| In this thesis, We construct a novel, rapid and sensitive detection method for DNA based on bio-barcode technology by electrochemical analysis, and realized accurate and effective detection of Escherichia coli DNA, Salmonella DNA, Shigella DNA at the same time. The main contents are as follows:(1) The difference in electrochemical behavior between G-rich DNA and ordinary DNA were researched in the first work. A comparative study on the four types of DNA in the electrochemical behavior such as ordinary single-stranded(ss-DNA), double-strand DNA(ds-DNA), single and double-strand G-rich DNA. A gold nanoparticles array electrode was made by electro-deposition technique, which was found not only could efficiently improved the electrode response signal, but also could keeping the stability of the electrodes. The result indicate that this method can easy and efficiently realize the detection of target DNA sample, as well as distinguish oligonucleotides of which have difference in their base type.(2) The Escherichia coli gene sequences and the target DNA molecules were determined based on the literatures and the related database, and disigned the DNA probes. The analog computation is carried out based on professional software, for checking the feasibility of the desiged DNA probes. The detection of Escherichia coli DNA was simply realized with the improved two step method by the amplification technique using bio-barcodes and gold nanoparticles.(3) Determining the characteristic gene sequences and the target DNA molecules of Salmonella and Shigella based on the literatures and the related database, and then disigned the DNA probes. The analog computation is carried out based on professional software, for checking the feasibility of the desiged DNA probes. A novel detection method was constructed by label-free direct electrochemical analysis for multiple targets containing the feature DNA molecules of Escherichia coliforms, Salmonellas and Shigellas. |
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