New Diagnostic And Therapeutic Methods Based On Functional Nucleic Acids And Nanomaterials

With the rapid development of the society,people pay more attentions to the field of life science.People have studied the law of life activities,the mechanism of action and the interaction between organisms on the molecular level,and achieved great progress in the prevention,early diagnosis and treatment of diseases.The traditional methods for diseases diagnosis and treatment cannot track the disease location in real time and reflect the treatment effect.How to realize the effec tive detection of diseases and how to combine the diagnosis and treatment,are still problems to be solved.This paper fully combines the advantages of molecular imaging,the characteristics of functional nucleic acids and the superior properties of nanoma terials,to design a series of methods for sensitive detection of cancer markers such as telomerase and miRNA.Further,the technology of combinative diagnosis and treatment,was used to effectively treat diseased cells,avoid damage to normal cells,and p rovide a universal platform for accurate diagnosis and treatment.The detailed research contents are as follows:In order to effectively detect the disease.In chapter 2,considering the complexity,time-consuming and low sensitivity of the existing method s for detecting telomerase,we proposed a method of combining telomerase primers,molecular beacon probes and metal-organic framework ZIF-8.In the presence of telomerase,the extension sequence of primer can turn on the molecular beacon to realize the rap id recovery of fluorescence signal and in-situ detect the telomerase of living cells.In chapter 3,we designed a ratio fluorescent probe based on DNAzyme for solving the problem of the higher background fluorescence in cells.ZIF-8 as a probe delivery carrier,would degrade in tumor acid lysosome and release the probe.At the same time,the released zinc ions can be used as cofactors for 8-17 DNAzyme and activate the substrate cutting by DNAzyme.Subsequently,miRNA-21 hybridized with partially split substrate and leaved,resulting in blocking of fluorescence resonance energy transfer,thus achieving the effective detection of miRNA-21.In chapter 6,according to the dispersed problems of DNA computing systems,we put forward modular DNA calculation based on origami plane,to provide a common platform for the complex DNA logic circuit computing,and designed a He La cell diagnostic system,to realize the simultaneous imaging of multiple miRNA and provide more reliable basis for disease diagnosis.The above methods provided a common platform for early cancer diagnosis.For the effective diagnosis and treatment of diseases.In chapter 5,aiming at the effective delivery of Cas9/sg RNA complex,we designed a CSZ delivery system,mainly by metal organic framework material ZIF-8 wrapped Cas9/sg RNA complex.The CSZ system transported Cas9/sg RNA complex to cells to maintain the activity of Cas9/sg RNA complex and avoid the degradation of Cas9/sg RNA complex in complex physiological environment,thus achieving effective g ene editing.In chapter 4,in response to the serious side effects of traditional treatments on normal tissues,we constructed DNA-MnO₂ nanodevices to achieve the synergistic effect of telomerase-activated photodynamic therapy and gene silencing for the pr ecise treatment of cancer cells without damaging normal cells.The activation diagnosis and treatment provided a valuable and general platform for personalized accurate treatment of cancer cells.