.chitosan / Sio <sub> 2 </ Sub> Composite Nanoparticles And Dna Interactions And Analysis Of Applied Research

DNA bionesor, based on DNA interation or other biological reaction, is a new kind of bionesor with the advantage of a simple, rapid and high sensitivy operation procedure. It has far-reaching significanceand applicable value in the study of clinical medicine and genetic project and has gradually become an important field in the study of molecular biology and biological research. The preparation and characteristics of these sensor, the recent research advances of elements of biosensor construction, classification and applications involved are reviewed. The prospects of biosensor are also presented.Nanotechnology is playing an increasingly important role in the development of biosensors. Because the Nano-materials, with their size in the range of 1-100nm, are currently under intense investigation owing to their special properties. This dissertation focuses on fabricating novel DNA biosensors by use of the nanocomposite and with the method of fluorescence, thus developing a sensitive, quantifiable gene detection method, and establishing the bases for application of the DNA biosensor to clinic diagnose. The contents and results of research in this thesis contain the following two parts:1. The synthesis of biocompatible Chitosan/SiO2 nanocomposites and it's application for DNA adsorptionA novel mesoporous chitosan-silica nanoparticles was synsized with the water-in-oil (W/O) reverse microemulsion method. By characterizing this nanocomposites with transmission electron microscopy, IR spectra and the zeta potential experiments, it was found that this nanoparticles are spherical and uniform with 50nm size and presented the mesoporous structure. Based on these findings, the adsorption ability of this nanocomposite for calf thymus DNA was studied. The relating results showed that this nanocomposites has a stronger adsorption ability to DNA in PBS buffer, it also presented the better biocompatibility for cell and can be used for protect DNA from DNase I-cleavage.2. The design of DNA biosensor based on lucigenin-Chitosan/Si02 Mesoporous nanocomposites and it's bioanalytical application for sensing DNAIn this part, using the reverse microemulsion method, the mesoporous, fluorescenct nanocomposite of chitosan with silica was synthesized. It was found that the mesoporous nanocomposites showed the stronger adsorbed ability for the DNA probe, and can be further used to sense the target DNA with the fluorescence quenching effect of the doped lucigenin and the fluorescence experiments indicated that detection sensitivity at the naomole level has been successfully demonstrated, further more single-base mutation in the target DNA sequence has been differentiated, which makes it promising for biomedical and bioanalytical applications requiring high-performance genetic target analysis. Finally, based on these findings, a label-free, multiplexed DNA assay in a solution-array format using the self-assemble nanocomposite as the detection transducer for sensoring DNA has been described. The major advantages of this assay are its speed, simplicity, excellent specificity, and convenience.therefore, provide the groundwork for the design of other nanodevices for biosensing applications and the concept can be expanded to monitor other molecular interactions where DNA binding is involved.