The Designs Of DNA Electrochemical Biosensors

With the implement of Human Genome Plan, gene diagnose has become an important area of molecular biology and biomedical research. The detection of specific DNA sequence in human body virus and bacteria nucleic acid is playing a more and more important role in disease diagnose food pollution legal medical examination and environment detection. Wide-scale genetic testing requires the development easy-to-use, fast, inexpensive, miniaturized devices.Faradic Impedance Spectroscopy is a useful tool for investigating electrode process. It can provide a lot of information, such as resistance, capacity and inductivity. It holds the advantage of sensitive, fast-testing and free-labeled.Moreover, in order to meet the increasing demand of protein analysis, various methods have been developed. The traditional technique is based on the specific interaction between antibody and antigen. However, DNA aptamer, a specific DNA sequence which can recognize protein like antibody/antigen, is being attracted much attention to fabricate novel protein biosensors. There are many evident advantages of DNA aptamer: it is artificial so it can be modified with all kinds of functional group (such as fluorescence group); it can be easily immobilized and detected; and the dynamic parameter can be modified as required.This paper combines the principle of base-complementary, Faradic impedance Spectroscopy and the specific recognition of certain protein to design electrochemical DNA biosensors with high sensitive and unique selection. They can not only detect DNA of specific sequence, but also can recognize corresponding protein molecular, as a result, it should broaden the research field of post-genetic time.Chapter 1 The review of DNA biosensorsIn the beginning of this dissertation, the basic composition of a DNA biosensor and its classification are systematically reviewed, especially the design of a DNA electrochemical biosensors, such as the immobilization of ssDNA onto electrode, hybridization and signal conversion. Then the basic theory of Electrochemical Impedance Spectrum is introduced, together with the application and development in DNA biosensor. Finally, the concept of aptamer, and the application and its current research are introduced.Chapter 2 Electrochemical DNA Biosensor Based on a Thionine-Carbon NanotubeModified Electrode A DNA biosensor based on thionine-carbon nanotube modified glassy carbon electrode is...