Study Of Electrochemical DNA Biosensors Based On Electrochemical Impedance Spectroscopy

With deeply understanding the structure and function of human gene, gene diagnostics has now played an important role for human disease cure. As a result, detecting specific DNA sequences in human, viral, as well as bacterial nucleic acids is of great significance, and calls for an easy-to-use, inexpensive and miniaturized device for speedy gene analysis with practicality. Among the developing gene analysis technologies, DNA biosensor, which is based on base-pair rule, is studied deeply these years, including the electrochemical one. The electrochemical DNA biosensor is relative to biochemistry, electrochemistry, medicine and electronics, etc., transducing the hybridization reaction into a readable electrochemical signal. For its sensitivity, speediness in detection, low cost, easily being miniaturized, as well as independence of the sample turbidity, electrochemical DNA biosensing is speedily developing for DNA sequence analysis.Electrochemical Impedance Spectroscopy or EIS is a powerful technique for the characterization of electrochemical systems. The promise of EIS is that, with a single experimental procedure encompassing a sufficiently broad range of frequencies, the solution resistance, double layer capacitor, electronic transfer resistance and other electrode-solution interfacial electrochemical characteristics can all be distinguished. Therefore, it is always used to analysis electrochemical processes. It has the virtues of speediness, label-free, sensitivity when using impedance DNA biosensor, which is detecting the changes of DNA modified electrode's interfacial electrochemical characteristics as hybridization signal. Moreover, it has been suggested that EIS is very suitable for studying the electronic transfer through the DNA helix with mismatched base pairs.The dissertation has focused on fabricating impedance spectroscopy-based electrochemical DNA hybridization sensors for sensitive, sequence-specific gene detection. It includes characterizing the direct DNA hybridization detection using...