Figure 1.

Schematic displays of the (a) electrochemical biosensing strategies developed for miR-21 determination based on the use of an iridium(III) complex which selectively and stably interacted with G-quadruplex DNA acting as a peroxidase-like mimic; (b) catalyzed hairpin assembly target coupled with recycling and enzyme signal amplification. Reprinted from [21] (a) and [20] (b) with permission.