The Construction Of Novel Fluorescent Probes And Thier Application In The Detection Of Biomarks

Biomarkers are indicators that can determine the occurrence,development,and prognosis of diseases.Biomarkers cover a wide range of biochemical entities,including nucleic acids,carbohydrates,proteins,enzymes,active molecules,and tumor cells found in the body.Moreover,they are often used in the diagnosis and classification of diseases,monitoring the development of the disease,as well as testing the clinical treatment effect.Therefore,establishing an accurate,sensitive,real-time method for the detection of biomarkers plays an immeasurable role in the early,rapid and accurate diagnosis of disease.Fluorescent technique with its intrinsic advantages such as high sensitivity,real-time detection,high spatial resolution imaging in live samples,and good biocompatibility,has recently emerged as an efficient tool.In this paper,four kinds of novel fluorescent probes have been designed and synthesized for the rapid,sensitive and selective detection of glutathione(GSH),y-glutamyl transpeptidase(GGT)and alkaline phosphatase(ALP)in living cells(or in vivo),respectively.Firstly,a rhodamine-based fluorescent probe(Rh-COOH)with high water solubility by structural modification is constructed.A carboxyl group is introduced to the chemical structure of the probe to improve the water solubility of rhodamine-based fluorescent probe,which makes it operates well in aqueous solution without organic solvent.Moreover,the probe exhibits high sensitivity toward GSH with 69-fold fluorescence enhancement.In addition,the probe can distinguish GSH from Cys and Hey based on an addition-hydrolysis reaction between SH of GSH and the aldehyde of the probe.Most importantly,the probe can effectively discriminate GSH from other biological thiols and amino acids in living cells.Secondly,by utilizing the change in the conjugated ?-electron system of the fluorophore,a near-infrared ratiometric GGT fluorescent probe(Cy-GSH)with high water-solubility is designed and synthesized.GSH is selected as the substrate for y-glutamyl transpeptidase,which makes the probe with excellent water solubility.Moreover,the ratiometric fluorescent probe with remarkable emssion shift can effectively eliminate background interferences,and thus provided enhanced sensitivity.Futhermore,Cy-GSH exhibits NIR emission,which is suitable for monitoring cancer microenvironment in vivo.Most importantly,activated by the overexpressed GGT in cancer microenvironment(such as serum,cells,tissues and tumors),probe Cy-GSH can remarkable differentiation between cancer microenvironment and normal microenvironment.Thirdly,a novel enzyme-responsive fluorescent probe based on solid state fluorochrome is designed for GGT activity assay.HPQ-PDG is water-soluble and can release a precipitating fluorophore HPQ upon GGT conversion.Moreover,the precipitating HPQ shows a spatially isolated and highly localized spots fluorescence signal in live cells with diffusion resistant ability.The successfully applicability of HPQ-PDG detecting GGT activity in mice serum samples shows that the probe holds great potential for being an effective tool for GGT activity detection in clinical samples.In addition,the probe has further been used to monitor the change of intracellular GGT activity under oxidative stress regulated by NaBu.Importantly,all these live cells images show that HPQ-PDG could remarkable discriminating cancer cells from normal cells.What's more,we successfully applied HPQ-PDG for pathological tissues imaging.Finally,taking full advantage of the coordination polymer nanoparticles and organic dyes,a near-infrared(NIR)fluorescent nanoprobe based on infinite coordination polymer nanoparticles(CyOH@Tb-GMP)is constructed for endogenous ALP activity assay.The fluorescence emission of the nanoprobe is at 718 nm belonging to NIR region,which is suitable for bioimaging.In addition,the nanoprobe displays better photostability than common NIR dyes such as ICG as well as CyOH.Moreover,the nanoprobe exhibits high sensitivity for ALP activity with a 7.5-fold fluorescence enhancement when 2.5 U/mL ALP is added.Most importantly,the NIR nanoprobe is employed for monitoring endogenous ALP activity in various biological samples such as cell,tissue and mice with satisfactory results.