DNA Array System Based On Electrical Detection Of DNA Hybridization

Few scientific areas have been developed so fast as DNA detection and diagnostics has in recent years. With the completion of Human Genome Project, it has provided vast information for DNA detection. Among the numerous DNA detection methods, DNA sensors was intensively developed due to its superior characteristics of easy operation, low costs, fast detection, small size etc.The purpose of this work is to develop a DNA detection system based on electrical detection. Such a system could incorporate the DNA hybridization part and signal collection part into one single chip, with the advantages of high sensitivity, perfect selectivity, small size etc. The application area of this method could be disease detection, biological identification and so on. The major contributions of this thesis are giving in the following aspects:1. A systematic research has been done to optimize the DNA immobilization and hybridization procedures. Based on this work, we proposed an optimized protocol to ensure the high quality hybridization results. 2. A simple and universal method has been designed to amplification the electrical signal of DNA hybridization. This method is based on the multilayer assembly of gold nanoparticles and the following silver enhancement. After the amplification, the electrical signal increased for at least 3 orders without affecting the selectivity. The selectivity of perfect matched DNA and single base mismatched DNA has been enhanced to 109:1. 3. A strategy has been developed to measure multiple PCR products with one or two kind of gold nanoparticles based on our electrical detection methodology. This improvement would help to apply the electrical detection to measure a large number of targets without significantly increasing the costs.4. Two standard photolithography compatible methods have been successfully used to fabricate arrayed micro size DNA detection area. It provides the potential to fabricate high density DNA array and increase the detection sensitivity.5. A high-density microelectrode array has been fabricated by using a standard CMOS process. We have demonstrated the possibility of producing an integrated device based on our electrical detection method for DNA detection.5.