Implementation of half adder and half subtractor with a simple and universal DNA-based platform

As a powerful material, DNA presents great advantages in the fabrication of molecular devices and higher-order logic circuits. Herein, by making use of the hybridization and displacement of DNA strands, as well as the formation and dissociation of a G-quadruplex, a simple and universal DNA-based platform is developed to implement half-adder and half-subtractor arithmetic processes. The novel feature of the designed system is that the two required logic gates for the half adder (an AND and an XOR logic gate integrated in parallel) or the half subtractor (an XOR and an INHIBIT logic gate integrated in parallel) are achieved simultaneously with the same platform and are triggered by the same set of inputs. Another novel feature is that the developed half adder and half subtractor are operated by the same DNA platform in an enzyme-free system and share a constant threshold setpoint. These investigations provide a new route towards prototypical DNA-based arithmetic operations and promote the development of advanced logic circuits. A simple and universal DNA-based platform is developed to implement the required two logic gates of a half adder (or a half subtractor) in parallel triggered by the same set of inputs. The developed half adder and half subtractor are operated with the same DNA platform in an enzyme-free system. The investigations provide a new way for the prototypical DNA-based arithmetic operations and also the development of advanced circuits. The recognition and hybridization abilities of DNA make it very suitable for the construction of logic gates that process data (in the form of one or more inputs) into a specific output. By exploiting the hybridization and replacement of DNA strands, as well as the formation and dissociation of the G-quadruplex motif, Yaqing Liu and Erkang Wang from the Chinese Academy of Sciences in Changchun, China, and colleagues have devised a general DNA platform that carries out ‘half-adder’ and ‘half-subtractor’ operations. These combinational circuits respectively add and subtract digits in complex operations that necessitate two logic gates operating in parallel. In previous designs, these gates were typically implemented on different platforms or triggered by different inputs. However, these issues are overcome in the present system as the two component gates now respond to the same set of inputs based on the same platform.