Detection Of DNA And Small Molecule Based On Carbon Nanotubes And Au Nanoparticles

Recently, carbon nanotubes and Au nanopaticles have been widely used in analytical chemistry, biology, physics, etc., because of their advantages, such as unique chemical, structural, photonics and mechanical properties, high stability, and good biocompatibility.In this thesis, a series of detection methods were developed for small molecules and double-strand DNA(dsDNA), with carbon nanotubes , Au nanoparticles, and the specific recognition of nucleic acid probes. The main content of this thesis are summarized as follows:(1) Double-stranded DNA detection based on peroxidase-like activity of single-walled carbon nanotubeDNA naturally exists in double-stranded form. Sensitive and accurate detection for double-stranded DNA is significant in biological research and its application. A double-stranded DNA detection strategy was designed in this thesis on the basis of peroxidase-like activity of single-walled carbon nanotube. This assay could realize real time monitoring by UV-vis spectrum without any label,and highly sensitive and accurate detection, with a detection limit of 11.5 nM. This simple and sensitive strategy shows great promising for other biomolecules sensing.(2) Silver(I) ion detection based on fluorescence quenching effect of single-walled carbon nanotubeTrace Ag+ can kill food bacteria in drinking water, but excessive intake will have toxic effects on the human body. A detection method for Ag+ has been developed based on the fluorescence quenching of single-walled carbon nanotubes (SWNTs) and the specifically binding ability of cytosine–cytosine (C–C) and (Ag+). This method only needs one step mixing with a detection limit of 0.6 nM, and could be applied to Ag+ detection in real sample.(3) Coralyne detetion based on Au nanoparticles aggregationCoralyne has good anti-tumor activity and can specifically bind to poly(A). In the presence of coralyne, Au nanoparticles labeled by poly(A) labeled Au nanoparticles are aggregated, resulting in the color and size changes. On this basis, coralyne was detected by UV-Vis specture, resonance scattering scattering and dynamic light scattering. The detection limit could reach 0.19 pM by dynamic light scattering. It offers a normal strategy for drug sensing, and broaden the application of dynamic light scattering.