Study On DNA Fluorescence Sensor Array Based On Hybridization Chain Reaction

Fluorescent biosensor array has good application potential in clinical disease diagnosis and treatment,gene analysis,environmental monitoring and so on.It can detect biomolecules economically,quickly,sensitively and specifically.The similarity of most nucleic acid molecules are high and it is difficult to distinguish them.It is an important problem to be solved in analytical chemistry.In addition,the construction process of some fluorescent sensor arrays is complex,and it takes a lot of manpower and material resources.In order to solve these problems,we constructed three kinds of DNA fluorescence sensor arrays,using the entropy-driven amplification reaction of the enzyme-freesignal,to distinguish effectively many kinds of nucleic acid analogues.Moreover,this method has the characteristics of strong generality and high sensitivity.In these sensor arrays,we investigated the cross-reaction of hybridization chain reaction,and realized the distinction and recognition of DNA,RNA and gene expression profile.The contents of the study are as follows:(1)The application of DNA fluorescence sensor array in drug-resistant genes:This chapter designed a cross-reactive DNA circuit sensor array that uses hybridization chain reaction and entropy-driven signal amplification to distinguish and recognize six HBV-resistant genes.The DNA sensor array has high sensitivity and the detection range is 1 nM-20 nM.Through gel electrophoresis and fluorescence detection,we have verified that the sensor array is rich in cross-reactivity.The feasibility of hybridization chain reaction and entropy-driven signal amplification are verified.After optimizing the sensor array,the DNA sensor array can be reduced to four groups of sensor elements,but it is still possible to distinguish six target DNAs,indicating that the sensor array has good analytical performance for six HBV-resistant genes.In addition,the fluorescence sensor array can effectively distinguish different systems,including two different ratios of target DNA mixture,different concentrations of the same target DNA,and six target DNAs in a complex system.These results demonstrate that fluorescence sensor array designed by us has good anti-interference ability and practicability,showing the value in bioanalytical applications.(2)The application of DNA fluorescence sensor array in RNA:This chapter designed a cross-reactive DNA sensor array that uses hybridization chain reaction and entropy-driven signal amplification to identify four RNAs(Let-7 family).The target recognition region of the DNA sensor array is separated from the signal amplificationregion,therefore,each group of sensing elements has the same influence on the entropy-driven amplification reaction and has strong versatility,and the detection range is 2 nM-20 nM.Through gel electrophoresis and fluorescence detection,we have verified that the sensor array has rich cross-reactivityand can effectively distinguish different systems,including two different ratios of target RNA mixture,different concentrations of the same target RNA,four target RNAs in a complex system,and target RNA gene expression profile.(3)Application of multi-dimensional fluorescence sensor array based on cooperative hybridization: This chapter designed a DNA sensor array based on multiple cross-reactions,using cooperative hybridization,hybridization chain reaction and entropy-driven signal amplification reaction to distinguish and recognize five kinds of single base mismatch DNAs.Through gel electrophoresis and fluorescence detection,we have verified that the sensor array has multiplex cross-reactivity.These results show that the fluorescence sensor array designed by us has a good universality and provides a new way to distinguish and recognize similar targets.In addition,based on the two types of hybridization chain reactions designed in the first two chapters,we constructed a new DNA fluorescence sensor array based on the orthogonality of these two kinds of hybridization chain reactions.The fluorescence sensor array realized the differentiation of gene expression profiles composed of different concentrations of DNA,RNA,and it shows the value in distinguishing different types of target.