The Preparation Of Metal Nanoparticles And Their Properties Of Detection Formercury Ions

Metal nanoparticles, which have unique electronic structures and superb physical and chemical properties, are universally applied in the fields, such as biological detection, biochemical sensing, optical imaging and so forth. Nowadays, outstanding professors and eminent scholars have paid more and more attention to the resonant characteristics of plasma on metal nanoparticles, which are served as colorimetric probe and fluorescence probe in order to detect the water environment and heavy metal ion in the biologic cells. However, a great deal of efforts should be made to the metal nanoparticles detection of heavy metal ions. Therefore, synthetising detection probes of metal nanoparticles, which have the properties of short response time, a high degree of sensitivity, good biocompatibility and low toxicity, will be the further research area.Gold, silver, copper nanoclusters with fluorescent properties were synthesized, which were serves as detection probe for the sake of detecting the heavy metal ions, what is more, they were also applied for the study of cell imaging. The functionalized gold nanoparticles were utilized for detection probe in order to detect the heavy metal ions. The detailed experiments are as follows:(1) The thioctic acid functionalized gold nanoparticles(TA-GNPs) combined with UV-vis served as sensors for the colorimetric detection of Hg2+ ion in water samples. After adding into Hg2+, TA-GNPs could aggregate quickly and lead to the change of solution color, consequently, achieve the purpose of detecting Hg2+ in aqueous solution. Thorough the comprehensive analysis of sensors’ sensitivity and selectivity, the experiments effectively proved the high sensitivity and high selectivity of this methodology, meanwhile, the probe could be used for detecting Hg2+ with the minimum detectable concentration at 10 nM.(2) Folic acid functionalized silver nanoparticles(FA-AgNPs) with both colorimetric and fluorescent functions were employed as detection probe for the detection of mercury ion. The presence of Hg2+ in the solution could make FA-AgNPs aggregate quickly and lead to the change of solution color, furthermore, FA-AgNPs emitted stable ?uorescence at 440 nm when the excitation wavelength was 275 nm. The sensors exhibit two linear response ranges between absorbance and ?uorescence intensity with different Hg2+ concentrations respectively. Simultaneously, a detection limit of 1 nM is tested based on the linear relationship between responses with different concentrations of Hg2+. The results of simulated applied experiments showed that the detecting probe FA-Ag NPs had good environmental adaptability and the proposed method could be applied for the accurate analysis of Hg2+.(3) The research aimed to synthesize folic acid functionalized gold nanoclusters(FA-Au-NCs) which was used as the sensor for detecting Hg2+ in water environment and biologic cells. The emission band spectrum of FA-Au-NCs showed an emission maximum at 440 nm while being motivated at 275 nm. Under UV light(365 nm), the FA-Au-NCs solution emitted intense blue fluorescence. The fluorescence lifetime of FA-Au-NCs was 6.11 ns and the fluorescence quantum yield was measured as 21%. In this detection, a highly sensitive and selective fluorescence sensor for Hg2+ was developed according to the fluorescence quenching of FA-Au-NCs. Combined with fluorescence spectrum test, this probe could be used for detecting Hg2+ with the minimum detectable concentration at 1 nM. On account of detecting Hg2+ in the natural water samples and Hela cells, the experimental results showed that FA-Au-NCs fluorescence detection probe had a good practicability.(4) Folic acid functionalized Cu nanoclusters(FA-Cu-NCs) could be applied as a fluorescence probe for the detection of Hg2+ in the natural water and biologic cells. FA-Cu-NCs could emit blue ?uorescence at 440 nm when the excitation wavelength was at 275 nm. The FA-Cu-NCs synthesized could make an accurate and expeditious detection to Hg2+. The fine environment adaptability could be effectively attested through the thorough research of the practical application of FA-Cu-NCs.