Quantifying Amyloid-beta 42 via Sandwich ELISA

Sandwich-enzyme-linked immunosorbent assay (sandwich-ELISA) was used to detect the content of Aβ42 (Elabscience). Aβ42 in the sample or standard substance was bound to Aβ42 antibody coated on the solid phase carrier of an enzyme-labeled plate. Biotin anti-Aβ42 antibody was then bound to the Aβ42 antibody, and labeled biotin was specifically bound to horseradish peroxidase (HRP)-labeled avidin to form an immune complex. The colour-developing substrate tetramethylbenzidine (TMB) was then catalysed to form a blue complex, which turned yellow after the reaction was terminated with a termination liquid. The intensity of the colour of the complex was proportional to the amount of Aβ42 in the sample.