Fabrication and Electrical Detection of DNA Sensor with Gold Nanoelectrodes

• Main Authors: Chieh-Tso Chen, 陳界佐
• Other Authors: Tzeng-Feng Liu
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/37090241261788546477

碩士 === 國立交通大學 === 奈米科技研究所 === 93 === In recent years, a variety of DNA assay techniques based on electrical detection for diagnosis of genetic and pathogenic diseases had been explored. Among those skills, the major characterizations of detection methods were to avoid the use of polymerase chain reaction for amplifying the concentration of analytic DNA and expensive optical microscope equipments to obtain emitting signals from fluorescent DNA. Herein, I investigated a novel strategy for the electrical detection of DNA by aldehyde-derivatized oligonucleotide probes. In this experimental protocol, we combined the shaped electron beam lithography to fabricate sub-nanometer gap between two electrode pads on silicon wafers, and the gold electrodes were fabricated by lift-off process. 27-mer single-stranded nucleic acids called as capture DNA were immobilized on exposed SiO2 surface modified with amino groups between two electrodes. Then analytical DNA (namely targets DNA) functionalized with aldehyde groups were spotted for occurring specific recognition. After washing with PBS buffer and DI water strictly, the DNA chip was handled with Tollen's reagent acted as oxidation agent. When the sequences of the target DNA were complementary to the capture strand, silver ions would be reduced by the aldehyde groups localized on base within DNA and deposited along with the DNA skeleton. Hence, the complementary double-stranded DNA molecules were metallized by Tollen's reagent and the increased currents across gold nanoelectrodes could be measured by analyzer directly.