RNA Imaging And Functional Regulation Based On Light-up Aptamers

RNA,as an essential small molecule for the transmission of genetic information in cells,participates in many intracellular physiological activities.Then there are still significant challenges in exploring the function of intracellular RNA and its dynamics.Conventional detection methods usually have high background,low sensitivity,high cytotoxicity and other shortcomings,so designing an excellent tool that can help RNA in vivo imaging is the research direction of many researchers.Fluorescent probes are used in microscopy in modern science.A necessary means to detect small molecules at the level,especially organic fluorescent probes,is editable.The organic fluorescent probes can change the optical properties by changing the position and structure of the functional group on the design of the dye organic small molecule.On the other hand,as a single-stranded DNA or RNA sequence,an aptamer can form a secondary or tertiary structure that specifically binds to a target molecule.Since its proposal,it has been used in biochemical analysis,biosensing,drug discovery,etc.Many significant results have been achieved in the field.PDT(photodynamic therapy)has been recognized as an advanced cancer treatment method and has a series of advantages compared with traditional therapies.In PDT treatment,tumour cells can be killed by ROS(reactive oxygen species)to achieve a cure.However,due to ROS's high reactivity and short-lived nature,this treatment method has a high degree of local impact.However,it will not cause extensive damage to surrounding healthy cells,so a fluorescent probe is used to construct a new ROS photosensitizer is helpful to the research of new cancer treatment.This paper mainly carried out the following work:1.According to the reported literature,some specific aptamer structures can specifically bind to organic fluorescent probes.Therefore,two quenching fluorescent probes are designed in this paper based on this principle.Furthermore,these probes can combine with different aptamers,one is a fluorescent probe based on contact quenching(FITC-DN),and the other is a fluorescent probe based on Stokes' s shift quenching(SR-BHQ1).Then the absorption spectroscopy and fluorescence spectroscopy were analyzed,and the results proved that the two have a good comparison.In addition,by transfecting two plasmids constructed based on RNA aptamers into cells,two different nucleic acid aptamers can be simultaneously imaged.Thus,dual-channel fluorescence imaging provides a way to study the interaction between other RNA molecules.2.According to the reported literature,the introduction of heavy atoms into the structure of organic fluorescent probes can generate reactive oxygen species under specific light conditions.Therefore,we designed a quenching fluorescent probe SR-2Ibased on the structure of rhodamine.DN hopes to explore the changes in fluorescence signal and the rate of ROS generation after combining with SR-2I-DN by introducing aptamers SRB and DNB.The results show that when SR-2I-DN's autofluorescence is quenched,many reactive oxygen species are produced.Still,when combined with the aptamer,the fluorescence signal is restored,but the production efficiency of reactive oxygen species decreases.The aptamer regulates the functional probe.The needle needs to be further optimized.