Construction Of Time-resolved Rare Earth Luminescence Probe Based On Energy Transfer And Its Application In Fluorescence Detection

Rare earth elements have unique optical properties,such as long emission lifetime and narrow emission band,and are widely used in the field of luminescent materials,fluorescence detection and catalysis.In addition,DNA has functions such as programmability,molecular recognition and catalysis,and is an important biological molecule.In this thesis,by combining the respective advantages of rare earth elements and DNA,the luminescence regulation of DNA sensitized rare earth ions,the construction of fluorescent probes based on DNA sensitized rare earth and their research in time-resolved fluorescence detection were carried out.（1）Construction of Eu（Ⅲ）fluorescent probe based on guanine-rich DNA sensitization and its fluorescence detection applicationsThe luminescence effect of Tb³⁺sensitized by different DNA sequences was studied in detail.Among them,guanine-rich DNA（5’-22Ag-3’）showed significant sensitizing ability to Tb³⁺luminescence,and the binding mode of 22Ag sensitized Tb³⁺was studied at the same time.In addition,the Tb³⁺/22Ag probe was designed for the time-resolved fluorescence detection of Hg²⁺.This is due to the specific binding of Hg²⁺to the T pyrimidine in the 22Ag chain,which makes the probe Tb³⁺/22Ag fluorescence quenched to achieve the rapid Hg²⁺detection.Furthermore,based on the high affinity of biothiols for Hg²⁺,the Tb³⁺/22Ag-Hg²⁺composite fluorescent probe was used for the fluorescence detection of biothiols of Cys,GSH and Hcy.Finally,we used the Tb³⁺/22Ag probe for time-resolved fluorescence detection of the anti-tumor drug daunorubicin.Compared with traditional detection methods,this detection system has the advantages of simple operation,short response time,no labeling and low cost.（2）Construction of Eu（Ⅲ）fluorescent probe based on cytosine-rich DNA sensitization and its fluorescence detection applicationsWe selected the sequence 5’-CCCTAACCCTAACCCTAACCCT-3’（named 22CT）complementary to 22Ag to construct the fluorescent probe of Eu³⁺/22CT.The sensitization ability of 22CT to Eu³⁺was studied in detail,and it was found that 22CT has a good antenna sensitization effect to Eu³⁺.In addition,the study found that based on the 22CT base sequence,increasing the T base content can enhance the sensitization effect of Eu³⁺luminescence.Furthermore,our studies have shown that the Eu³⁺/22CT fluorescent probe can respond to Hg²⁺and has a good response range.Finally,the use of Eu³⁺/22CT luminescent probe to track the dynamic changes of 22Ag and22CT complementary hybridization process in real time has been extended,which can provide a highly sensitive and real-time tracing method for DNA hybridization process.（3）Energy transfer based rare earth upconversion luminescence composite system for detection of peroxynitrite The core-shell double-layer rare earth nanoparticles are prepared by thermal decomposition method.The silica-coated yolk-shell structure rare earth nanoparticles YSUCNP were prepared by the soft template method of surfactant.The outer layer of mesoporous silicon endowed the hydrophilicity of the rare earth nanoparticles YSUCNP.Furthermore,the structure of rare earth nanoparticles YSUCNP was functionalized with fluorescent probe NOF2 to obtain a composite detection system YSUCNP-NOF2 with ability of peroxynitrite detection.The composite system YSUCNP-NOF2 can realize upconversion luminescence detection of peroxynitrite based on energy transfer in pure water system.Taking advantage of the near-infrared excitation of rare earth upconversion nanoparticles,upconversion luminescence detection of peroxynitrite with low background and high specificity can be achieved.