Single-stranded DNA Toehold Switch Controlled Versatile Biocircuit Construction

Synthetic biological circuit is an important research field of synthetic biology in recent years,which uses biomolecules to construct biological systems with logical control function.Synthetic biological circuit is to develop biomolecules into different functional components by engineering,and reassemble these modularized elements into artificial control system.The purpose of the development of biological circuits is to make it possible for people to regulate the biological function of cells in an engineering way.At present,the programmability,flexibility and modular design of synthetic biological circuit make it an important biotechnology.This ariticle studies the engineering construction method of multifunctional biological circuit based on single-stranded DNA toehold switch regulation.Among them,the computer-aided design of single-stranded DNA "toehold" switch can achieve high specificity and recognition of the target nucleic acid molecules through the strand displacement reaction mechanism.Based on this,we use the DNA switch as a core control element,and implement a simple single-way or even cyclic biological circuit system.The cascade circuit driven by a single-strand DNA switch is constructed and its performance is analyzed.In addition,we have attempted to use the DNA switch for gene expression regulation in cell-free protein expression systems,successfully demonstrating that the long single-stranded DNA molecules(982 bp)can also achieve complete gene expression in vitro artificial biological systems.This research has developed a standardized,modular biological circuit construction technology with a single-stranded DNA "toehold" switch as the core control component,which can provide a firm technical foundation for the construction of complex artificial biological circuits in the future,and is applied to disease diagnosis,gene networks,and in the field of research such as artificial life.