Entropy-driven deoxyribozyme circuit. (A) Scheme for the amplification module, based on an entropy-driven, strand-exchange amplifier. The functional domains within each DNA strand have been color-coded (see Table 1 for the sequence of each domain). Complementary domains are represented by light and dark variation of the same color (i.e., light green pairs with dark green). An asterisk in the names of sub-domains indicates complementarity (i.e., sub-domain 1t* is complementary to sub-domain 1t). Gray dashed arrows indicate where toehold binding should initiate. Arrows and dots on DNA strands represent 3' termini and 5' termini, respectively. (B) Scheme for the reporter module based on an allosteric G-quadruplex peroxidase. The domain containing the G-quadruplex is colored in purple.