Figure 36.

Different approaches for detection of proteins using nucleic acid aptamers. (A) Redox-labeled aptamer alters its conformation after aptamer–protein complex formation, positioning the label closer to the electrode.⁸⁸⁵ (B) Strategy employing two aptamers, electrode-immobilized aptamer for capturing the protein and a second aptamer labeled with enzyme for EC monitoring of enzymatic reaction.⁸⁸⁶ (C) Approach similar to that in (B), with the second aptamer being labeled with gold nanoparticle–ferrocene conjugate.⁸⁸⁷