Construction Of Photoactivated Biosensing System For Detection And Imaging Of Intracellular Potassium Ions And MicroRNA

To understand biological functions,develop and screen drugs,it is very necessary to develop fluorescent biosensors with high temporal and spatial resolution to research the dynamic level of targets in complex biological systems.Although numerous novel sensors have been developed,there are still some challenges to overcome.For example,the probe will specifically recognizes the molecule before they reach the intracellular specific position,which leads to the poor accuracy of the result and low signal-to-noise ratio.Therefore,in this research,we employ the UV-sensitive PC group as the lightactivated element,and successfully developed a sensor to detect and bioimage the intracellular potassium ions after UV light irradiation and a DNA walker to sensor intracellular micro RNA under near-infrared light irradiation.The researches are as follows:Chapter 1 OverviewThis chapter is briefly described the advantages of the photoactivated nucleic acid probe,several kinds of photoactivated probe molecules,photoactivated principle and their application.Besides,the research content and significance of the paper are described.Chapter 2 UV-activated G-quadruplex DNA Probe for Spatiotemporal Detection and Bioimaging of Intracellular Potassium IonsIn this chapter,we construct a UV-activated G-quadruplex probe for the Spatiotemporal detection of intracellular potassium ions and its biological imaging.In this system,a complementary strand was employed to prevent the G-quadruplex probe from potassium ions,and UV-activated PC groups was embedded in the complementary strand to photoactivated the probe with UV light.Under the UV light irradiation,the complementary strand at specific sites was broken and the G-quadruplex probe was released,followed by specific recognition of potassium ions to realize the detection and bioimaging of intracellular potassium ions.The sensor has been successfully used to detect intracellular potassium ions activated by ultraviolet irradiation with high spatiotemporal resolution.Chapter 3: Near Infrared Light Activated DNA Walkers for the Spatiotemporal detection and bioimaging of intracellular micro RNAThis chapter constructs a NIR photoactivated DNA walker system powered by endogenous ATP for the bioimaging of in-situ intracellular mi RNAs with high spatiotemporal resolved.We employed upconversion nanoparticles(UCNPs)as DNA probe carriers and light converters,and use UV-sensitive PC groups as light-controlled elements.Under the excitation of near-infrared light,UCNPs convert NIR to UV,and PC groups are cleaved to trigger subsequent DNA walkers.The sensor has been successfully applied to accurately spatio-temporal resolved imaging of intracellular mi RNA in living cells.