Surface-enhanced Raman Spectroscopy Based On Gold-Shell Nanoparticles And Its Application In Detection Of Environmental Pollutants

With the improvement of people's living standards,the demand for better quality of living standard and better control of environmental pollution is more and more emphasized.The pollution caused by human activities may not only destroy the ecological environment,but also bring harm to the human health and safety.Therefore,it is of imminent importance for researchers to develop quick,sensitive and effective methods for detection of environmental pollutants.Surface Enhanced Raman Spectroscopy(SERS),as a rapidly developing technology,has attracted wide attention due to its characteristics of rapidness,non-destructiveness and high sensitivity in measurements.After decades of research and development,people have made a lot of progress on the theories and applications in SERS technology.Gold shell nanoparticles can be used for SERS application because of its good enhancement effect,biocompatibility,and plasmon resonance with infrared laser.Here,we mainly focus on two representative environmental pollutants:persistent organic pollutants(POPs)and heavy metal ions.By preparing gold coated silica shell nanoparticles with different homogeneous sizes,trace polychlorinated biphenyls and mercury ions in solution were detected with SERS.Therefore,the main findings of this thesis work are summarized as follows:(1)Size-controllable gold-coated silica nanoparticles(denoted as SiO2@Au)based on seed growth method were synthesized,and the well-dispersed gold shell nanoparticles with different sizes of 140-310 nm with good SERS activity have been achieved.(2)Using SiO2@Au nanoparticles,trace detection of one persistent organic pollutant polychlorinated biphenyl(PCB-77)has been achieved,with the detection limit as low as 10"7 M;(3)Using SiO2@Au nanoparticles,the DNA aptamer specific for mercury ions was modified on the surface of the nanoparticles which could capture Hg2+,and with this system the detection of Hg2+ in water has been achieved.The response range is 10-5M?10-8M and the limit of detection is 10-8M.