Tissue Fixation
Tissue Fixation - Related Videos
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.
08:46
Fixation of Embryonic Mouse Tissue for Cytoneme Analysis
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Cited by 5 •
2022
Here, an optimized step-by-step protocol is provided for fixation, immunostaining, and sectioning of embryos to detect specialized signaling filopodia called cytonemes in developing mouse tissues.
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.
02:41
Cryopreserved Tissue Section Fixation and Staining: A Procedure to Process Frozen Brain Tissue Sections for Laser Microdissection
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2023
This video presents the fixation and staining method to process frozen mouse brain tumor tissue. The processed tissue helps differentiate and obtain a specific population of cells during subsequent laser capture microdissection.
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...
FAQs
Formaldehyde-based fixation and alcohol-based fixation preserve tissue through different chemical effects. Formaldehyde creates cross-links between cellular components, helping maintain relationships within the specimen. Alcohol-based agents instead remove water and precipitate proteins. This distinction matters because the resulting preservation can influence how clearly morphology appears and how accessible specific target molecules remain during later analysis.
Exposure time and fixative conditions directly affect the balance between structural preservation and molecular accessibility. Insufficient treatment may leave tissue vulnerable to autolysis or decomposition, whereas excessive or prolonged fixation can obscure cellular details or reduce access to target molecules. Researchers therefore treat fixative choice and exposure as variables that must match the intended downstream study.
Chemical stabilization can preserve the tissue relationships needed to visualize morphology, but the same treatment may limit access to target molecules. This trade-off is important in immunohistochemistry, which analyzes specific molecular targets within tissue. A specimen may therefore retain an overall useful appearance while producing weaker or less accessible target-related staining after excessive or prolonged fixation.
Once fixation is complete, the specimen can enter a linked preparation sequence: tissue processing, embedding, sectioning, and staining. These steps convert a preserved sample into thin, stainable sections suitable for observation. The resulting preparation can then be examined by light microscopy or, when appropriate, electron microscopy, allowing structural features to be evaluated in an organized workflow.
Fixative selection should follow the kind of preservation and analysis required. Formaldehyde is relevant when chemical cross-linking is used to stabilize cellular components, whereas alcohol-based agents provide preservation through water removal and protein precipitation. Because each approach affects morphology and target-molecule access differently, the planned histology, microscopy, or immunohistochemistry application should guide the choice.
In biology, tissue fixation provides a common preparation step for examining organization at the tissue and cellular levels. It supports histology, which evaluates tissue morphology, and immunohistochemistry, which examines target molecules in tissue. It also prepares specimens for light or electron microscopy. Its value lies in preserving material long enough for these complementary analyses to be performed.