ELISA is an immunological test that involves the interaction of high specificity between antigens and antibodies. ELISA can be used to detect target molecules at low concentrations with a high degree of precision by combining this interaction with a colorimetric, fluorescent, or chemiluminescent signal that is mediated by an enzyme. Over time, it developed; the technique has been of various formats, and each has been developed to address various analytical needs.
Principle of ELISA
The basic concept of ELISA is to immobilize either an antigen or an antibody on a solid surface, which in most cases is a microtiter plate. An enzyme with a corresponding antibody or antigen is then added. When a proper substrate is added, the enzyme reacts, giving a measurable signal proportional to the quantity of target analyte in the sample.
Types of ELISA
ELISA may be conducted in various forms, such as direct, indirect, sandwich, and competitive ELISA. Direct ELISA effect is using antibodies that are enzyme-labeled to bind directly to the antigen, whereas indirect ELISA incorporates the use of a secondary antibody to amplify the signal. Sandwich ELISA has high specificity by binding the antigen between two antibodies, and competitive ELISA is utilized with small molecules or when a single antibody is present.
Applications of ELISA
ELISA is widely applied to medical diagnostics to detect hormones, cytokines, pathogens, and disease biomarkers. It is also used in food testing to detect allergens and contaminants, in environmental research to track pollutants, and in pharmaceutical research to develop drugs and to control quality.
