Polymerase Chain Reaction Based On Nanoparticles

The study of polymerase chain reaction (PCR) based on magnetic nanoparticlewould not only bring the convenience to the detection, isolation and purification ofPCR products but also provide a new method for preparing DNA chip and thenanostructure contained DNA and nanoparticles. In recent year, some literaturesreported that PCR based on solid phase could proceed. But it was an initial study, andstill needed to do a lot of work. In this thesis, we had systematically studied PCR basedon nanoparticle.(1) A thin silica-coating layer encapsulating bare γ-Fe2O3 nanoparticles wasformed by a base-catalyzed hydrolysis and polymerization reaction of tetraethoxysilane(TEOS) in reverse microemulsion. The experimental results show that the structure ofcore-shell is successfully synthesized and the synthesized MNP holds uniform size indiameter and very fine monodispersion in suitable condition.(2) The oligoDNA was covalently immobilized on the surface of MNP bychemical method and a technique of SERS was developed to detect it. Theexperimental results show that thiols attached on Ag substrate have excellent SERS andoligoDNA was covalently conjugated to the surface of MNP by disulfide bond. At thesame time, the fact was also demonstrated that oligoDNA immobilized on the surfaceof MNP still maintain very fine biological activity by hybridization withcomplementary single strand DNA, which is prepared for PCR based on magneticnanoparticles.(3) The law of PCR based on MNP was systematically studied. The experimentalresults show that the primers anchored on MNP can start PCR in suitable condition. Theannealing temperature affects hardly PCR when the forward primer was immobilizedand the reverse one is free, but the annealing temperature affects seriously PCR whenboth primers were immobilized and the purity of PCR products was enhanced with theincrease of annealing temperature in a certain temperature range. At the same time, theexperimental results also show that the MNP/DNA aggregates were constructed byPCR in which both primers were immobilized on the surface of MNP.