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An Enzyme-linked immunosorbent assay (ELISA) is a fast, robust and sensitive high throughput method for the detection of a target molecule in a liquid sample.
Most common target molecules:
- proteins
- peptides
- antibodies
- small biomolecules such as hormones or second messengers

Depending on the setup, the target molecule can also be quantified within the sample. Usually, ELISAs are done in 96 well or 384 well microtiter plates. The signal is generated by an enzymatic reaction, catalyzing either a colorimetric or fluorometric reaction. Related techniques use different, non-enzymatic readouts, e.g. electrochemiluminescence (ECL) or radioactivity (radioimmunoassay, RIA).

Multiple different ELISA setups exist; the Indirect ELISA and the Sandwich ELISA are among the most common ones.

Indirect ELISA

The analyte (target molecule) is immobilized on a microtiter plate. An unlabeled primary antibody is then bound to the analyte. The analyte is indirectly detected by an enzyme-labeled secondary antibody, which recognizes the primary antibody.


Sandwich ELISA

A capture antibody recognizing the analyte (target molecule) is coated onto the microtiter plate. The analyte is then bound to the capture antibody and then detected by a second, enzyme-labelled antibody, which provides the signal for the assay readout. Since the analyte is bound simultaneously by the capture antibody and the labelled antibody, this setup is called “Sandwich ELISA”.


Looking for references? Please check our literature database.

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