Nucleic Acid Probe And Two-photon Fluorescent Probe For Detection Of Small Bioactive Molecule

Life is like a complex factory,and as a complete unit the cell plays an important role in the daily life activities.The active small molecules in the cell such as active oxide species and biothiols are involved in the metabolism through the chemical reaction process.Under a certain level,they can maintain normal organism activity.When its concentration has a great change,it may break metabolic balance or make the physiological disorders,or even cause disease.So their levels in the body are helpful for some disease diagnosis.Considering the importance of the active small molecules,this thesis was focused on the following two aspects works:(1)Pyrene-labeled allosteric probe for time-resolved fluorescent detection of biothiol.Based on the strategies of thymine-Hg2+-thymine(T-Hg2+-T),we designed a novel fluorescent sensing ensemble by combining hairpin-structured DNA segment with pyrene for the detection biological of thiol-containing amino acids and peptides.Bis-pyrene labeled oligonucleotide is designed to switch conformation as the thiol complexes with Hg ion from thymine-Hg2+-thymine by competition.Particularly owing to the switch and the protection of y-CD excimer signal enhances observably.It also has a great performance in serum without background interference.(2)Fabrication of novel two-photon fluorescent probe based on cyclodextrin-functionalized AuNPs to detect H2O2.We report a two-photon fluorescent nanoprobe containing ferrocene and modify thiolated cyclodextrin on the surface of gold nanoparticles.Ferrocene-two photon molecules can enter the cavity of cyclodextrin,forming complexes.Because of closer distance between dye and AuNPs,the fluorescence is quenched.When ferrocene is oxidized by H2O2 and catalysed by HRP,the ferrocene-two photon molecules could get out of the cavity of cyclodextrin,which could get the fluorescence recovery.