Research And Application Of Nano Fluorescence Probe

Owing to the particularity of size and structure,nano fluorescence probe exhibits distinct physical and chemical properties with the macro material,such as small size effect,quantum effect,surface effect and quantum tunnel effect and so on,and has a broad application prospect in the medicine,science and technology,energy,military and other fields.In recent years,applications of nano fluorescence probe in chemical sensing and biomedical fields have been a research hot spot,of which the most important thing is to design and synthesis nano-materials with the excellent properties,such as uniform particle size,stable optical properties,good water solubility and biocompatibility.In this paper silver nanoclusters,carbon dots and their nanohybrids with excellent performance were prepared through a facile one step method,and new sensing platforms based on the above nano-materials were build for the detection of S^2-,Fe³⁺,Al³⁺ and cancer cell.Chapter 1:We reviewed the research progress on synthesis and application of Ag NCs,CDs and their nanohybrids.Chapter 2: At room temperature,lysozyme-stabilized silver nanoclusters?Lys-Ag NCs?were synthesized through a simple approach where lysozyme and NaBH₄ were used as a template and a reductant,respectively.Based on the strong and specific interactions between S^2-and Ag/Ag⁺,S^2-could quench dramatically the fluorescence of Lys-Ag NCs,thus we developed a method to sensitively and selectively detect S^2-.The method owned a good response to S^2-in the linear range of 5.0 × 10-6 M-1.0 × 10-4 M and the corresponding detection limit was 1.1 × 10-6 M?S/N=3?.Satisfactory recoveries in the range of 97-101.4 % demonstrated that the proposed method is feasible and can be applied to the detection of S^2-in environmental samples.Meanwhile,the possible sensing mechanism for the detection of S^2-was also discussed.Chapter 3:Blue-emitting fluorescent CDs were prepared by a facile hydrothermal method where proline and ethylenediamine were used as carbon source and nitrogen source,respectively.Active amino groups on the surface of CDs coud conjugate with FA through the classical EDC/NHS reaction and generate CDs-FA compound.Based on the high affinity between FA and folate receptor?FR?and FR mediated endocytosis,CDs-FAcompound could target and detect FR-positive cancer cell,and then distinguish FR-positive cancer cells from FR-negative normal cells,which makes it of great potential for cancer diagnosis and therapeutic studies.Chapter 4 : We synthesized the blue fluorescent CDs by one step hydrothermal method using cyclodextrin as carbon source.Abundant oxygen-containing functional groups such as hydroxyl and epoxy groups on the surface of CDs make CDs not only has the characteristics of the reducing agent,but also can act as a protective agent in the process of the synthesis of nanoclusters.Green-emitting CDs-Ag NCs nanohybrids were prepared from CDs and Ag⁺ through a facile hydrothermal method.In the presence of Fe³⁺,the fluorescence of CDs-Ag NCs nanohybrids could be quenched efficiently,while the fluorescence of the system could be enhanced in the presence of Al³⁺,thus we developed“turn-off”sensing system for Fe³⁺ and “turn-on”sensing system for Al³⁺.The corresponding linear ranges for Fe³⁺and Al³⁺were 5.0 × 10-6M-3.6 × 10-4M and 2.0 ×10-5 M-1.8 × 10-4 M,respectively.The detection limits?when S/N=3?were 2.6 × 10-6 M for Fe³⁺ and 4.8 × 10-7 M for Al³⁺.The satisfactory recoveries in both sensing system indicated that the CDs-Ag NCs probe has great potential for the detection of Fe³⁺and Al³⁺.Chapter 5:We summarized the research results about the Ag NCs,CDs and their compound as fluorescence probe/ marker for applications in ion sensing and targeting cancer cell imaging,and the future work was speculated.