Manufacture And Application Of DNA-Quantum Dots Biofunctional Materials On Cancer Celluar Imaging

DNA, the carrier of life's genetic information, has been recognized as a versatile biofunctionalized material for constructing self-assembled structures on the nanoscale. Structural DNA nanotechnology just uses DNA as a blue print and building material to organize matter with nanometer precision. By this method, the prepared DNA nanostructure and bio-nano materials have not only a good nano effect but also biological compatibility ,which have been widely applied in many different fields such as modern biology, medicine and life science. The thesis focus on DNA nano structure and DNA bio-nano materials design, preparation, assembly and discuss their application in the cell imaging testing. The major contents of the thesis are as follows:1 We carried out the preparation and research about a novel extracellular supramolecular reticular DNA-quantum dot (QD) sheath. The extracellular supramolecular reticular DNA-QD sheath is constructed from layer-by-layer self-assembly of DNA-CdTe QD probes and DNA nanowire frameworks functionalized with Ramos cell-binding aptamer. fistly, We synthesized the water-soluble CdTe QDs to get the DNA-CdTe QD probes. Secondly, we used several palindrome single-stranded DNA and cell-binding aptamer to form the DNA nanostructure, which make DNA form three-dimensional reticular structure with repeat units. At physiological temperature we mix them to get a large number of extracellular supramolecular reticular DNA-quantum dot (QD) sheaths. A very high fluorescent intensity were observed by fluorescence microscopy imaging. What's more, This kind of functional materials can be stored for long time.2 In the present study, we present a novel cage-type cellular probe for the rapid qualitative analysis and the sensitive quantitative analysis of Ramos cells. Owing to the good affinity and selectivity of cell-binding aptamer for its target cell, supramolecular reticular DNA-QD sheath on the surface of Ramos cells, the supramolecular reticular DNA-QD sheath on the surface of Ramos cells, provides much higher fluorescence intensity than that of usual cell labeling method in cellular imaging. To achieve accurate quantitative analysis of Ramos cells, a sandwich-type assay is constructed using Ramos cell-binding aptamer-immobilized polystyrene microwell plates to capture Ramos cells and then assembling the supramolecular reticular DNA-QD sheath on the surface of Ramos cells. A sensitive differential pulse anodic stripping voltammetry (DPASV) detection system is used to quantify the concentration of CdII produced by the acid dissolution of DNA-CdTe QD probes. Ramos cells can be detected with a limit of 10 cells.3 We designed a new flexible DNA network material, which wrapped the cell surface. Because of the CdTe introduced makes elastic DNA materials emit visible fluorescent. The Ramos cell with surface wrapped by this elastic DNA functional network materials, can be observed in fluorescence microscopy. Through the observation primarily validated the feasibility, and through the parcel of the elastic network materials, realizing the goal of using fluorescence imaging to simplify the process of life activity of cancer cells.