Preparation,Assembly And Analytical Application Of Functional Fluorescent Nanoprobes

Owing to the particularity of small size and unique structure,functional fluorescence nanoprobes exhibits distinct physical and chemical properties.It has broad application prospects in sensing,biomarker,bioimaging,medical diagnosis and treatment.Among them,the most important thing is to design and synthesis functional fluorescence nanomaterials with excellent synthetic properties,such as low biotoxicity,strong photoluminescence,good biocompatibility,excellent light stability and so on.In this paper,gold nanoclusters,carbon dots and their composite nanomaterials with excellent performance were prepared through a facile one step method,and based on the quenching of fluorescence intensity,several sensing platforms for the detection of Vitamin B12,cyanide and mercury ions were constructed.Chapter 1: We summarized the research progress on properties,synthesis and applications of fluorescent nanoprobes?metal nanoclusters and carbon dots?.And we described the related research content on this thesis.Chapter 2:We used one-step hydrothermal method for synthesizing fluorescence canbon dots by using saffron as carbon source,and the quantum yield of CDs was 1.95%.The result indicated that vitamin B12 had a quenching effect on CDs,and its degree of quenching showed a good linear relationship with the concentration of vitamin B12 in the range of from 0 to 90 ?M.The detection limit was 312 nmol/L.The method was applied to the detection of vitamin B12 in actual samples?vitamin B12 injection and vitamin B12 eye drops?,and satisfactory results were obtained.Chapter 3: Fluorescence gold nanoclusters?HSA@Ag NCs?were prepared using human serum albumin?HSA?as the template,and had constructed a dual-emissive nanohybrid probe by hybridizing HSA@Au NCs of red fluorescence and CDs of blue fluorescence.The strong fluorescence of HSA@Au NCs was quenched upon the addition of cyanide,thus we have developed a fast,sensitive and selective method for detecting cyanide.Furthermore,a portable paper sensor manufactured by combining the nanohybrid probe for on-site monitor of trace cyanide.This nanoprobe had also been successfully used in the detection of cyanide in actual water samples such as Fenhe River and tap water bymeasuring the recovery rate.Chapter 4: We used vitamin B₉ to conjugate luminescence HSA@Au NCs to assemble a novel dual-emissive fluorescence nanomaterial.As the concentration of Hg2+increases,the fluorescence intensity of the dual-emitting nanoprobe at 642 nm gradually quenches,while the fluorescence intensity remains almost unchanged at 484 nm,the degree of quenching at 642 nm showed a good linear relationship with the concentration of Hg2+ in the range of from 0 to 40 ?M,the detection limit was 105 nmol/L,and a significant color change in the probe solution from pink to blue was observed under UV light.Therefore,this simple and intuitive detection method enables qualitative and quantitative detection of Hg2+.Chapter 5: We summarized the research results on gold nanoclusters,carbon dots and their complexes as a fluorescence probe for applications,and future research was speculated.