We developed this system further to minimize the background activity by combining the HRP DNAzyme with an F8 ribozyme.Wang2014 This way the stem that avoids the formation of the G-quadruplex can be designed stronger, as the F8 DNAzyme is able to cleave of a part of this stem. This results into a weakening of the stem that inhibits HRP-mimicking DNAzyme activity and thus to the formation of the G-quadruplex. The F8 DNAzyme was fused with aptamers so that in the presence of the ligand the F8 DNAzyme becomes active which then activates the HRP-mimicking DNAzyme (Fig. 6).
