Fig. 9. (a) Programmed triggered DNAzyme-stimulated transformations within pH-/K⁺-ion-responsive origami dimer nanostructures: treatment of the origami dimer tile D₂, state I, at pH = 9.5, in the presence of the “helper” strands, H₁, H₂, leads to the unlocking of the T-A·T locks and to the formation of the nanocavity-containing dimer, state II. The assembly of the E_3a/E_3b subunits into the Mg²⁺-ion-dependent DNAzyme in the confined nanocavity leads to the hydrolytic cleavage of substrate S₃ and to the switched “ON” fluorescence of FAM (λ = 518 nm). Subjecting the dimer D₂, state I, to K⁺ ions and H₁/H₂ results in the dictated unlocking of the K⁺-ion-responsive tile and to the formation of the nanocavity-containing tile in state III. Under these conditions the E_2a/E_2b tethers are assembled in the nanocavity with the catalytically active Mg²⁺-ion-dependent DNAzyme fluorescence of Cy5 (λ = 665 nm). Treatment of the dimer origami D₂, state I, with K⁺ ions at pH = 9.5, in the presence of the “helper” strands H₁/H₂ leads to the formation of the nanocavities in the two origami rafts and to the activation of the two Mg²⁺-ion-dependent DNAzymes in the nanocavities, respectively, state IV. This leads to the concomitant cleavage of the two substrates S₃ and S₂ and to the switched-ON fluorescence at λ = 518 nm and λ = 665 nm. (b) Fluorescence intensities of the fluorophores FAM and Cy5 generated by the respective DNAzymes in the origami dimer structures in states I, II, III and IV.