Transmission Electron Microscopy of the Retina: A Method for Sample Preparation and Evaluation

2020 ◽  
pp. 019262332095412
Author(s):  
Christopher M. Hayden ◽  
Emily K. Meseck
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Clinical Examination ◽  
Spherical Shape ◽  
Disease Models ◽  
Posterior Aspect ◽  
Orientation Imaging ◽  
Transmission Electron

Ultrastructural pathology is critical in the morphologic evaluation and characterization of subcellular structures in nonclinical toxicity and efficacy studies. In murine models of ophthalmologic disease, clinical examination is typically paired with other techniques like electroretinography (ERG) and/or optical coherence tomography (OCT) to more fully characterize a finding. High-quality transmission electron microscopy (TEM) can provide a critical, image-based link between these approaches, providing greater confidence in interpretation of ERG or OCT results. In addition to characterization of disease models, TEM can provide detailed visualization of retinal changes identified by clinical examination or light microscopy in nonclinical toxicity studies. The spherical shape of the eye presents unique challenges for trimming, orientation, imaging, and evaluation by TEM. The varied components of the eye require specialized approaches for embedding to facilitate successful sectioning. Controlling for the orientation of the retina is critical to consistent evaluation, driving the need for an improved method of embedding this unique and complex organ. The authors describe a method of sample preparation resulting in optimal orientation of the posterior aspect of murine eyes (rat and mouse) for TEM of the neural retina, Bruch’s membrane and/or choroid, with examples from mouse ophthalmic disease models.

scholarly journals Synthesize and Characterization of Hollow Boron-Nitride Nanocages

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
W. S. Zhang ◽  
J. G. Zheng ◽  
W. F. Li ◽  
D. Y. Geng ◽  
Z. D. Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Boron Nitride ◽  
Growth Mechanism ◽  
Spherical Shape ◽  
Amorphous Boron ◽  
Transmission Electron ◽  
Ammonia Atmosphere

The boron-nitride (BN) nanocages are synthesized by nitrogenation of amorphous boron nanoparticles at 1073 K under nitrogen and ammonia atmosphere. The BN nanocages exhibit a well-crystallized feature with nearly pentagonal or spherical shape, depending on their size. High-resolution transmission electron microscopy studies reveal that they are hollow nanocages. The growth mechanism of the BN nanocages is proposed.

Orientation Imaging in Scanning Electron and Transmission Electron Microscopy for Characterization of the Shear Banding Phenomenon

2006 ◽  
Vol 155 (1-2) ◽  
pp. 243-250 ◽  
Author(s):  
Henryk Paul ◽  
Adam Morawiec ◽  
Emmanuel Bouzy ◽  
Jean-Jacques Fundenberger ◽  
Andrzej Piątkowski
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Shear Banding ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
Scanning Electron

Visualisation of Electrically Active Areas Using Electron Holography

2002 ◽  
Author(s):  
U. Muehle ◽  
A. Lenk ◽  
M. Lehmann ◽  
H. Lichte
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Electron Holography ◽  
Transmission Electron ◽  
Structural Details ◽  
Different Types ◽  
High Level ◽  
Technical Solutions

Abstract In accordance with the predictions of the International Semiconductor Association, a further decrease in the structural widths of semiconductor devices is expected. For an in-depth characterization of actual structural details, the transmission electron microscopy (TEM)-technique is becoming more and more significant. An urgent requirement is in the visualization of dimensions of the doped regions and estimation of p-n-junctions profile with a high level spatial resolution. The off-axis electron holography, a special TEM-technique, is able to visualize electrically active areas in semiconductors. This article describes a way to achieve sample preparation for TEM-holography from actual memory products and also provides an idea of the potential of this technique for semiconductor failure analysis. It shows that different types and sizes of FET's and testing structures could be visualized by focusing on the physical basics, technical solutions, and sample preparation.

Improving transmission electron microscopy characterization of semiconductors by minimizing sample preparation artifacts

1992 ◽  
Vol 70 (10-11) ◽  
pp. 875-880 ◽  
Author(s):  
J. P. McCaffrey ◽  
G. I. Sproule ◽  
R. Sargent
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Ion Milling ◽  
Transmission Electron ◽  
Transmission Electron Microscopy Characterization ◽  
Silicon Based ◽  
Microscopy Characterization ◽  
Preparation Techniques

Techniques employed for the preparation of transmission electron microscopy (TEM) samples can introduce artifacts that obscure subtle detail in the materials being studied. Traditional semiconductor sample preparation techniques rely heavily on ion milling, which leaves amorphous layers on ion milled surfaces and some intermixing across interfaces, thus degrading the TEM images of these samples. Experimental results of the extent of this amorphization and intermixing are presented for silicon-based semiconductor samples, and methods to minimize these effects are suggested. These methods include variations in ion milling parameters that reduce the extent of the artifacts, and improvements in the small-angle cleavage technique that eliminate these artifacts completely.

scholarly journals TEM Sample Preparation: An Interdisciplinary Website

2009 ◽  
Vol 17 (2) ◽  
pp. 38-41 ◽  
Author(s):  
Jeanne Ayache ◽  
Luc Beaunier ◽  
Jacqueline Boumendil ◽  
Gabrielle Ehret ◽  
Danièle Laub
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Material Science ◽  
International Community ◽  
Central Importance ◽  
Transmission Electron ◽  
Characterization Of Materials ◽  
Preparation Techniques

Sample preparation is of central importance for the characterization of materials by transmission electron microscopy (TEM). As a guide to researchers seeking practical help on the use of all types of TEM sample preparation techniques, we have created an Internet website. This website has been designed in French and is now translated into English. The website is accessible free of charge.The TEMSAMPREP website, figure 1 http://temsamprep.in2p3.fr/, is the result of a synergistic effort of an atypical team of five electron microscopy scientists having different research specialties in physics, mineralogy, material science, and biology. They shared five years of human adventure in creating the website to transmit their 30 years of TEM experience to the international community.

scholarly journals Towards Cellular Ultrastructural Characterization in Organ-on-a-Chip by Transmission Electron Microscopy

Applied Nano ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 289-302
Author(s):  
Adrianna Glinkowska Mares ◽  
Natalia Feiner-Gracia ◽  
Yolanda Muela ◽  
Gema Martínez ◽  
Lidia Delgado ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endothelial Cells ◽  
Sample Preparation ◽  
Preparation Method ◽  
Sample Preparation Method ◽  
Transmission Electron ◽  
Ultrastructural Characterization ◽  
Organ On A Chip

Organ-on-a-chip technology is a 3D cell culture breakthrough of the last decade. This rapidly developing field of bioengineering intertwined with microfluidics provides new insights into disease development and preclinical drug screening. So far, optical and fluorescence microscopy are the most widely used methods to monitor and extract information from these models. Meanwhile transmission electron microscopy (TEM), despite its wide use for the characterization of nanomaterials and biological samples, remains unexplored in this area. In our work we propose a TEM sample preparation method, that allows to process a microfluidic chip without its prior deconstruction, into TEM-compatible specimens. We demonstrated preparation of tumor blood vessel-on-a-chip model and consecutive steps to preserve the endothelial cells lining microfluidic channel, for the chip’s further transformation into ultrathin sections. This approach allowed us to obtain cross-sections of the microchannel with cells cultured inside, and to observe cell adaptation to the channel geometry, as well as the characteristic for endothelial cells tight junctions. The proposed sample preparation method facilitates the electron microscopy ultrastructural characterization of biological samples cultured in organ-on-a-chip device.

Tumor Diagnosis

1982 ◽  
Vol 40 ◽  
pp. 262-265
Author(s):  
Bruce Mackay
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Diagnosis ◽  
Light Microscopy ◽  
Clinical Examination ◽  
Ultrastructural Study ◽  
Diagnostic Procedures ◽  
Specific Diagnosis ◽  
Transmission Electron ◽  
Microscopic Diagnosis

The broadest application of transmission electron microscopy (EM) in diagnostic medicine is the identification of tumors that cannot be classified by routine light microscopy. EM is useful in the evaluation of approximately 10% of human neoplasms, but the extent of its contribution varies considerably. It may provide a specific diagnosis that can not be reached by other means, but in contrast, the information obtained from ultrastructural study of some 10% of tumors does not significantly add to that available from light microscopy. Most cases fall somewhere between these two extremes: EM may correct a light microscopic diagnosis, or serve to narrow a differential diagnosis by excluding some of the possibilities considered by light microscopy. It is particularly important to correlate the EM findings with data from light microscopy, clinical examination, and other diagnostic procedures.

Characterization of submicrometer fluid Inclusions in minerals by Analytical/Transmission Electron Microscopy and electron diffraction

1990 ◽  
Vol 48 (4) ◽  
pp. 424-424
Author(s):  
George Guthrie ◽  
David Veblen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Light Microscopy ◽  
Fluid Inclusions ◽  
Energy Dispersive Spectrometer ◽  
Analytical Transmission Electron Microscopy ◽  
Transmission Electron

The nature of a geologic fluid can often be inferred from fluid-filled cavities (generally <100 μm in size) that are trapped during the growth of a mineral. A variety of techniques enables the fluids and daughter crystals (any solid precipitated from the trapped fluid) to be identified from cavities greater than a few micrometers. Many minerals, however, contain fluid inclusions smaller than a micrometer. Though inclusions this small are difficult or impossible to study by conventional techniques, they are ideally suited for study by analytical/ transmission electron microscopy (A/TEM) and electron diffraction. We have used this technique to study fluid inclusions and daughter crystals in diamond and feldspar.Inclusion-rich samples of diamond and feldspar were ion-thinned to electron transparency and examined with a Philips 420T electron microscope (120 keV) equipped with an EDAX beryllium-windowed energy dispersive spectrometer. Thin edges of the sample were perforated in areas that appeared in light microscopy to be populated densely with inclusions. In a few cases, the perforations were bound polygonal sides to which crystals (structurally and compositionally different from the host mineral) were attached (Figure 1).

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