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Signal Enhancement For Biosensors Based On DNA Self-Assembly

Posted on:2012-11-21Degree:MasterType:Thesis
Country:ChinaCandidate:J Q ZhuFull Text:PDF
GTID:2248330371963414Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
DNA has attracted increasing attention because of facile synthesis, easy modification, stable properties and its specific Watson-Crick-based duplex. In addition, DNA has plenty of self-assembled structure, good biocompatible and variety of characterization methods. Recently, the sensitivity and selectivity have been improved by combining DNA self-assembled structure and variety of traditional bioanalysis technology. Based on DNA self-assembled structure and gold nanoparticles, in this thesis, three kinds of signal amplification approaches for detection of DNA and small molecules were demonstrated, respecitively. The main researches of this dissertation are summarized as follows:1. An electrochemical biosensor for adenosine based on“supersandwich”signal amplification. A DNA self-assembly-based“supersandwich”structure has been employed for adenosine detection. The detection limit of the method for adenosine is 50 nM. The strategy has improved the detection limit for nearly 10 times compared to“non-supersandwich”method. It is an enzyme free, label free, simple, inexpensive, and good generality detection method.2. An electrochemical biosensor for DNA amplified detection based on dendritic DNA-capped gold nanoparticles. Through repeated“sandwich”format, two different kinds of DNA-capped gold particles have been used to build dendritic architectures on the surface of electrode for DNA quantitative detection. The detection limit is 0.13 pM. The strategy has improved the detection limit for nearly 4 times compared to“gold nanoparticle-only”method. The approach possesses high sensitivity, excellent selectivity, reproducible properties, and good generality.3. A SPR DNA sensor based on gold nanoparticles and“supersandwich”signal amplification.First, the SPR response signal was enhanced by electronic coupling between gold film and gold nanoparticles. Then, the signal was further enhanced by“supersandwich”format of DNA-capped gold nanoparticles. After twice amplification processes, the detection limit is 0.1 pM. It has improved the detection limit for nearly 100 times compared to“gold nanoparticle-only”method, which is expected to expend to other targets detection...
Keywords/Search Tags:Gold nanoparticles, DNA self-assemble, Electrochemical, Surface plasmon resonance
PDF Full Text Request
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