This website uses cookies to ensure you get the best experience on our website.
- Table of Contents
Boster Bio Life Science Blog
Explore key IHC principles such as antigen retrieval, counterstains, and fluorophore selection. Our expert tips enhance tissue staining clarity and protocol efficiency.
-
In IHC experiments, many researchers take for granted the familiar blue stain on every slide – hematoxylin – and may overlook its role. As one expert put it, “How many of us take the time to think about which counterstain would be the best choice?”. Counterstaining can have a big impact on your IHC results. Most cells are colorless and transparent, so without a background stain, even a perfectly developed antibody signal can be hard to place. A good counterstain provides contrast and context, helping antibody-stained cells “stand out more” and pinpointing their exact location in the tissue.Read more
-
In immunohistochemistry (IHC), using fluorescently labeled antibodies is a common method to detect protein expression and localization. The choice of fluorophores directly affects image quality, signal-to-noise ratio, and experimental reproducibility. Researchers must consider experimental equipment, target abundance, and other conditions to select suitable dyes.Read more
-
In conducting immunohistochemistry (IHC) and immunofluorescence (IF) experiments, one crucial step is the fixation of cells to preserve them. This prevents cell autolysis and degradation caused by proteolytic enzymes and increases the mechanical strength of the cell structure. Fixation ensures the cell's morphology and structure remain intact, maintaining a "lifelike" appearance.Read more
-
Cancer metastasis is a leading cause of poor prognosis in cancer patients and represents a central challenge in oncology research. The process of metastasis is highly complex and involves multiple steps: local invasion, entry into the circulatory system, dissemination through blood or lymphatic vessels, seeding in distant tissues, and subsequent growth in a new environment.Read more
-
Read more
What Is IHC Staining?
Immunohistochemistry (IHC) is a vital technique in biomedical research and clinical diagnostics, enabling the visualization and localization of specific proteins within tissue samples. In this blog, we outline the different types of IHC staining, including direct and indirect...
-
Read more
What Is Sodium Citrate Buffer Used For?
Sodium citrate buffer, also known as citrate buffer, is a common reagent used for antigen retrieval in immunohistochemistry. Immunohistochemistry (IHC) is a technique that enables high-quality visualization of proteins in a variety of tissues. IHC is a multi-step process that comprises fixation, embedding, and sectioning of a target tissue followed by incubation with an antibody targeting a protein of interest.
How It Helps in Protein Detection
Once the tissue is fixed, embedded in paraffin, and sectioned on slides, researchers can utilize antibodies to target and identify their protein of interest. However, fixation and embedding of tissues, often with 10% formalin and paraffin respectively, initiates cross-linking of proteins that can mask antigen epitopes. Antigen masking may reduce the sensitivity of antibodies and decrease the detection of certain proteins of interest. A process known as antigen retrieval breaks the bonds between formalin and proteins, removing the effects of cross-linking, thereby enabling better detection of proteins. Sodium citrate buffer is highly used in the process of antigen retrieval, specifically for heat-induced antigen retrieval. Boster Bio offers a simple-to-use Sodium Citrate Buffer (Catalog# AR0024) for heat-induced antigen retrieval to remove the effects of antigen masking in your IHC experiments.
Antigen Retrieval in IHC
What is Antigen Retrieval?
Antigen retrieval is a process of breaking the bonds from cross-linking, enabling proteins to interact with antibodies during immunohistochemistry. The purpose of antigen retrieval in immunohistochemistry is to unmask antigens in fixed tissues, which can significantly improve the quality of staining and detection of proteins. While optimization of this method may add additional steps to an already multi-step, complex procedure, antigen retrieval has improved IHC...
-
Read more
Overview of Antigen Retrieval Techniques
Antigen retrieval is essential in immunohistochemistry (IHC) due to protein cross-linking caused by formalin fixation, which masks antigenic sites and hinders antibody binding. Formaldehyde fixation usually generates methylene bridges which cross-link proteins and therefore mask the epitope of interest. It is essential to unmask the antibody...
-
Read more
Proper fixation workflows support reliable antibody performance when experiments depend on monoclonal antibodies or Polyclonal antibodies.
Importance of Fixation in IHC/ICC
Why Proper Fixation is Essential
Sample fixation is a required and crucial step for every successful IHC/ICC experiment. Appropriate fixation of samples provides the following benefits during the tissue preparation process. Without proper fixation, cellular structures can collapse, antigens may degrade, and staining results become unreliable. Reliable fixation helps achieve specific staining while minimizing background staining that can interfere with interpretation. Within standardized immunohistochemistry services, fixation parameters are carefully controlled to support consistent staining performance across diverse sample types. Controlled protocols also help preserve protein-protein interaction, enabling more accurate biological analysis.
How Fixatives Preserve Morphology and Antigenicity
Fixatives work by stabilizing proteins and other cellular components, either by creating cross-links or by precipitating molecules to maintain structural integrity. This chemical stabilization preserves the spatial arrangement of cells and tissues, allowing accurate localization of antigens and reliable analysis.
Maintaining structural integrity is especially important for studies evaluating protein-protein interaction within complex tissue environments.
Choosing which fixing solution to use depends on your sample type and antigen. Since there is no standard fixing solution for all samples, we recommend testing to determine which specific type of solution will be most appropriate and effective for antigen immobilization in your sample. Optimization often includes adjusting Incubation time to balance antigen preservation with antibody accessibility. This step is particularly important when preparing slides for a multiplex IHC service, where inconsistent fixation can compromise the detection of multiple targets within the same section. Improper fixation may increase background staining and reduce specific staining clarity. For samples undergoing diagnostic evaluation or complex biomarker analysis, an expert Pathology Review Service ensures tissue quality and fixation adequacy before interpretation, improving experimental accuracy. Expert review can help confirm compatibility with monoclonal antibodies and Polyclonal antibodies.
As an example, compare the morphologies demonstrated below using different fixatives, both photographed at the same magnification.
Differences in morphology often reflect variations in incubation time and fixation chemistry.
On the left: A paraffin section of the small intestine mucosa that has been fixed in neutral buffered formalin, a cross-linking fixative. Nuclear and cytoplasmic preservation is satisfactory but some cellular shrinkage is present.
Cross-linking fixatives typically support strong specific staining with reduced background staining when protocols are optimized.
On the right: A paraffin section of the small intestine mucosa that has been fixed in 95% ethanol, a denaturing fixative. While nuclear preservation is fair, there is substantial shrinkage of cytoplasmic and extracellular elements.
Denaturing fixatives may alter protein-protein interaction if fixation conditions are not carefully controlled.
Several fixing solutions are available for use and should be chosen based on the sample type or antigen studied in the experiment. Below are the 3 different categories of fixatives:
Selection should consider antibody type, Incubation time, and the need to limit background staining.
Aldehyde Fixatives
How Aldehyde Fixatives Work
Aldehyde fixatives are di-functional cross-linking agents, which are widely used due to their strong penetrability, low contractibility, and low background. They help keep the cross-linking between tissues and maintain the antigen.
These properties make aldehydes compatible with both monoclonal antibodies and Polyclonal antibodies.
Common Examples of Aldehyde Fixatives
- Formaldehyde
- Formalin (Neutral Buffered Formalin)
- Paraformaldehyde
- Glutaraldehyde
- Bouin’s Solution
- Zamboni’s Solution
Proper Incubation time with aldehyde fixatives is necessary to prevent excessive background staining.
Formaldehyde vs. Formalin vs. Paraformaldehyde
Formaldehyde and formalin are often referred to interchangeably. They are similar, but their chemical compositions are in fact different. Formalin (aka NBF) is a saturated water solution consisting of 37 to 40% (w/v) formaldehyde, which is diluted with a phosphate buffer to...
-
Read more
Why Are IHC Controls Important?
Immunohistochemistry (IHC) is a popular protein detection method that utilizes antibody-antigen interactions to visualize the distribution and localization of specific cellular components within cells and in their proper tissue context. This methodology also forms the basis for more complex techniques like Multiplex...
Popular Posts
Recent Posts
