,
• Martin Wortmann,
• Matthias Schürmann,
• Matthias König,
• Michael Westphal,
• Friedemann Weber,
• Holger Sudhoff and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2021, 12, 172–179, doi:10.3762/bjnano.12.13

• 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. Keywords: bioimaging; cell membrane; charge compensation; helium ion microscopy; SARS-CoV-2; Vero E6 cells; Introduction The last decade of helium ion microscopy (HIM) was characterized by a rapid exploration

• resolution of the HIM, compared to the SEM [23]. A further benefit of HIM is its charge compensation capability during secondary electron detection. SEM imaging of biological specimen usually necessitates a thin conductive coating to prevent negative charge accumulation from the impinging electrons. Such

Bio-imaging with the helium-ion microscope: A review

• Matthias Schmidt,
• James M. Byrne and
• Ilari J. Maasilta

Beilstein J. Nanotechnol. 2021, 12, 1–23, doi:10.3762/bjnano.12.1

• . This is possible owing to the combination of a large depth of focus and the possibility of charge compensation [6], by pointing an electron beam emitted from a flood gun, onto the area of analysis. The first HIM micrographs of biological specimens were published between 2007 and 2010 [2][5][7], but did

• blackening of the charged areas in the micrograph. Charge compensation One of the most frequently cited advantages of using HIM compared to SEM for bio-imaging is the possibility to image typically non-conductive biological specimens without the prior coating with a thin layer of metal to make their surfaces

• surface in order to avoid charging. Charge compensation can even be considered to be necessary for conductive metals, because the high surface sensitivity of the HIM would only reveal the metal layer and not the fine detail of the surface ultrastructure without the use of the flood gun. From a practical

Free and partially encapsulated manganese ferrite nanoparticles in multiwall carbon nanotubes

• Saja Al-Khabouri,
• Salim Al-Harthi,
• Toru Maekawa,
• Mohamed E. Elzain,
• Ashraf Al-Hinai,
• Ahmed D. Al-Rawas,
• Abbsher M. Gismelseed,
• Ali A. Yousif and
• Myo Tay Zar Myint

Beilstein J. Nanotechnol. 2020, 11, 1891–1904, doi:10.3762/bjnano.11.170

• values was estimated to be equal to ±0.1 eV. Due to the charging effect of the oxides, electron flooding was carried out for charge compensation. A helium lamp with 21.2 eV (He I) excitation energy was used for ultraviolet photoemission spectroscopy (UPS, Omicron Nanotechnology). A −5 V sample bias was

Out-of-plane surface patterning by subsurface processing of polymer substrates with focused ion beams

• Serguei Chiriaev,
• Luciana Tavares,
• Vadzim Adashkevich,
• Arkadiusz J. Goszczak and
• Horst-Günter Rubahn

Beilstein J. Nanotechnol. 2020, 11, 1693–1703, doi:10.3762/bjnano.11.151

• deposited onto the surface of the polymer substrates to study the patterning of these films by in-bulk processes. An important argument for using metal films is that these films prevent surface charging. The use of charge compensation by irradiation with electron beams can generate additional radiation

Tuning the performance of vanadium redox flow batteries by modifying the structural defects of the carbon felt electrode

• Ditty Dixon,
• Deepu Joseph Babu,
• Aiswarya Bhaskar,
• Hans-Michael Bruns,
• Joerg J. Schneider,
• Frieder Scheiba and
• Helmut Ehrenberg

Beilstein J. Nanotechnol. 2019, 10, 1698–1706, doi:10.3762/bjnano.10.165

• samples were analyzed using a focused (30–400 µm spot size), monochromatic Al Kα X-ray source. The Kα charge compensation system was employed during the experiment, using electrons of 8 eV energy and low-energy argon ions to prevent any localized charge build-up. The spectra were fitted with one or more

Stationary beam full-field transmission helium ion microscopy using sub-50 keV He⁺: Projected images and intensity patterns

• Michael Mousley,
• Santhana Eswara,
• Olivier De Castro,
• Olivier Bouton,
• Nico Klingner,
• Christoph T. Koch,
• Gregor Hlawacek and
• Tom Wirtz

Beilstein J. Nanotechnol. 2019, 10, 1648–1657, doi:10.3762/bjnano.10.160

• higher brightness GFIS source. To further understand the cause of the deflection pattern, a triangular BN particle was placed in a commercial HIM and SE images were recorded for comparison. The HIM SE images, taken with and without charge compensation by electron flooding are shown Figure 4A and Figure

• collection of deflected trajectories. The dashed red line (s) shows the sample plane and the dot-dashed black line (m) shows the MCP plane. A) HIM SE image with charge compensation by electron flooding and B) HIM SE image without charge compensation. C) THIM deflection from the BN particle showing three

Growth of lithium hydride thin films from solutions: Towards solution atomic layer deposition of lithiated films

• Ivan Kundrata,
• Karol Fröhlich,
• Lubomír Vančo,
• Matej Mičušík and
• Julien Bachmann

Beilstein J. Nanotechnol. 2019, 10, 1443–1451, doi:10.3762/bjnano.10.142

• collected using the pass energy of 50 eV. Charge compensation was achieved with the system dual beam flood gun. The Thermo Scientific Avantage software, version 5.9904 (Thermo Fisher Scientific), was used for digital acquisition and data processing. Spectral calibration was determined by using the automated

pH-mediated control over the mesostructure of ordered mesoporous materials templated by polyion complex micelles

• Emilie Molina,
• Mélody Mathonnat,
• Jason Richard,
• Patrick Lacroix-Desmazes,
• Martin In,
• Philippe Dieudonné,
• Thomas Cacciaguerra,
• Corine Gérardin and
• Nathalie Marcotte

Beilstein J. Nanotechnol. 2019, 10, 144–156, doi:10.3762/bjnano.10.14

• 7.9), the N/AA ratio sharply drops whereas EO/Si further decreases. The low value of N/AA is quite surprising since the charge density of OC decreases strongly above pH 6.5, and then even higher values of N/AA could be expected as a result of the necessary charge compensation in the PIC nanophase. Let

Zn/F-doped tin oxide nanoparticles synthesized by laser pyrolysis: structural and optical properties

• Florian Dumitrache,
• Iuliana P. Morjan,
• Elena Dutu,
• Ion Morjan,
• Claudiu Teodor Fleaca,
• Monica Scarisoreanu,
• Alina Ilie,
• Marius Dumitru,
• Cristian Mihailescu,
• Adriana Smarandache and
• Gabriel Prodan

Beilstein J. Nanotechnol. 2019, 10, 9–21, doi:10.3762/bjnano.10.2

• of the number of recombination centers and enhancement of “the electron–hole pair separation to stimulate the change in the bandgap by eliminating the impurity states” by charge compensation between positive and negative ion dopants, and it can also “facilitate the overall mixing of the impurity

Controlling surface morphology and sensitivity of granular and porous silver films for surface-enhanced Raman scattering, SERS

• Sherif Okeil and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2018, 9, 2813–2831, doi:10.3762/bjnano.9.263

• using a microfocused, monochromated Al Kα X-ray source (30–400 µm spot size). The K-Alpha charge compensation system was employed during analysis, using electrons of 8 eV energy and low-energy argon ions to prevent any localized charge build-up. Auger spectroscopy was performed using a PHI 680 (Physical

SO₂ gas adsorption on carbon nanomaterials: a comparative study

• Deepu J. Babu,
• Divya Puthusseri,
• Frank G. Kühl,
• Sherif Okeil,
• Michael Bruns,
• Manfred Hampe and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2018, 9, 1782–1792, doi:10.3762/bjnano.9.169

• , monochromated Al Kα X-ray source (30–400 µm spot size). The K-Alpha charge compensation system was employed during analysis, using electrons of 8 eV energy and low-energy argon ions to prevent any localized charge build-up. The spectra were fitted with one or more Voigt profiles (binding energy uncertainty

Single-step process to improve the mechanical properties of carbon nanotube yarn

• Maria Cecilia Evora,
• Xinyi Lu,
• Nitilaksha Hiremath,
• Nam-Goo Kang,
• Kunlun Hong,
• Roberto Uribe,
• Gajanan Bhat and
• Jimmy Mays

Beilstein J. Nanotechnol. 2018, 9, 545–554, doi:10.3762/bjnano.9.52

• analyzer with a 128-channel detector. Survey data were collected at 200 eV pass energy and an energy resolution of 1 eV/step, while core level data were collected at 50 eV pass energy and 0.1 eV/step energy resolution. Sample charging was eliminated by using the dual-beam charge compensation source of the

Bombyx mori silk/titania/gold hybrid materials for photocatalytic water splitting: combining renewable raw materials with clean fuels

• Stefanie Krüger,
• Michael Schwarze,
• Otto Baumann,
• Christina Günter,
• Michael Bruns,
• Christian Kübel,
• Dorothée Vinga Szabó,
• Rafael Meinusch,
• Verónica de Zea Bermudez and
• Andreas Taubert

Beilstein J. Nanotechnol. 2018, 9, 187–204, doi:10.3762/bjnano.9.21

• Scientific, East Grinstead, UK). Data acquisition and processing using the Thermo Avantage software is described elsewhere [53]. All samples were analyzed using a micro-focused, monochromated Al Kα X-ray source (30–400 µm spot size). The K-Alpha+ charge compensation system was employed during analysis, using

Dry adhesives from carbon nanofibers grown in an open ethanol flame

• Christian Lutz,
• Julia Syurik,
• C. N. Shyam Kumar,
• Christian Kübel,
• Michael Bruns and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2017, 8, 2719–2728, doi:10.3762/bjnano.8.271

• Grinstead, UK). Data acquisition and processing using the Thermo Avantage software is described elsewhere [32]. All samples were analyzed using a micro-focused, monochromated Al Kα X-ray source (30–400 μm spot size). The K-Alpha charge compensation system was employed during analysis, using electrons of 8

Nitrogen-doped twisted graphene grown on copper by atmospheric pressure CVD from a decane precursor

• Ivan V. Komissarov,
• Nikolai G. Kovalchuk,
• Vladimir A. Labunov,
• Ksenia V. Girel,
• Olga V. Korolik,
• Mikhail S. Tivanov,
• Algirdas Lazauskas,
• Mindaugas Andrulevičius,
• Tomas Tamulevičius,
• Viktoras Grigaliūnas,
• Šarunas Meškinis,
• Sigitas Tamulevičius and
• Serghej L. Prischepa

Beilstein J. Nanotechnol. 2017, 8, 145–158, doi:10.3762/bjnano.8.15

• oxygen-based functional groups, charge compensation effects and doping can significantly affect the C 1s response [37][38]. Therefore, analysis of the N 1s core level is necessary to verify the status of nitrogen. Figure 10a and Figure 10b present the high-resolution XPS data for the N 1s spectrum of

Hydration of magnesia cubes: a helium ion microscopy study

• Ruth Schwaiger,
• Johannes Schneider,
• Gilles R. Bourret and
• Oliver Diwald

Beilstein J. Nanotechnol. 2016, 7, 302–309, doi:10.3762/bjnano.7.28

• , most importantly, without coating the samples for charge compensation. Sample charging effects that typically occur during imaging of insulating samples can be counteracted in the HIM by using a low-energy electron flood gun for charge compensation [7]. Although charging is a problem for MgO, in this

3D solid supported inter-polyelectrolyte complexes obtained by the alternate deposition of poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate)

• Eduardo Guzmán,
• Armando Maestro,
• Sara Llamas,
• Jesús Álvarez-Rodríguez,
• Francisco Ortega,
• Ángel Maroto-Valiente and
• Ramón G. Rubio

Beilstein J. Nanotechnol. 2016, 7, 197–208, doi:10.3762/bjnano.7.18

• the polyelectrolyte multilayers. Keywords: charge compensation; hydration; polyelectrolyte multilayers; stratification; swelling; Introduction The new requirements of science and technology have created an increasing interest for the fabrication of materials with reduced dimensionality for their

• . This behavior is explained by the co-deposition of counterions with the polymer chains, which becomes more prominent as the ionic strength increases. This type of behavior is on the basis of a charge compensation mechanism that will be discussed below. The compensation mechanism is related to the

• consider two different aspects that influence the film assembly: the charge inversion (overcompensation) that occurs during the deposition of the successive layers, and the charge compensation that ensures the neutrality of the supramolecular architecture. The charge inversion or overcompensation has been

pH-Triggered release from surface-modified poly(lactic-co-glycolic acid) nanoparticles

• Manuel Häuser,
• Klaus Langer and
• Monika Schönhoff

Beilstein J. Nanotechnol. 2015, 6, 2504–2512, doi:10.3762/bjnano.6.260

• directly correlated to the pH of PAA during adsorption. In case of the titration curves obtained for PAA adsorbed at pH 5 and pH 7, respectively, a decrease of surface potential is observed after reaching its maximum value (see Figure 2). This can be attributed to surface charge compensation effects

• of polyelectrolyte multilayers [15][32][33][34][35] while others described the influence of pH on weak polyelectrolyte layer build-up [36][37]. General concepts of the relevance of the solution conformation have been derived [31]. Concerning charge diluted chains it can be argued that charge

• compensation, required to compensate the charge density of the terminating layer, determines the surface charge density of the subsequently adsorbing layer. Thus, an adsorbing charge-diluted chain requires a larger amount of mass, yielding thicker films [21][38]. At pH 3, PAA is weakly charged, and therefore

Self-organization of gold nanoparticles on silanated surfaces

• Htet H. Kyaw,
• Salim H. Al-Harthi,
• Azzouz Sellai and
• Joydeep Dutta

Beilstein J. Nanotechnol. 2015, 6, 2345–2353, doi:10.3762/bjnano.6.242

• measurements were conducted in ultrahigh high vacuum conditions of 2 × 10−10 mbar. In order to reduce surface charging effects, all the measured samples were flooded with electrons for charge compensation during the XPS measurements. The binding energies were calibrated with respect to adventitious C 1s

Electrospray deposition of organic molecules on bulk insulator surfaces

• Antoine Hinaut,
• Rémy Pawlak,
• Ernst Meyer and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2015, 6, 1927–1934, doi:10.3762/bjnano.6.195

• ) is short compared to the charge compensation time (days), a charged surface is obtained. In our setup, a positive bias is applied to the solution containing the diporphyrin molecules. Therefore, droplets produced during ESI as well as the molecules reaching the surface are positively charged. This

Imaging of carbon nanomembranes with helium ion microscopy

• André Beyer,
• Henning Vieker,
• Robin Klett,
• Hanno Meyer zu Theenhausen,
• Polina Angelova and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2015, 6, 1712–1720, doi:10.3762/bjnano.6.175

• can visualize them. However, CNMs are electrically insulating, which makes them sensitive to charging. We demonstrate that the helium ion microscope (HIM) is a good candidate for imaging freestanding CNMs due to its efficient charge compensation tool. Scanning with a beam of helium ions while

• report, we will show examples that support this statement. We demonstrate the effect of charging on HIM images as well as the effectiveness of the HIM charge compensation mechanism. The principle of operation of HIM as well as a recent overview of HIM-related reports can be found elsewhere [17]. In short

• well as charge compensation can reduce or completely avoid the charging of insulating membranes. These imaging parameter changes resulted in Figure 1d, which does not show any notable charging effects. Here, the sample was mounted in a way that no secondary electrons from the sample holder could reach

Scanning reflection ion microscopy in a helium ion microscope

• Yuri V. Petrov and
• Oleg F. Vyvenko

Beilstein J. Nanotechnol. 2015, 6, 1125–1137, doi:10.3762/bjnano.6.114

• detectable step height was found to be approximately 5 nm. RIM imaging of an insulator surface without the need for charge compensation was successfully demonstrated. Keywords: helium ion microscope; low-angle ion scattering; reflection microscopy; surface imaging; surface morphology; Introduction

• microscopy of cleaved mica Figure 6 shows an RI image of a cleaved mica surface obtained at a magnification of 100,000× under the grazing angle of 5° without charge compensation or conductive coatings. One can see that all details of the step-like surface are well reproduced without any noticeable image

• incidence from 0° to 10° results in the relative variation of the shadow width of a few percent and does not affect the accuracy of the measurements. In summary, reflection ion microscopy is useful for imaging of the surface of dielectric materials without the need for charge compensation, and the

Towards bottom-up nanopatterning of Prussian blue analogues

• Virgile Trannoy,
• Marco Faustini,
• David Grosso,
• Sandra Mazerat,
• François Brisset,
• Alexandre Dazzi and
• Anne Bleuzen

Beilstein J. Nanotechnol. 2014, 5, 1933–1943, doi:10.3762/bjnano.5.204

• were collected at a pass energy of 10 eV for S 2p core XPS levels. No charge compensation was applied during acquisition. Results and Discussion The gold layer The silicon wafer and the samples Au10, Au20 and Au50 were studied by AFM. Representative AFM images are shown in Figure 1. After gold

Near-field photochemical and radiation-induced chemical fabrication of nanopatterns of a self-assembled silane monolayer

• Ulrich C. Fischer,
• Carsten Hentschel,
• Florian Fontein,
• Linda Stegemann,
• Christiane Hoeppener,
• Harald Fuchs and
• Stefanie Hoeppener

Beilstein J. Nanotechnol. 2014, 5, 1441–1449, doi:10.3762/bjnano.5.156

• (Figure 4c). This indicates that in this case a double layer of the negatively charged gold nanoparticles might be adsorbed. Unlike in the case of the specific chemical binding of the fluorescein tags, more or less than a monolayer can be bound to the positively charged nanopattern due to charge

• compensation, depending on the surface charges of the nanopattern and of the nanoparticles which may alter their properties under different conditions of the sample preparation. For the 0.22 µm nanopattern, which cannot be identified in the fluorescence images, the topography images taken on the same

Towards precise defect control in layered oxide structures by using oxide molecular beam epitaxy

• Federico Baiutti,
• Georg Christiani and
• Gennady Logvenov

Beilstein J. Nanotechnol. 2014, 5, 596–602, doi:10.3762/bjnano.5.70

• , for instance, to solubility limits or to the tendency of atoms intermixing at interfaces resulting in cationic redistribution or intergrowth of secondary phases. Moreover, how do charge compensation mechanisms act at interfaces? What is the result of the “polar discontinuity” and of the presence of