Study On Fluorescence Sensing Analysis Method And Performance Based On DNA Strand Displacement Strategy

Chain substitution refers to the process of two partially or completely complementary chains hybridizing with each other,replacing one or more pre hybrid chains during this process.Chain permutation is a wandering branch migration process that begins at the toehold starting point in a complementary single chain domain.DNA nanotechnology is a promising strategy that utilizes Boolean logic behavior to develop and process biological information molecules.By utilizing the concept of toe point mediated chain substitution,DNA can be dynamically"programmed"in the field of nanomolecules,with high sequence specificity and adjustable complex dynamic processes.Fluorescence detection methods are widely used in the field of biological analysis and detection due to their commercial availability of broad-spectrum fluorescent groups,convenience of fluorescence labeling,real-time response,and inherent real-time detection capabilities.In this paper,the detection of target molecules and the control of dynamic DNA dissipative by using chain transposition strategy with the aid of efficient fluorescence detection methods.The specific research content is summarized as follows:1.Compared with signal amplification strategies without enzymes or with a single enzyme,the method of combining two biological enzymes,polymerase and cleaving enzyme,to detect target molecules has higher sensitivity and detection performance.However,due to the limitation that the catalytic ability of biological enzymes is affected by environmental temperature,higher requirements are put forward for the design of probe sequences.We have developed an allosteric DNA molecular machine driven by polymerase Klenow and cleaving enzyme Nb.Bbv CI,which utilizes a DNA signal amplification strategy for highly sensitive and specific detection of HPV type 16 pathogenic genes.Starting from the process of hybridization between the target chain T and a single stranded H2 with a cleaving enzyme Nb.Bbv CI recognition site to replace the stem ring type DNA H1 with a cleaving enzyme Nb.Bbv CI recognition site and a G quadruplex complementary chain,a large number of specific base sequence chains G containing the G-quadruplex are generated through the cyclic action of polymerase and cleaving enzyme.Then,under the action of K~+,the G-quadruplex is formed to catalyze the reduction of thiamine to fluorescent products.At the same time as the main line reaction continues to circulate,the two branch line auxiliary reactions also occur simultaneously,achieving the recycling of the target.The detection limit of 10 a M indicates that the design scheme is not only simple to operate and easy to capture fluorescence signals,but also capable of high sensitivity target detection and exponential signal amplification in the presence of trace targets.2.DNA nanotechnology utilizes DNA strands to manipulate the spatial and temporal distribution of substances,which can be roughly divided into structural and dynamic DNA nanotechnology.Structural DNA nanotechnology has utilized"bottom-up"DNA self-assembly to construct two-dimensional and three-dimensional objects of different sizes and complexities,reaching their peak in macroscopic materials with nanoscale addressability.In contrast,dynamic DNA nanotechnology is guided by reconfigurable design and autonomous driven devices,exploring equilibrium end states and more complex and interesting non equilibrium dynamics.In this context,a dynamic DNA strategy based on DNA strand substitution is proposed.We show a general method to achieve dynamic dissipation control by using the toe point mediated chain replacement strategy.Through reasonable redesign of the traditional chain single displacement reaction,the fuel chain continues to participate in the reaction,decomposes into low-energy waste through the energy dissipation in the reaction process,and spontaneously recovers to the original state of relative equilibrium over time.On this basis,a DNA dynamic nanodevice capable of autonomous driving was constructed,and in-depth applications of instantaneous labeling and cascade reaction control of DNA structure were completed.