<P> Performing an ELISA involves at least one antibody with specificity for a particular antigen . The sample with an unknown amount of antigen is immobilized on a solid support ( usually a polystyrene microtiter plate ) either non-specifically ( via adsorption to the surface ) or specifically ( via capture by another antibody specific to the same antigen , in a `` sandwich '' ELISA ) . After the antigen is immobilized , the detection antibody is added , forming a complex with the antigen . The detection antibody can be covalently linked to an enzyme , or can itself be detected by a secondary antibody that is linked to an enzyme through bioconjugation . Between each step , the plate is typically washed with a mild detergent solution to remove any proteins or antibodies that are non-specifically bound . After the final wash step , the plate is developed by adding an enzymatic substrate to produce a visible signal , which indicates the quantity of antigen in the sample . </P>
<P> Performing an ELISA involves at least one antibody with specificity for a particular antigen . The sample with an unknown amount of antigen is immobilized on a solid support ( usually a polystyrene microtiter plate ) either non-specifically ( via adsorption to the surface ) or specifically ( via capture by another antibody specific to the same antigen , in a `` sandwich '' ELISA ) . After the antigen is immobilized , the detection antibody is added , forming a complex with the antigen . The detection antibody can be covalently linked to an enzyme , or can itself be detected by a secondary antibody that is linked to an enzyme through bioconjugation . Between each step , the plate is typically washed with a mild detergent solution to remove any proteins or antibodies that are non-specifically bound . After the final wash step , the plate is developed by adding an enzymatic substrate to produce a visible signal , which indicates the quantity of antigen in the sample . </P>
what component of the elisa causes the amplified signal
what component of the elisa causes the amplified signal
an enzymatic substrate
an enzymatic substrate