Fluorescence Analysis Technology Based On Graphene And Organic Framework Materials

Organic framework materials such as covalent organic framework materials?COFs?and metal organic framework materials?MOFs?can present some advantages of low toxicity,large specific surface area,high stability and adjustable pore sizes,showing a wide range of applications in the fields of catalysis,adsorption,separation,sensing analysis,and drug controlled release.Moreover,noble metal nanomaterials such as gold nanoclusters?AuNCs?,silver nanoclusters?AgNCs?and gold-silver nanoclusters?Au-AgNCs?have also become the hot functional materials in many research fields due to their super-small sizes,excellent luminescence,and high biocompatibility.In this thesis,three kinds of high-performance fluorescence sensing platforms have been established using different COFs,MOFs and gold-silver nanospheres for the highly efficient analysis of copper ions in blood,trace water in organic solvents,and cysteine in cells.The research content mainly includes the follows:?1?A fluorimentric method has been developed with nanocomposites of Q-graphene?QG?and COFs for the detection of Cu²⁺ions in blood and wastewater?Chapter 2?.QG-loaded metal-free fluorescent COFs probes were synthesized by one-step covalent condensation reaction of melamine?MA?-paraformaldehyde?PA?-phenol with QG as the backbone.It was found that QG could enhance the fluorescence,water solubility and environmental stability of COFs.The synthesized QG-scaffolded COFs with rich-NH-CH₂-NH-groups can have strong adsorption to Cu²⁺ions so as to cause the specific fluorescence quenching.The developed fluorimetric method can allow for the rapid,specific and sensitive analysis of copper ions in blood and wastewater?the detection limits of 0.50 nM and 2.4 nM in blood and wastewater,respectively?.?2?A "turn-on" solid-state fluorescent strip has been fabricated using QG-scaffolded MOFs porous composites for the determination of trace water in organic solvents?e.g.ethanol,DMF and aviation gasoline??Chapter 3?.QG-scaffolded MOFs were synthesized as the fluorescent probes by using QG carrier,MA,zinc ions,and 2-aminoterephthalic acid?BDC-NH₂?.The results indicate that QG carrier can effectively enhance the environmental stability of MOFs.Meanwhile,amine-derived MA can enhance the fluorescence intensity of BDC-NH₂ fluorophore by means of the electron donor effect of amine.In addition,the MA resin in the nanocomposites with high viscosity can enhance the load firmness of MOFs probes on test strips.The developed "turn-on" fluorescent strips can detect trace water in organic solvents sensitively and rapidly?the detection limit of water in ethanol of 0.015%?.?3?Fluorimetric test strips were fabricated using protein-coated gold-silver?Au-Ag?nanosphere and ZIF-8 for the detection of cysteine in Hela cells?Chapter 4?.Au-Ag nanoclusters were prepared by the biomimetic mineralization using protein as the template,followed by the desolvation to yield the protein-encapsulated Au-Ag nanospheres.Furhteremore,the resulting nanospheres were coated onto the test strips,which were placed on the surface of superhydrophobic glass panels to be dried rapidly in vacuum.Moreover,ZIF-8 layer was then coated onto the fluorescent test strips for selectively probing Cys.A detection limit of 2.0 nM was obtained for Cys in Hela cells,promising a detection candidate for the early detection and diagnosis of some clinical diseases like cancers.