Application Of Fluorescent Gold Nanoclusters On The Determination Of Metal Ions And Cell Imaging

Chapter 1:The development of nanomaterials is depicted in brief.The preparation methods,characteristic and reaserch and analytical application of gold nanoparticles are reviewed in detail.At last,our reaserch content is put forward.Chapter 2:N-acetyl-L-cysteine?NAC?was used as a green reducing and stabilizing agent to prepare aqueous Au?0?@Au?I?-NAC NCs with mole ratio from Au/NAC at 1:1.5,the high quantum yield?14%?and orange fluorescent at 590 nm.Au?0?@Au?I?-NAC NCs were characterized by means of UV-visible absorption,transmission electron microscope,photoluminescence spectroscopy,thermogravimetric analysis,FTIR,XPS and mass spectroscopy,and numbers of gold atom and ligand were calculated,respectively,namely the average molecular formula of Au?O?@Au?I?-NAC NCs is about Au27NAC32.Based on Au?O?@Au?I?-NAC NCs fluorescence quenching response in the presence of Hg²⁺,a high sensitivity and high selectivity method for the determination of mercury ion was developed.The detection limit was 0.2 nM,and linear range was 2.0-3200 nM.The developed method has been employed to the quantitative determination of mercury ion in tap water,lake water and sewage.It provides contain acdamic basis for water quality determination.In addition,Au?O?@Au?I?-NAC NCs has good biocompatibility,high brightness and flicker free characteristic,so that they can be used as fluorescent probes for better detection of single molecules and biological imaging.By combining confocal laser scanning microscopy,it acquired the novel fluorescence imaging in living BIU-87 bladder cancer cells.Chapter 3:The uniformly dispersed MBISA@Au NCs were synthesized by thiol-ligand 2-Mercapto-5-benzimidazolesulfonic acid sodium salt?MBISA?as a reducing and modifier agent.The particle size,morphology and structure of MBISA@Au NCs were studied by transmission electron microscopy?TEM?,themogravimetric analysis?TGA?and mass spectroscopy?MS?.The TEM images show that the MBISA@Au NCs had a spherical shape with diameters of about 1.5±0.1 nm.The UV-vis absorption spectrum of MBISA@Au NCs displays that the absence of the typical surface plasmon resonance band at 520 nm indicates that as-synthesized NCs product have dimensions<2 nm.IR spectrometry identify the form of Au-S bond.The TGA data also determined the MBISA fractions on the nanoclusters to be 50 wt%of the nanoclusters.Combining the MALDI-TOF MS spectrum,we can estimate that MBISA@Au NCs are cracked into AuNCs fragments with five gold atoms and five ligands in the characterization process.The photoluminescence properties of MBISA@Au NCs have been investigated.The results show that strong emission peak of the NCs appeared at 630 nm and exhibited a large Stokes shift?270 nm?.The effect of different kinds of ions on fluorescence intensity of MBISA@Au NCs was investigated.Of all the ions tested,only the addition of Hg²⁺ gave a significant quenching response in the fluorescence intensity of the MBISA@Au NCs aqueous solution and the response toward Hg²⁺ was highly linear over the concentration range from 4.0×10-9 M-2.0×10-5 M,here LOD was found to be 0.5 nM.Besides,the novel fluorescence imaging is acquired in living BIU-87 bladder cancer cells.Chapter 4:The interaction of 2-Mercapto-4-methyl-5-thiazoleacetic acid?MMTA?functionalized MMTA-AuNCs with iron ions is studied by fluorescence spectroscopy.Different experimental parameters were explored including the dosage of MMTA-Au NCs,solution acidity,and reaction temperature and time in a univariate approach.Under the best of circumstances,there were good linear dependence of fluorescence intensity on Fe³⁺ concentration over the concentration ranging from 9.9 to 3000.0 nM and 3.0 to 1100?M and the limit of detection?LOD?for Fe³⁺ ions was 3.0 nM.The proposed method exhibits high sensitivity,good repeatability,long-term stability and has been employed to the quantitative determination of iron ion in practical sample.