Dark-Field X-Ray Microscopy of Immunogold-Labeled Cells

1996 ◽  
Vol 2 (2) ◽  
pp. 53-62 ◽  
Author(s):  
Henry N. Chapman ◽  
Jenny Fu ◽  
Chris Jacobsen ◽  
Shawn Williams
Keyword(s):  
Colloidal Gold ◽  
Dark Field Image ◽  
Dark Field ◽  
X Rays ◽  
X Ray ◽  
Scanning Transmission ◽  
A Cell ◽  
Specific Antigens ◽  
Genetic Sequences ◽  
Novel Method

The methods of immunolabeling make visible the presence of specific antigens, proteins, genetic sequences, or functions of a cell. In this paper we present examples of imaging immunolabels in a scanning transmission x-ray microscope using the novel method of dark-field contrast. Colloidal gold, or silver-enhanced colloidal gold, is used as a label, which strongly scatters x-rays. This leads to a high-contrast dark-field image of the label and reduced radiation dose to the specimen. The x-ray images are compared with electron micrographs of the same labeled, unsectioned, whole cell. It is verified that the dark-field x-ray signal is primarily due to the label and the bright-field x-ray signal, showing absorption due to carbon, is largely unaffected by the label. The label can be well visualized even when it is embedded in or laying behind dense material, such as the cell nucleus. The resolution of the images is measured to be 60 nm, without the need for computer processing. This figure includes the x-ray microscope resolution and the accuracy of the label positioning. The technique should be particularly useful for the study of relatively thick (up to 10 μm), wet, or frozen hydrated specimens.

Imaging of 30nm gold spheres by dark-field scanning transmission x-ray microscopy

1994 ◽  
Vol 52 ◽  
pp. 52-53
Author(s):  
Henry N. Chapman ◽  
Shawn Williams ◽  
Chris Jacobsen
Keyword(s):  
Dark Field ◽  
Important Application ◽  
X Rays ◽  
National Synchrotron Light Source ◽  
Bright Field ◽  
X Ray ◽  
Biological Objects ◽  
Scanning Transmission ◽  
Gold Labelling ◽  
Synchrotron Light

In a scanning transmission x-ray microscope (STXM), such as that operated at the beamline X-lA at the National Synchrotron Light Source, it is possible to obtain dark-field images by blocking the undeviated transmitted photons so that only x rays scattered by the specimen are detected. Although the signal that is detected in dark-field is much weaker than the conventional bright-field signal the method offers much higher contrast of small features and the possibility of detecting small features with higher signal to noise for the same incident x-ray flux. Also, the signal depends on both the amplitude and phase of the specimen, rather than just the amplitude. One important application of dark-field x-ray microscopy is the imaging of gold-labelled biological specimens. This unites the advantages of x-ray microscopy (the ability of imaging thick biological objects, low radiation dose) with those of gold labelling (specific-site or specific-protien labelling, well documented protocols).The x-ray microscope consists of the scanning transmission x-ray microscope, in which a zone-plate is used to focus monochromatic x rays to a probe, through which the sample is scanned.

Studies of metaphase chromosomes in the scanning transmission x-ray microscope: Image fidelity, radiation damage and specimen preparation

1992 ◽  
Vol 50 (2) ◽  
pp. 1038-1039
Author(s):  
Shawn Williams ◽  
Xiaodong Zhang ◽  
Susan Lamm ◽  
Jack Van’t Hof
Keyword(s):  
Visible Light ◽  
Radiation Damage ◽  
Cross Section ◽  
Imaging Techniques ◽  
Dose Range ◽  
Specimen Preparation ◽  
X Rays ◽  
Metaphase Chromosomes ◽  
X Ray ◽  
Scanning Transmission

The Scanning Transmission X-ray Microscope (STXM) is well suited for investigating metaphase chromosome structure. The absorption cross-section of soft x-rays having energies between the carbon and oxygen K edges (284 - 531 eV) is 6 - 9.5 times greater for organic specimens than for water, which permits one to examine unstained, wet biological specimens with resolution superior to that attainable using visible light. The attenuation length of the x-rays is suitable for imaging micron thick specimens without sectioning. This large difference in cross-section yields good specimen contrast, so that fewer soft x-rays than electrons are required to image wet biological specimens at a given resolution. But most imaging techniques delivering better resolution than visible light produce radiation damage. Soft x-rays are known to be very effective in damaging biological specimens. The STXM is constructed to minimize specimen dose, but it is important to measure the actual damage induced as a function of dose in order to determine the dose range within which radiation damage does not compromise image quality.

scholarly journals FEI Tecnai G2 F20

2016 ◽  
Vol 2 ◽  
Author(s):  
Martina Luysberg ◽  
Marc Heggen ◽  
Karsten Tillmann
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Dark Field ◽  
Conventional Imaging ◽  
Electron Loss ◽  
High Angle ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Set Up ◽  
Elemental Maps

The FEI Titan Tecnai G2 F20 is a versatile transmission electron microscope which is equipped with a Gatan Tridiem 863P post column image filter (GIF) and a high angle energy dispersive X-ray (EDX) detector. This set up allows for a variety of experiments such as conventional imaging and diffraction, recording of bright- and dark-field scanning transmission electron microscopy (STEM) images, or acquiring elemental maps extracted from energy electron loss spectra (EELS) or EDX signals.

scholarly journals Synthesis of nickel/gallium nanoalloys using a dual-source approach in 1-alkyl-3-methylimidazole ionic liquids

2019 ◽  
Vol 10 ◽  
pp. 1754-1767
Author(s):  
Ilka Simon ◽  
Julius Hornung ◽  
Juri Barthel ◽  
Jörg Thomas ◽  
Maik Finze ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Dark Field ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Dual Source ◽  
Induced Decomposition

NiGa is a catalyst for the semihydrogenation of alkynes. Here we show the influence of different dispersion times before microwave-induced decomposition of the precursors on the phase purity, as well as the influence of the time of microwave-induced decomposition on the crystallinity of the NiGa nanoparticles. Microwave-induced co-decomposition of all-hydrocarbon precursors [Ni(COD)2] (COD = 1,5-cyclooctadiene) and GaCp* (Cp* = pentamethylcyclopentadienyl) in the ionic liquid [BMIm][NTf2] selectively yields small intermetallic Ni/Ga nanocrystals of 5 ± 1 nm as derived from transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and supported by energy-dispersive X-ray spectrometry (EDX), selected-area energy diffraction (SAED) and X-ray photoelectron spectroscopy (XPS). NiGa@[BMIm][NTf2] catalyze the semihydrogenation of 4-octyne to 4-octene with 100% selectivity towards (E)-4-octene over five runs, but with poor conversion values. IL-free, precipitated NiGa nanoparticles achieve conversion values of over 90% and selectivity of 100% towards alkene over three runs.

A scanning transmission X-ray microscope at the Pohang Light Source

2018 ◽  
Vol 25 (3) ◽  
pp. 878-884 ◽  
Author(s):  
Hyun-Joon Shin ◽  
Namdong Kim ◽  
Hee-Seob Kim ◽  
Wol-Woo Lee ◽  
Chae-Soon Lee ◽  
...  
Keyword(s):  
Energy Range ◽  
Light Source ◽  
Photon Energy ◽  
Chemical State ◽  
Photon Energy Range ◽  
X Rays ◽  
X Ray ◽  
Space Resolution ◽  
Scanning Transmission ◽  
Pohang Light Source

A scanning transmission X-ray microscope is operational at the 10A beamline at the Pohang Light Source. The 10A beamline provides soft X-rays in the photon energy range 100–2000 eV using an elliptically polarized undulator. The practically usable photon energy range of the scanning transmission X-ray microscopy (STXM) setup is from ∼150 to ∼1600 eV. With a zone plate of 25 nm outermost zone width, the diffraction-limited space resolution, ∼30 nm, is achieved in the photon energy range up to ∼850 eV. In transmission mode for thin samples, STXM provides the element, chemical state and magnetic moment specific distributions, based on absorption spectroscopy. A soft X-ray fluorescence measurement setup has been implemented in order to provide the elemental distribution of thicker samples as well as chemical state information with a space resolution of ∼50 nm. A ptychography setup has been implemented in order to improve the space resolution down to 10 nm. Hardware setups and application activities of the STXM are presented.

scholarly journals CAE-COVIDX: automatic covid-19 disease detection based on x-ray images using enhanced deep convolutional and autoencoder

2021 ◽  
Vol 7 (1) ◽  
pp. 49
Author(s):  
Hanafi Hanafi ◽  
Andri Pranolo ◽  
Yingchi Mao
Keyword(s):  
Confusion Matrix ◽  
Virus Detection ◽  
Image Features ◽  
World Health ◽  
X Rays ◽  
X Ray ◽  
First Case ◽  
Long Time ◽  
Novel Method ◽  
Health Organization

Since the first case in 2019, Corona Virus has been spreading all over the world. World Health Organization (WHO) announced that COVID-19 had become an international pandemic. There is an essential section to handle the spreading of the virus by immediate virus detection for patients. Traditional medical detection requires a long time, a specific laboratory, and a high cost. A method for detecting Covid-19 faster compared to common approaches, such as RT-PCR detection, is needed. The method demonstrated that it could produce an X-ray image with higher accuracy and consumed less time. We propose a novel method to extract image features and to classify COVID-19 using deep CNN combined with Autoencoder (AE) dubbed CAE-COVIDX. We evaluated and compared it with the traditional CNN and existing framework VGG16 involving 400 normal images of non-COVID19 and 400 positive COVID-19 diseases. The performance evaluation was conducted using accuracy, confusion matrix, and loss evaluation. Based on experiment results, the CAE-COVIDX framework outperforms previous methods in several testing scenarios. This framework's ability to detect Covid-19 in various nonstandard image X-rays could effectively help medical employers diagnose Covid-19 patients. It is an important factor to decrease the spreading of Covid-19 massively.

scholarly journals Hard X-ray omnidirectional differential phase and dark-field imaging

2021 ◽  
Vol 118 (9) ◽  
pp. e2022319118
Author(s):  
Hongchang Wang ◽  
Kawal Sawhney
Keyword(s):  
Imaging Techniques ◽  
Dark Field ◽  
X Rays ◽  
Contrast Imaging ◽  
X Ray ◽  
Differential Phase ◽  
Dark Field Imaging ◽  
Spiral Path ◽  
Wide Range ◽  
Phase Images

Ever since the discovery of X-rays, tremendous efforts have been made to develop new imaging techniques for unlocking the hidden secrets of our world and enriching our understanding of it. X-ray differential phase contrast imaging, which measures the gradient of a sample’s phase shift, can reveal more detail in a weakly absorbing sample than conventional absorption contrast. However, normally only the gradient’s component in two mutually orthogonal directions is measurable. In this article, omnidirectional differential phase images, which record the gradient of phase shifts in all directions of the imaging plane, are efficiently generated by scanning an easily obtainable, randomly structured modulator along a spiral path. The retrieved amplitude and main orientation images for differential phase yield more information than the existing imaging methods. Importantly, the omnidirectional dark-field images can be simultaneously extracted to study strongly ordered scattering structures. The proposed method can open up new possibilities for studying a wide range of complicated samples composed of both heavy, strongly scattering atoms and light, weakly scattering atoms.

Imaging, Spectroscopy and Tomography of Frozen Hydrated Specimens With the Cryo Scanning Transmission X-Ray Microscope at The NSLS

1998 ◽  
Vol 4 (S2) ◽  
pp. 354-355
Author(s):  
J. Maser ◽  
C. Jacobsen ◽  
Y. Wang ◽  
A. Osanna ◽  
B. Winn ◽  
...  
Keyword(s):  
National Laboratory ◽  
Imaging Spectroscopy ◽  
Optical Resolution ◽  
Brookhaven National Laboratory ◽  
X Rays ◽  
X Ray ◽  
Measuring Techniques ◽  
Steady Improvement ◽  
Scanning Transmission ◽  
Synchrotron Light

With the steady improvement of x-ray optics with high resolution and efficiency, and continued development or adaptation of different imaging and measuring techniques, soft x-ray microscopy has emerged as a powerful method to image and analyze fully hydrated specimens of several micrometer thickness at sub-optical resolution (for a recent overview, see ref. 1). We report on experiments performed with the cryo scanning transmission x-ray microscope (cryo-STXM), which has recently come into operation at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory.Cryo-STXM uses x-rays with energies between the absorption edge of Carbon (E = 284 eV) and Oxygen (E = 543 eV) from the soft x-ray undulator at the NSLS. Fully hydrated specimens such as eucaryotic cells in water or ice layers of up to 10 micrometer thickness can be imaged without any additional need for contrast enhancing techniques.

scholarly journals Combining Nanofocused X-Rays with Electrical Measurements at the NanoMAX Beamline

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 432 ◽  
Author(s):  
Lert Chayanun ◽  
Susanna Hammarberg ◽  
Hanna Dierks ◽  
Gaute Otnes ◽  
Alexander Björling ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Current Measurement ◽  
Fourth Generation ◽  
X Rays ◽  
Induced Current ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
X Ray ◽  
Scanning Transmission ◽  
Insight Into

The advent of nanofocused X-ray beams has allowed the study of single nanocrystals and complete nanoscale devices in a nondestructive manner, using techniques such as scanning transmission X-ray microscopy (STXM), X-ray fluorescence (XRF) and X-ray diffraction (XRD). Further insight into semiconductor devices can be achieved by combining these techniques with simultaneous electrical measurements. Here, we present a system for electrical biasing and current measurement of single nanostructure devices, which has been developed for the NanoMAX beamline at the fourth-generation synchrotron, MAX IV, Sweden. The system was tested on single InP nanowire devices. The mechanical stability was sufficient to collect scanning XRD and XRF maps with a 50 nm diameter focus. The dark noise of the current measurement system was about 3 fA, which allowed fly scan measurements of X-ray beam induced current (XBIC) in single nanowire devices.

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