Basic Concepts of ELISA Kits

ELISA kits(Enzyme-Linked ImmunoSorbent Assay) have become a crucial tool in the field of biomedical research.

These kits are used for the detection and quantificationof specific substances in biological samples, such as proteins, peptides, and hormones. This is achieved through an antibodylinked to an enzyme, which will react after adding a substrate, resulting in a color change. This change is measured using spectrophotometry and reveals the presence of the sought substance, allowing for quantification.

Therefore, the main componentsof a kit include:

1. Microplate: Solid base containing wells to accommodate samples and reagents.


2. Antibodies:Proteins produced by an organism's immune system when it detects foreign substances, called antigens (which is what the kit aims to detect). Depending on the assay type, these antibodies (specific for detecting the substance of interest) are typically immobilized on the plate.


3. Enzyme:An enzyme is a protein that acts as a biological catalyst, accelerating the speed of a specific chemical reaction in the cell. In ELISA kits, it is bound to antibodies and produces a detectable signal when they bind to the target substance.


4. Chromogenic or Fluorogenic Substrate: Used as substrates for the enzymes linked to antibodies. They are colorless soluble molecules consisting of a chromophore (a chemical group that changes color after the enzymatic reaction).


5. Wash Solutions: Remove unbound reagents from the plate.

Understanding the main components of an ELISA kit helps comprehend the basic steps of the technique:

1. Coating:The biological sample containing the substance to be detected is added to the plate wells.


2. Blocking: A step that prevents non-specific binding of other substances to the well walls.


3. Incubation with the Sample: The solution of antibodies conjugated with the enzyme is added and incubated with the biological sample. These antibodies will bind to the substance to be detected.


4. Washing:Unbound substances are removed.


5. Incubation with the Enzyme Conjugate:The chromogenic substrate is added to react with the enzymes, marking the substance of interest.


6. Washing:Unwanted residues are eliminated.


7. Chromogenic or Fluorogenic Reaction:The detectable signal is produced.


8. Results Reading: The color or fluorescence intensity is measured and related to the concentration of the substance in the sample.

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These kits have various applications in fields such as:

• Medicine:Used to diagnose whether a patient has an infection or autoimmune disease. For example, some tests conducted using this technique include TAU protein (Alzheimer's diagnosis) or analysis of IgM and IgG antibodies against the SAR-CoV-2 virus.


• Veterinary:ELISA technique is widely used for the detection and diagnosis of diseases affecting livestock, birds, or pets.


• Food Industry:ELISA kits are commonly used for the detection of allergens (gluten, egg, soy, nuts, etc.) in food.

As seen, ELISA Kits are versatile tools with a wide range of applications. We take this opportunity to remind you that in our catalog, you can find over 8000 ELISA kits in our new ELK Biotechnologyline, ready for use with high specificity and precision.