Study On The Application Of Nanoparticles As Chemiluminescent Probes In The Detection Of DNA Hybridization And Immunoassay

The detection of DNA hybridization and immunoassay play a very important role in life sciences. They have been widely used in biochemistry, molecular biology and medical diagnostics. With the development of the life sciences, the disadvantage of the routine methods, such as the radioactive assay, enzymatic assay, has already been revealed. Then, it is very necessary to develop new analysis methods with high sensitivity, simple operation and universal applicability.In this dissertation, we studied the applications of metal nanoparticles in the detection of DNA hybridization and immunoassay by using high sensitive chemiluminescence (CL) technique. The results of determination of specific sequence oligonucleotides and human IgG were satisfactory.By using specific sequence oligonucleotide-modified silver nanoparticles as labels, the sandwich-type hybrids can be formed after the hybridization reaction. The amount of silver nanoparticles was proportional to the concentration of target oligonucleotides. When the silver nanoparticles was quantitatively determined by using CL method, the concentration of the target oligonucleotides can be obtained. In this study, the CL intensity is proportional to the concentration of target oligonucleotides in the range of 14 fmol L^-1-1.4 pmol L^-1 and the detection limit (3σ) is 5 fmol L^-1. Moreover, through monitoring the CL response, one can differentiate the one-base mismatched target oligonucleotides and perfectly complementary target oligonucleotides by controlling the hybridization temperature. The results indicated that the proposed CL assay might pave a new way for the SNP analysis.We also developed the CL detection method of DNA hybridization by using gold nanoparticles as labels. The relationship of the CL response and the concentration of target oligonucleotides was obtained in the dynamic range of 0.28 pmol L^-1-14 pmol L^-1, and the detection limit (3a) is 0.1 pmol L^-1. With a further gold nanoparticles-based silver amplification, the sensitivity increased about two orders of magnitude.