**6. Aptamers with chemiluminescence immunoassay**

Li et al. [33] developed an aptamer structure switch experiment with horseradish peroxidase (HRP) labeling for sensitive absorbance and chemiluminescence detection of small molecules. Differently from competitive enzyme-linked immunosorbent assay (ELISA), they fixed the cDNA of the aptamer to the surface of the microporous plate.
