| Modern medical science and life science research results show that a lot of serious disease is closely related to gene mutation, such as cancer, genetic disease etc.Thus, specific sequences of DNA testing and analysis in the determination of pathogenic genes, early diagnosis and treatment of genetic diseases is of great theoretical significance and valuable. In recent years, a series of rapid and reliable specific sequences of DNA detection technology developing rapidly. Nucleic acid detection has been widely applied in molecular biology, modern medical science,clinical diagnostics and many other fields. In this paper, taking mass spectrometry as the detection tool, combining magnetic beads’ enrichment and separation properties,coupling with effective method, such as nucleic acid amplification technology, we develop a series of analysis schemes for cancer related DNA sequence, mainly including the following parts:TK1 m RNA is associated with cell division, it is one of the important markers of tumor growth. Identifying the change of TK1 m RNA in the level of genes in living cells is of great value for understanding biological processes and mechanisms of disease. It’s also becoming more and more indispensable for cancer detection,prevention and treatment. In chapter 2, we develop an isothermal hybrid chain amplification technique based on lanthanide ions tag and used for the examination of TK1 m RNA. In view of the advantages of HCR method and the feasibility of the rare earth ions DNA markers, this topic is based on HCR signal amplification, combining the hybridization mechanism of rare earth ions marked DNA and the complementary DNA with the use of high sensitive detection of ICP-MS to achieve the sensitive detection of DNA. The test platform mainly includes the following several aspects: 1.Referring to the literatures of reported synthesis methods, we get the DNA probe marked with rare earth ions. 2. We achieved the detection of target DNA with the use of enrichment and separation of magnetic nanoparticles and HCR signal amplification method. 3. Using ICP-MS to examine the intensity of rare earth ions in the samples,so as to realize the indirect detection of target DNA. This method comprehensively make use of the operative features of HCR : the constant temperature and signal amplification without enzyme, high specificity of DNA aptamer and the advantages of high sensitivity, high resolution, good stability and strong anti-interference of ICP-MSto realize the specific detection of the target DNA sequence.DNA methylation is an important epigenetic mechanism which involved in gene regulation. It can realize the regulation of gene expression by affecting the conformation and the stability of DNA, the interaction with protein. The Cp G island methylation is probably the earliest research in one of the change of somatic cell genome in several kinds of cancers. Many scientists report the methylation of abnormal phenomenon in different kinds of cancers. It has become one of the biomarkers for a variety of tumor diagnosis. So the analysis of DNA methylation is of vital value for understanding the impact of epigenetics. In chapter 3, we make the use of the function of magnetic beads’ enrichment and separation, take prostate tissue cells as test object, directly apply the electrospray mass spectrometry to achieve the purpose of detecting DNA methylation. The design principle of this method is simple.It’s also of high sensitivity, good selectivity and suitable for the analysis of real samples. |
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