The Preparation And Analytical Application Of Novel Platinum Nanoclusters

In recent years,metal nanoclusters have become a research hotspot in the fields of biology,materials,physics,chemistry and medicine,due to their unique optical properties and ultra-small nanometer size.As a newly emerging material,they have been widely applied in biosensing,bioimaging,biocatalysis and environmental monitoring fields.Among them,platinum nanoclusters(Pt NCs)ha ve been gotten great attentions of scientists because of their high catalytic activity and good biocompatibility.However,compared with gold and silver nanoclusters,the studies about preparation and application of platinum nanoclusters are still rare.Therefore,it is of great significance for the rapid development of nanotechnology and life analysis to develope new methods and technologies of preparing platinum nanoclusters,and explore their potential applications in biosensing.In this thesis,we prepared Pt NCs materials with yeast extract as template.With the help of Pt NCs peroxidase mimic enzyme catalytic activity and fluorescence characteristics of p H response,a glucose colorimetric sensor based on Pt NCs that can detect glucose in human serum and a p H nanosensor based on Pt NCs fluorescence lifetime to detect p H change in simulated physiological environment solution were successfully constructed.This thesis mainly includes two aspects of work:The first part of this work: The content of glucose in human serum was determined by colorimetry using the peroxide mimic enzyme properties of platinum nanoclusters.A new type of ultrasmall platinum nanoclusters material has been prepared by a simple,green,one-pot method by using yeast extract as the stabilizer and reductant.The experimental results showed that the prepared Pt NCs have excelle nt water solubility and stability.At the same time,we found that yeast extract-stabilized Pt NCs also possess attractive peroxidase mimics property.They c an effectively catalyze the color reaction of TMB-H2O2 system.Through the investigation of the catalytic mechanism,we speculated that the peroxidase mimics catalytic activity of Pt NCs may be due to its characteristics of accelerating the electron transfer between TMB and H2O2.The analysis of catalytic mechanism suggested that the enzymatic kinetics of Pt NCs follow typical Michaelis-Menten theory,these Pt NCs can accelerate the electron transfer between TMB and H2O2.Based on these research,we have developed a new colorimetric method for glucose detection based on Pt NCs.The linear detection range of glucose was 0-200 ?M,and the limit of detection was 0.28 ?M(S/N=3),which is comparable with other colorimetric methods of detecting glucose reported in previous literature,and it can be successfully used for the determination of glucose in human ser um.As an efficient mimic peroxidase,Pt NCs has a broad application prospect in the field of disease diagnosis,pharmaceutical and environmental chemistry.The second part of the work: High-sensitivity monitoring the p H changes in environment based on fluorescence lifetime changes of platinum nanoclustersIn this work,we developed a new method based on Pt NCs fluorescence lifetime to detect p H change in solution for the first time.Compared with the fluorescence method,the application of fluorescence lifetime can effectively avoid the influence of external interference factors such as solution environment and probe concentration in the detection results.The experimental results show that the fluorescence lifetime sensor based on Pt NCs has a higher sensitivity in the range of physiological p H.The fluorescence lifetime of the Pt NCs nanosensors showed a linear response over the physiological p H range of 6.02-7.54.The linear regression equation is ?=-4.9584 p H+48.728,R2=0.997.On this basis,we also successfully used this method to monitor the p H changes of simulated cell medium solution.