Figure 1.

Domain representation of the catalytic DNA strand displacement system from Zhang et al.²⁴ and four example leakage pathways. (a) In the catalyzed strand displacement pathway of the reaction network, a catalyst strand initiates a reaction cycle driven forward thermodynamically by a net gain in entropy. The strand displacement exchanges the catalyst for the signal strand and exposes a sequestered toehold on the substrate backbone for the fuel, which reacts with the intermediate to complete the cycle and form a waste duplex. Sequences and domains are listed in Supporting Information S1. (b) In the four leakage pathways, the fuel reacts with the substrate backbone in the absence of a catalyst by exploiting fraying at the 5′, nick, and 3′ locations of the substrate.