Molecular Logic Operation Based On DNA Strand Displacement

DNA strand displacement technology is a dynamic DNA nanotechnology developed on the basis of DNA self-assembly technology.DNA strand displacement technology can realize the dynamic connection between input signal and output signal,which is a new method to construct logic gate and logic circuit.Based on the DNA strand displacement reaction,this paper mainly studies molecular logic circuit model of specific functions,which are Half subtractor,One-digit full subtractor,Two-digit full subtractor,and two improved molecular logic circuit model.Finally,the models are simulated and verified by Visual DSD(DNA Strand Displacement)simulation platform.The main research contents are as follows.Firstly,in order to construct the molecular logic circuit,first of all digital logic gates are translated into the corresponding dual-rail logic gates and molecular logic gates,and the basic molecular "AND" gate and "OR" gate are constructed based on DNA strand displacement response and dual-rail thought.Then the Half subtractor molecular logic circuit model is constructed based on strand displacement theory.Half subtractor is simulated in DSD.The correctness of the simulation results proves the rationality of the design of circuit,which lays a theoretical foundation for the next construction of complex logic circuit.Secondly,in order to realize the the complex operation function of DNA computer,One-digit full subtractor and Two-digit full subtractor are constructed on the basis of Half subtractor.According to the dual-rail thought and the construction of seesaw gates,the corresponding biochemical logic circuits are constructed.Then,the simulation experiments of the models are carried out by the Visual DSD simulation platform.The simulation results correctly express the logic "0" and the logic "1" state,which shows the feasibility of the model design.The design method is provided for the construction of multi-digit full subtractor,which lays a foundation for the construction of DNA computer.Thirdly,in order to realize multi-function and reduce the complexity of the operation,the circuits are improved and two improved operation models are constructed,namely,One-bit half adder-half subtractor and One-bit full adder-full subtractor molecular logic circuit model.Based on the dual-rail thought and the construction of seesaw gates,the molecular computation models of One-bit half adder-half subtractor and One-bit full adder-full subtractor are constructed,which reduce the complexity of computation in some ways.Finally,the rationality of the design is verified by DSD,which provides thought of the next expansion of multifunctional circuits and paves the way for the research of biological computer.