Construction Of DNA Walking System For RNA Detection,Bioimaging And Gene Therapy

A variety of tumor markers are widely used in the field of disease diagnosis,DNA signal amplification methods,such as DNA walker,can be explored to detect tumor markers with high sensitivity,but still facing many challenges.For example,the spatio-temporal resolution is relatively low,and it is urgent to improve the spatiotemporal accuracy on the basis of the improving sensitivity;At present,DNA walker is mainly used in clinical diagnosis of diseases,but their application in the treatment of intelligent diseases is rarely reported.Therefore,it is vatal to construct a therapeutic platform for the amplification of endogenous tumor markers with high spatial and temporal accuracy to promote the development of disease diagnosis and therapy;The reaction efficiency of traditional DNA walker is relatively low and generally requires several hours to complete.Therefore,new methods need to be developed to improve the reaction kinetics of DNA walker.In this research,we explore UV-sensitive PC group(o-nitrobenzyl)as the photocontrol element and combine with DNA walker to achieve high spatial and temporal imaging and therapy of tumors.By adding a new type of accelerator,we improve the reaction efficiency of DNA walker and enhance its reaction kinetics.The reseaches are as follows:Chapter 1 OverviewThis chapter mainly introduces the advantages,design principle and biological application of the light-controlled activation probe probe.In addition,the classification and application of DNA walker are also described.Finally we expounds the research content and significance of this paper.Chapter 2 Construction and Application of NIR light activated programmable DNA nanodevice in mRNA imaging and gene therapyIn this chapter,an intelligent NIR light-launched and programmable DNA nanodevice is constructed for amplification of mRNA imaging and gene therapy.Upconversion nanoparticles(UCNPs)are used as the carrier of DNA probes and optical transducers.By inserting PC group into DNA as optical control elements,under the excitation of NIR light,UCNPs converts NIR light to UV light,and the cleavage of the PC group triggers a subsequent DNA walker reaction,The nanodevice was successfully applied to accurately spatio-temporal resolution imaging of survivin RNA in living cells,and amounts of antisense oligonucleotide Bcl-2 ASOs was released during the reaction,which was used to silence the corresponding mRNA in cells,inhibit the expression of anti-apoptotic proteins,and achieve gene therapy,thus restraining tumor growth.Chapter 3 DNA walker with high response dynamics for intracellular microRNA imagingIn this chapter,the constructed DNA walker system is used for the detection and imaging of intracellular miRNA.Moreover,a cationic graft copolymer PLL-g-Dex is synthesized,which spontaneously interacts with DNA to form polyelectrolyte complex.By reducing the entropy negative anti-ion condensation effect,decreasing the energy barrier associated with the break and re-dissociation of nucleic acid base pairs to promote the formation of intermediates to accelerate the reaction,the reaction kinetics of the DNA walker is greatly improved,thus realizing rapid and sensitive imaging of microRNA in living cells.