Extended Data Fig. 4: Internal structures and operating mechanisms of the four dual-rail gates.
From: DNA-based programmable gate arrays for general-purpose DNA computing
a, Schematics showing internal structures of the dual-rail gates. AND gate has two series switches to respond to in1H and in2H respectively, generating outH in the presence of both in1H and in2H. Another switch responds to both L inputs, generating ouL in the presence of either in1L or in2L. OR gate has an opposite internal structure of AND gate. NOT gate has two switches, one for L input and one for H input. XOR contains four input-controlled switches. b–e, Signal transmission paths with all possible input combinations for AND (b), OR (c), NOT (d) and XOR (e) gates. High signals are shown in red and low signals in green. Single-stranded inputs bind to logic gates and release the corresponding output strands through SDRs. For AND gate, both in1L (representing in1 = 0) and in2L hybridize with s1 to displace s2 (=outL). in2H hybridizes with S3 to displace S5, exposing toehold γ for in1H to replace S4 (=outH).
