A pH-regulated stimuli-responsive strategy for RNA-cleaving DNAzyme

RNA-cleaving DNAzymes possess important roles in DNAzymes and have been widely used in the biosensors, DNA nanomachines owing to their ion-specific dependence. However, there are still challenges in constructing universal but versatile stimuli-responsive strategies of RNA-cleaving DNAzymes. Herein, a stimuli-responsive strategy for RNA-cleaving DNAzyme is proposed by the artful design of hairpin nanostructure, in which the activities of DNAzyme (Pb 2+ -dependent DNAzyme as a model) in the hairpin’s loop are pH-regulated by using the triplex stem as the “lock”. Upon introducing the “key”, pH values, the DNAzyme will be activated and fragment the substrate of it in the presence of Pb 2+ , accompanied by the turn-on of the fluorescence quenched by fluorescence resonance energy transfer (FRET). The regulation ability of pH can be controlled by the length and sequence of the triplex stem, and the wide pH regulation range may be helpful for the application of DNAzymes in biological medicine delivery systems.