Design And Application Of Molecular Recognition Circuit Based On DNA Strand Displacement

Since 1946,when the first computer with highspeed computing power was created,the search for a new type of computing was necessary as modern technology has gradually reached the limits of Moore’s law and the search for a new type of computing was necessary for the progress of the times.The precise Watson-Crick base complementary pairing principle has made DNA possible as a new type of computer material.The controllability of DNA strand replacement technology and its excellent computational power have led to a wide range of applications in the field of DNA computing.In order to enrich the information processing of DNA computing,this paper proposes a molecular recognition circuit based on DNA strand substitution technology,and on this basis,we design and implement a molecular comparator circuit for constructing reversible numerical comparators of one and many bits.The main research elements are as follows:First,a DNA molecular recognition circuit was constructed based on a seesaw gate circuit,which consists of three modules: molecular recognition,cumulative summation,and fluorescence reporting of results.Through Visual DSD simulation and biochemical experimental analysis,the logical feasibility and stability of the recognition circuit were verified.The biggest advantage of the circuit is that the fluorescence reporting process does not require molecular annihilation reaction,but direct fluorescence reporting.Compared to traditional molecular circuits,the design reduces DNA strands,leakage,and complexity.Molecular recognition circuit with computational potential for arbitrary inputs.Second,the design implements a molecular comparator based on a DNA molecule recognition circuit combined with a cross suppressor,a modular functional circuit that provides a basis for the study of DNA computation.The logical feasibility of the design was demonstrated by Visual DSD simulations and further verified by fluorescence reporter experiments.The design allows for a comparison function of signals through a simple cascade reaction.Finally,based on the implementation of molecular comparators,reversible numerical comparators of one and many bits are constructed,which provide a design idea for quantitative analysis tasks in biosensors.Compared with the irreversible operation of traditional computers,this paper proposes a reversible operation by designing a reversible molecular gate circuit to make the input signal fully responsive and reduce the loss of information during the operation.The logic design of this paper is simulated by Visual DSD and the simulation experiments are conducted for one-,two-and four-bit reversible numerical comparators,and the results are in accordance with the pre-designed results,further verifying the logical rigor of the design.In summary,this paper has developed a DNA molecular recognition circuit by DNA strand replacement technique;designed a molecular comparators based on the molecular recognition circuit combined with a cross suppressor;constructed one-and multi-bit reversible numerical comparators;and finally demonstrated the accuracy and feasibility of the theoretically designed molecular comparator by fluorescence report experimental presentation,and also verified the accuracy of the reversible numerical comparator by Visual DSD simulation experiments.The accuracy of the reversible numerical comparator is also verified by Visual DSD simulation experiments.The molecular recognition circuit developed in this paper has the computational potential for arbitrary inputs and provides the basis for future large-scale multi-input DNA molecular circuits.The modular functional molecular comparator circuit can be cascaded to implement other functions after reaction,providing a basis for research on DNA computing.