What is Tris-EDTA Buffer?
Tris-EDTA (TE) buffer is a commonly used buffer solution in
histology, biochemistry, and molecular biology. It is composed of Tris (tris(hydroxymethyl)aminomethane) and EDTA (ethylenediaminetetraacetic acid). This buffer maintains a stable pH and chelates divalent cations, which are essential for various enzymatic reactions and DNA stabilization.
Components and Their Functions
Tris acts primarily as a buffering agent, maintaining the pH of the solution. It is effective over a pH range of 7 to 9, which is ideal for many biological reactions.
EDTA, on the other hand, is a chelating agent that binds to divalent metal ions such as Mg2+ and Ca2+. This prevents these ions from participating in enzymatic reactions that could degrade nucleic acids or proteins.
Preparation of Tris-EDTA Buffer
The preparation of TE buffer involves dissolving Tris and EDTA in distilled water and adjusting the pH with HCl or NaOH. Commonly, a 1X TE buffer contains 10 mM Tris and 1 mM EDTA, at a pH of 8.0. The stock solutions can be prepared at higher concentrations, such as 10X or 100X, and diluted as needed.Applications in Histology
In
histological studies, TE buffer is used for a variety of purposes:
DNA Extraction: The chelating property of EDTA protects DNA from degradation by inhibiting DNases, while Tris maintains a stable pH during the extraction process.
RNA Extraction: Similar to DNA extraction, TE buffer helps protect RNA from degradation by RNases.
Immunohistochemistry: TE buffer is used in antigen retrieval procedures to unmask epitopes, enhancing the binding of antibodies to their target proteins.
Electrophoresis: TE buffer is also used in gel electrophoresis to maintain the integrity of nucleic acids during separation.
Advantages and Disadvantages
TE buffer offers several advantages in histology: Stability: It provides a stable pH environment, crucial for various biochemical reactions.
Protection: EDTA protects nucleic acids from enzymatic degradation.
Versatility: It can be used in various applications including DNA and RNA extraction, electrophoresis, and immunohistochemistry.
However, there are some limitations:
pH Sensitivity: The effectiveness of Tris as a buffer is pH-dependent, which might require careful adjustment.
Interference: EDTA can interfere with certain downstream applications that require divalent cations.
Storage and Stability
TE buffer is generally stable at room temperature, but for long-term storage, it is advisable to keep it at 4°C. It can be autoclaved to ensure sterility, but the pH should be checked and adjusted if necessary after autoclaving.Conclusion
Tris-EDTA buffer is a versatile and essential reagent in the field of histology. Its ability to maintain a stable pH and protect nucleic acids from degradation makes it invaluable for a variety of laboratory procedures. Understanding its components, preparation, and applications can significantly enhance the efficiency and reliability of histological studies.
