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Research On The Detection And Sensing Mechanism Of Silver Ion Based On Au@Pt Nanozyme

Posted on:2021-12-06Degree:MasterType:Thesis
Country:ChinaCandidate:Y Y TianFull Text:PDF
GTID:2481306122464264Subject:Analytical Chemistry
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As the artificial nanomaterial with enzyme activity,nanozymes have attracted wide interest from scientific researchers.Compared with natural enzymes,nanozymes are easy to modify and have higher catalytic stability and lower manufacturing costs.Nanozymes are not only excellent natural enzyme substitutes,but also have unique physicochemical properties of nanomaterials,which can build the multifunctional platforms for applications such as catalysis,sensing and drug delivery.Therefore,nanozymes have been widely used in biosensors,biology and medicine.Among them,Au@Pt nanozymes have catalytic activities similar to peroxidase a nd superoxide dismutase,which have attracted more and more attention from researchers,and have been successfully used in the development of sensor technology and the preparation of antioxidant and other applications.Based on this,this paper develops a new method for silver ion detection by synthesizing Au@Pt nanozymes with peroxidase catalytic activity.At the same time,using dark field imaging technology,the mechanism of silver ion sensing based on nanoenzymes was investigated at the single particle level.In chapter 2,the rod-shaped Au@Pt nanozymes with peroxidase activity was synthesized and used the as integrated nanoprobes for selective detection of silver ions.This method relies on two critical chemical reactions,including(1)the selective inhibition of Au@Pt nanozyme catalyzed H2O2 decomposition by Ag+at weak acid environment and(2)H2O2 induced Ag+reduction onto the surface of Au@Pt nanozyme at basic environment,leading to the blue-shift in the LSPRlmax of Au@Pt nanozyme.According to the relationship between the Ag+concentration and the spectral offset,the purpose of Ag+detection is achieved.In addition,based on the dark field imaging technology,the sensitivity of the detection principle can be further improved.With this satisfying sensing performance and excellent stability of nanoprobes,this strategy is promising for the detection of Ag+in environment monitoring and food safety analysis.In chapter 3,the spherical Au@Pt nanozyme with peroxidase activity was synthesized by ion sputtering and its movement behavior in H2O2 solution was studied based on dark field imaging technology.Compared with the 40%glycerol solution,the movement speed of Au@Pt nanozyme increases in H2O2 solution and has a positive correlation with the concentration of H2O2.At the same time,the curve of MSD of Au@Pt nanozyme with time has a tendency to bend upward,indicating that in H 2O2solution,Au@Pt nanozyme starts to do directional m otion.In addition,Au@Pt nanozyme can continuously switch between Brownian motion and directional motion.With the increase of H2O2 concentration,the time for Au@Pt nanozyme to do Brownian motion decreases,while the time to do directional motion increases,indicating that the higher the fuel concentration,the greater the driving force.In addition,Ag+can inhibit the movement behavior of Au@Pt nanozyme in H2O2 solution.In the presence of Ag+,the movement speed of Au@Pt nanozymes slows down,which makes Au@Pt nanozymes have potential applications in Ag+ sensing.
Keywords/Search Tags:Nanomaterials, Au@Pt nanozyme, Silver ion detection, Catalytic activity, Directional motion
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