Application Of Near-infrared Fluorescence Gold Nanoparticle In Sensing Analysis

The mercapto compound-modified gold nanoparticles can not only improve the water solubility of the gold nanoparticles,but also have a small particle size of about 1-5 nm,thus exhibiting distinctly different photoelectric properties.In this paper,gold nanoparticles based on N-acetyl-L-cysteine as the modifier were synthesized.A series of chemical and biological sensors were constructed based on the near-infrared fluorescence of gold nanoparticles.Chapter 1:The concept of nanomaterials is briefly described,and the properties,preparation methods,characterization methods of gold nanomaterials,and the applications of gold nanoparticles in catalysis,light,and electrochemistry are summarized in detail.Finally,the background,research contents and innovations of this thesis are introduced.Chapter 2:We used NAC as a ligand modifier under ice bath conditions to reduce the chloroauric acid by sodium borohydride to synthesize single-layer modified gold nanoparticles with good water solubility.At the same time,p-aminobenzoic acid was used as the carbon source,and m-phenylenediamine was the nitrogen dopant.Nitrogen-doped carbon dots were synthesized by hydrothermal method.We used carbon dots as energy donors and gold nanoparticles as energy receptors to construct a novel fluorescence resonance energy transfer system and successfully established a novel fluorescence resonance energy transfer system based on the quenching effect of L-Cysteine on the near-infrared fluorescence of gold nanoparticles.A new method for the determination of L-Cysteine by a ratiometric method.Under the optimal experimental conditions,the linear range of the method was 1×10^-66 mol/L-1.2×10^-44 mol/L,the detection limit was 1×10^-77 mol/L,and the correlation coefficient was 0.9989.By studying the effect of L-Cysteine on the fluorescence lifetime of gold nanoparticles,the reaction mechanism was discussed.Chapter 3:We combined the near-infrared fluorescence properties of NAC-AuNPs with the catalytic properties of horseradish peroxidase to develop a new method for the determination of H₂O₂.In the presence of horseradish peroxidase and phenolic compounds,the near-infrared fluorescence of gold nanoparticles was effectively quenched with the addition of hydrogen peroxide,and the degree of quenching reached more than 90%.Studies have shown that horseradish peroxidase and hydrogen peroxide catalyze the oxidation of phenolic compounds to produce the intermediate phenylhydrazone compounds play an important role in the quenching of near-infrared fluorescence.Therefore,combined with the strong quenching and effective enzymatic reaction of quinones on gold nano near-infrared fluorescence,a simple and sensitive method for the indirect determination of H₂O₂ was established and compared with the direct assay.Chapter 4:The gold nanoparticle and glucose oxidase hybrid materials were used as near-infrared fluorescent probes to quantitatively measure glucose based on fluorescence sensitization.Various factors such as pH,concentration of gold nanoparticles and glucose oxidase,reaction time were investigated.Influence and optimize it.The linear range of the method is 5×10^-5 mol/L-6×10^-4 mol/L.The detection limit is 1×10^-66 mol/L.and the correlation coefficient is 0.9906.