The Application Of Dna Biosensor Based On The Technology Of Signal Plification

Surface enhanced Raman scattering（SERS） and surface plasmon resonance imaging（SPRi） technology was two highly sensitive detection methods which had emerged in recent years. The advantages of simple operation, fast response and high sensitivity had made them rapidly develop.This thesis combined the two kinds of novel detection method with hybridization chain reaction,polymerase chain reaction cycle amplifying technology and nano materials technology, building several analysis method which could effectively detect metal ion and protein.The content was mainly described as follows:1、A surface enhanced Raman method of detection mercury ion was designed,which was based on target mercury ions causing hybridization chain reaction and the amplification of nano biological barcode technology.First, Thymine-mercury-thymine specific binding function introduced the target molecules Hg²⁺.then,hybridization chain reaction provided a large number of sites for the combination of the Raman signal molecule and nanomaterials in biological barcode,which guarantee the adhesion of a large number of signaling molecules.last,the strong interaction of streptavidin-avidin binded the signal molecules into the magnetic beads.So,we could realize effective detection of Hg²⁺ by detecting the intensity of the Raman signal molecule binding on the magnetic beads.This method was validated to be a novel,simple, innovative tool, providing a new promising platform detecting Hg²⁺ in environment.2、A surface plasmon resonance imaging method detection of Hg²⁺ was designed by combining biological nanometer materials and hybridization chain reaction.The special structure of the T-Hg²⁺-T combined two mismatches DNA with Hg²⁺.the hybridization chain reaction and biological nanometer materials could amplify the signal with the effect of coupling effect and weight effect.So we could enhance the signal value of SPR and detection limit of 1.0×10-10 M was achieved. This method realized the rapid,effective and high sensitivity detection of Hg²⁺, providing a new way for detecting heavy metal ions.3、SPRi detection of thrombin was proposed by using the amplification effect of thepolymerase and biological nano-materials surface enhanced plasma effect. We developed a strategy for thrombin detection by combining thrombin with the specific aptamer and converting the quantitative thrombin to the DNA.In the experiment hairpin DNA and S1 biometric function ensured the specificity and selectivity of the experiment. The introduction of the gold nanoparticles and quantum dots could undertake coupling effect and enhanced signal. DNA polymerase could amplify the signal by a series of repeated polymer displacement reaction.So the application of multiple amplification reaction could achieve the effective detection of thrombin.The experiment scheme was simple, economic and widely applicable.If we change the specific interaction of the aptamer and thrombin into other recognition function,it could be widely used in the detection other small molecule protein.