Modification And Application Of Amino Acid Fluorescent Gold Nanocluster Schiff Base

It is an important technology and means of life science research to use fluorescence probe which has the advantages of simple design,rapid response and the advantages of in situ,real-time detection and real-time imaging to monitor substances related to life activities.The traditional organic fluorescent probe has a series of advantages,such as high sensitivity and strong specificity,but it also has the disadvantages of strong toxicity,poor biocompatibility,poor solubility in water,complex preparation,and easy to be disturbed by cell or tissue self-fluorescence interference.In recent years,the preparation of simple inorganic Nano fluorescent probes has attracted wide attention due to their high sensitivity,low toxicity and good biocompatibility.However,at present,most of these probes have low fluorescence intensity or insufficient fluorescence properties.It is difficult to realize the problem of high efficiency application in biological research.Nanoclusters are a new class of nanomaterials.Due to their excellent physical and chemical properties,high water solubility,good biocompatibility,low toxicity,excellent stability and strong photoluminescence,nanoclusters have been used as fluorescent molecular markers in recent years.Biological imaging,biochemical analysis and other fields have become the focus of research.Bioprotective nanoclusters are a class of fluorescent probe candidate materials synthesized or protected by specific biomolecules.Due to the existence of a large number of functional groups on its surface,it is easy to be modified by biochemistry.It is convenient to modify and functionalize the surface biomolecules in order to improve their biocompatibility and further improve their physical and chemical properties,which provides the possibility for the study of new methods and techniques of biological analysis and detection,and has higher research value and significance.Based on the above,several kinds of Amino acid protected fluorescent gold nanoclusters were prepared,and the possibility of functionalizing them by Schiff base reaction was discussed.It was found that Schiff base reaction could modify the lysine-protected gold nanoclusters.Furthermore,Lys-SA @ au nanocluster Lys-SA@Au NCs N was prepared,which showed excellent "double fluorescence" optical properties.Based on this,a "double fluorescence" ratio fluorescence probe detectionmethod with high sensitivity for copper ions was constructed.At the same time,due to its optical properties,the imaging of Lys-SA@Au NCs in tobacco suspension cells was explored.In addition,the possibility of preparing fluorescent carbon nanomaterials based on biological carbon source was explored,and its optical properties were preliminarily analyzed.The main conclusions of this thesis are as follows:1.Lysine gold nanoclusters prepared with lysine as protective agent have excellent physical and chemical properties and optical properties.Secondly,lysine gold nanoclusters can be modified by Schiff base reaction through salicylaldehyde.The modified Lys-SA@Au NCs has two fluorescence emission peaks,430 nm and 535 nm,and the ratio of fluorescence intensity of the two peaks can be regulated by the concentration of salicylaldehyde.2.According to the optical properties of Lys-SA@Au NCs,a ratio fluorescence probe sensor with high sensitivity was constructed.It was found that copper ion only had a quenching response to the fluorescence emission peak at 430 nm,but not to the fluorescence emission peak of 535 nm.Therefore,its detection limit is 1.5 ?M,and the fluorescence intensity ratio has a good linear relationship with the concentration of Cu2+.3.The imaging distribution of Lys-SA@Au NCs in tobacco suspension cells was preliminarily studied.It was found that Lys-SA@Au NCs was able to enter the tobacco suspension cells well and showed its fluorescence characteristics.4.Four carbon spots doped with different elements were prepared by hydrothermal synthesis with lily polysaccharides as the basic carbon source,and their basic fluorescence properties were studied and analyzed.(1)When the excitation wavelength is 370 nm,the emission wavelength of the modified carbon point(NCDlps)has the best fluorescence absorption peak at 490 nm.(2)When the excitation wavelength is 430 nm,the emission wavelength of the modified carbon point(SCDlps)has the best fluorescence absorption peak at 520 nm.(3)When the excitation wavelength is 380 nm,the emission wavelength of the modified carbon point(PCDlps)has the best fluorescence absorption peak at 510 nm.(4)When the excitation wavelength is 370 nm,the emission wavelength of the modified carbonpoint(NSCDlps)has the best fluorescence absorption peak at 460 nm.At the same time,they all show good Stokes displacement characteristics.