Study On The Novel DNA Signal Amplification Methods Based On Enzyme And Gold Nanoparticle

DNA has a wide range of applications in the construction of biosensors and functional nanomaterials. DNA signal amplification is commonly used to establish highly sensitive analytical techniques, especially for the detection of trace analytes. With special properties or structures, metallic nanomaterials are often associated with DNA to design novel sensors and develop functional nanomaterials. For example, gold nanoparticles have been widely used in the design of biosensors owing to the unique optical properties.DNA technology plays an important role in the field of analytical chemistry due to various forms of signal amplification. Traditional DNA signal amplification methods, such as Polymerase Chain Reaction (PCR), depend on the thermal denaturation, enzyme and the necessary instruments to achieve the amplification of targets. These traditional methods are difficult to meet the development of rapid, simple, and easy to operate, easy to observe analytical techniques. Therefore, it is particularly significant to study new, isothermal, and enzyme-free DNA signal amplification methods. In this paper, we constructed two kinds of novel DNA signal amplification methods based on enzyme and gold nanoparticles.First, we designed a new nucleic acid isothermal amplification method by allying polymerase and nicking endonuclease and applied this method to the detection of miRNA. The detection result revealed a good linear relationship with the target concentration ranging from10-16-10-13mol; we verified the specificity of this method by detecting miRNAs with different sequences; we verified the practicality of this method by testing the target in human serum. Second, we established a novel enzyme-free signal amplification colorimetric method by combining DNA-modified gold nanoparticles with hybridization chain reaction (HCR). In this way, we achieved a sensitive colorimetric detection of target DNA. This method was simple, sensitive and enzyme-free. This method allowed us to detect target DNA with the naked eye in a detection limit of0.5nM.