Osmium Tetroxide Post-fixation
Osmium Tetroxide Post-fixation - Related Videos
02:44
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
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2025
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry. Syn Dihydroxylation Mechanism The reaction comprises a two-step mechanism. It begins with the addition of osmium tetroxide across the alkene double bond in a concerted manner forming a...
10:21
Protocol for HER2 FISH Using a Non-cross-linking, Formalin-free Tissue Fixative to Combine Advantages of Cryo-preservation and Formalin Fixation
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Cited by 3 •
2017
Fluorescence in-situ hybridization (FISH) is often required in combination with histopathology and molecular diagnostics for selection of therapy in personalized medicine. A novel non-cross-linking, formalin-free tissue fixative that allows high quality morphologic, molecular and FISH analyses from the same specimen by addition of a post-fixation step before FISH is presented.
08:53
Whole Animal Perfusion Fixation for Rodents
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Cited by 531 •
2012
Here we describe a low-cost, rapid, controlled and uniform fixation procedure using 4% paraformaldehyde perfused via the vascular system: through the heart of the rat to obtain the best possible preservation of the brain.
01:03
Fixation and Sectioning
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2023
Two basic types of preparation are used to visualize specimens with a light microscope: wet mounts and fixed specimens. The simplest type of preparation is the wet mount, in which the specimen is placed in a drop of liquid on the slide. A liquid specimen can be directly deposited on the slide using a dropper. Solid specimens, such as skin scraping, can be placed on the slide before adding a drop of liquid to prepare the wet mount. Sometimes the liquid is simply water, but stains are often added...
07:51
Acrylic Resin Molding Based Head Fixation Technique in Rodents
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Cited by 4 •
2016
Traditional head fixation techniques have used metallic frames attached on the skull as an interface for head fixation apparatus. This protocol demonstrates a frameless, acrylic resin molding based head fixation technique for behavioral tasks in rodents.
FAQs
Osmium tetroxide targets unsaturated lipids, so its reaction stabilizes membrane components and contributes electron density. In transmission electron microscopy, this added density makes membrane boundaries and lipid-rich structures easier to distinguish in ultrathin sections. The improved visibility supports examination of organelle architecture and membrane organization at ultrastructural resolution within fixed cells.
The post-fixation step complements rather than replaces aldehyde fixation. Aldehyde fixation provides the initial preservation before osmium tetroxide is applied; the second treatment then reacts with unsaturated lipids, stabilizes membrane structures, and increases electron density. Maintaining this sequence prepares the specimen for subsequent dehydration, resin embedding, and ultrathin sectioning.
Membrane junctions, organelles, and lipid-rich structures particularly benefit from the increased electron density produced during treatment. This contrast helps distinguish boundaries and internal features that are important for interpreting cellular ultrastructure. In cancer specimens, the resulting sections can support close examination of mitochondrial architecture, membrane alterations, and contacts between neighboring cells.
After the secondary fixation, specimens proceed through dehydration, resin embedding, and ultrathin sectioning before examination by transmission electron microscopy. Osmium treatment contributes membrane stabilization and contrast before these preparation stages. The workflow therefore links chemical preservation of lipid-containing structures with production of thin sections suitable for visualizing cellular ultrastructure.
Cancer researchers use this preparation approach to examine tumor-cell morphology and ultrastructural changes in mitochondria, membranes, and cell-cell contacts. It also supports visualization of interactions between tumor cells and the surrounding microenvironment. These observations provide structural evidence that can be considered alongside malignant behavior, treatment response, and disease progression.
Detailed structural observations can help researchers relate altered organelles, membranes, and cellular contacts to broader cancer phenotypes. Comparing these features across tumor conditions or treatment contexts may clarify how structural changes accompany malignant behavior, response to therapy, or disease progression. The method therefore contributes microscopic evidence for interpreting cancer biology at the cellular level.