Design, Synthesis And Application Of Novel Fluorescent Probes Based On Tetrastyrene And Polyfluorene Derivatives

There are many active small molecules in cells, which are crucial for cell and organism. For example, hydrogen sulfide is an important signal molecule, which closely associated with a variety of physiological processes, including antioxidant, against ischemia-reperfusion injury, and apoptosis, etc. In addition, sialic acid glycans as tumor markers, gradually known by others, and studies found that sialic acid glycans mainly exist in the outer of cell membrane or in the blood. And sialic acid glycans content increased when life body inflammation and tumor. Therefore, to develop new fluorescent probe for monitoring of hydrogen sulfide and sialic acid glycans is of great significance to reveal the occurrence and development related diseasesBased on the above points, we did the following works:1. A dual signaling molecule sensor has received increasing attention owing to its ability to read out targetanalytes with more than one transduction channel and thusmake the results more convincing. Here we have developed adual signaling molecule sensor that is well suited for monitoring hydrogen sulfide(H2S) levels through fluores-cence, UV-visible adsorption, and visual mode. Results showed the selective and instantaneous responses of sensor toward intracellular H2 S. Moreover, the sensor was successfully applied to imaging of H2 S levels in Caenorhabditis elegans(C.elegans) and observed the changes of H2 S under starvation of C. elegans. Altogether, the sensor was proved to be a useful tool fortracking H2 S levels in cells and in vivo. The merits of two kinds of independent signaling molecules allow us to select different output modes according to the different samples.2. A fluorescent nano probe with polyfluorine as core, combined with molecular imprinting technology, that specifically recognized sialic acid was designed and synthesized. Sialylated glycans has been found correlate with the occurrence of diverse diseases and it has been used as biomarkers in clinical diagnostics. Although fluorescence probe has proven to be a useful tool for cell surface glycan analysis, but background interference caused by auto-fluorescenceis still a problem, moreover, for in vivo imaging, the ideal probe requires not only low background interference, but also have deep tissue penetration ability. Herein, we have developed a two-photon fluorescent nanoprobe based on sialic acid imprinted conjugated polymer and boronate affitity, which is well suited for monitoring cell surface glycan selectively. Results showed that the recognition performance of the nanoprobe for SA. And the nanoprobe has been successful application in imaging of sialylated glycans in cell. Further more, the probe was successfully applied to distinguish the difference on sialylated glycans level between normal and tumor tissues in mice via two-photon imaging owing to large absorption cross section 563 GM. The present study provides efficient fluorescent tool for imaging of sialylated glycans in cells and in vivo.