Enzyme-linked Immunosorbent Assay
Enzyme-linked Immunosorbent Assay - Related Videos
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Enzyme-Linked Immunosorbent Assay
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2023
In 1971, Peter Perlman and Eva Engvall developed an Enzyme-linked immunosorbent assay (ELISA or EIA). ELISA differs from western blot in that the assays are conducted in microtiter plates or in vivo rather than on an absorbent membrane. There are many different types of ELISAs, but they all involve an antibody molecule whose constant region binds an enzyme, leaving the variable region free to bind its specific antigen. Enzyme-substrate reaction allows the antigen to be visualized or quantified.
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Assessing Lentiviral Titer Using an Enzyme-Linked Immunosorbent Assay
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2026
Source: Vijayraghavan, S., et al. Protocol for the Production of Integrase-deficient Lentiviral Vectors for CRISPR/Cas9-mediated Gene Knockout in Dividing Cells. J. Vis. Exp. (2017).This video demonstrates the use of a p24 ELISA to estimate viral titers of lentiviral vectors. The assay involves lysing viral particles to release p24, capturing it with specific antibodies, and detecting it with a peroxidase-linked system that produces a measurable color change. By comparing sample absorbance...
03:20
Quantifying Bacterial Alginate Using an Antibody-Based Enzyme-Linked Immunosorbent Assay
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2025
Source: Al Ahmar, R., et al. Culture of Small Colony Variant of Pseudomonas aeruginosa and Quantitation of its Alginate. J. Vis. Exp. (2020)This video demonstrates a colorimetric immunoassay to quantify alginate, a protective exopolysaccharide produced by Pseudomonas aeruginosa. The procedure involves coating a microplate with the sample, applying specific antibodies, and using an enzyme-substrate reaction to generate a measurable color change. A standard curve is then used to determine the...
02:57
Enzyme-Linked Immunosorbent Assay to Verify Chemically-Coupled Antibody-Antigen Conjugates
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2025
This video demonstrates the detection of chemically conjugated antibody-antigen complexes via the sandwich enzyme-linked immunosorbent assay, or ELISA, technique. The captured antibody binds to the specific epitope of the antigen of the antibody-antigen conjugate, which can be later visualized using an enzyme-linked secondary antibody.
05:57
Sex Hormone Detection In Human Tear Film Using Enzyme-Linked Immunosorbent Assays
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2026
This protocol describes an optimized enzyme-linked immunosorbent assay (ELISA) method to detect and quantify 17β-estradiol and testosterone in human tear fluid collected via microcapillary tubes. This approach enables minimally invasive measurement of tear hormone levels.
FAQs
Selective binding helps distinguish the intended antigen or antibody from other substances in a biological sample. This molecular recognition contributes to assay specificity, while the enzyme-generated color signal allows the bound target to be measured. Together, these features support clinically useful interpretation when ELISA is applied to disease markers, immune responses, hormones, or other biomarkers.
The immobilized target or capture antibody provides a fixed location where the relevant molecule can be retained on a solid surface. A detection antibody then recognizes the bound target and carries the linked enzyme that produces the measurable signal. Using these components in sequence connects selective molecular binding with quantitative color development.
The enzyme converts a suitable substrate into a colored product, transforming an antibody–antigen interaction into an observable measurement. The resulting color change is related to the amount of target present, so the detection step supports measurement rather than simple recognition alone. This relationship is central to evaluating biomarker levels in biological samples.
A basic workflow begins by immobilizing the target or capture antibody on a solid surface, followed by introducing the biological sample so selective binding can occur. A detection antibody linked to an enzyme is then used, and a suitable substrate is added to generate color. The measured color provides information about the target amount.
ELISA is useful when a study or clinical test needs to detect or measure a defined antigen, antibody, hormone, or other biomarker in a biological sample. Its sensitivity, specificity, and scalable format support clinical screening, disease monitoring, and biomedical investigation. It can also help assess immune responses associated with infectious diseases or other conditions.
Depending on the target selected for the assay, ELISA can provide evidence about infectious disease markers, immune responses, hormone levels, or other biomarkers. Because the color signal relates to the amount of target present, results can support measurement as well as detection. This makes the method relevant to both diagnostic assessment and biomedical research.