Synthesis Of Gold Nanoclusters And Its Application In Analytical Chemistry

Gold nanoclusters(Au NCs)are comparable in size to the Fermi wavelength of electrons and can produce similar molecular properties such as discrete electronic states and size-dependent fluorescence.Au NCs are widely used in fluorescence sensing,biological imaging,drug transportation,and catalysis because of their advantages such as simple preparation,light stability,good biocompatibility,and low toxicity.However,few studies have used Au NCs to detect enzyme activity and interact with proteins.Human serum albumin(HSA),as the most abundant protein in human plasma,is an important part of human plasma,accounting for about 60% of the total plasma.It plays a vital role in transporting hormones,drugs,fatty acids,heme and inorganic salt ions.Therefore,study of the interaction between gold nanoclusters and HSA is of great significance for evaluating the toxicity of Au NCs at the protein level and its application in the biological field.As one of the important biomarkers in clinical research,the content of alkaline phosphatase in serum is related to many diseases such as diabetes,breast cancer and abnormal liver function.Therefore,a method that can quickly and sensitively detect the alkaline phosphatase has a profound impact on clinical research.Pyrophosphate(PPi)plays a vital role in life processes such as cell metabolism and certain enzymatic reactions.In addition,PPi also has a significant role in the pathological process of arthritis,and can be used as a potential biomarker for the clinical diagnosis and treatment of arthritis diseases.Therefore,it is urgent to develop a new method for sensitive and efficient detection of PPi.This thesis conducts the following research on Au NCs:Chapter 1: Summarized the research of Au NCs in recent years,the preparation methods and their applications in the detection of enzyme activity and small molecules.Chapter 2: The orange-emitting Au NCs using DNA as a template were synthesized.Investigated the interaction between Au NCs and HSA by spectroscopic methods,and the toxicity of Au NCs at the molecular level was explained.The results showed that Au NCs mainly bind to site I of HSA,and the forces between them were mainly van der Waals forces and hydrogen bonds.In addition,Au NCs can slightly change the secondary structure of HSA.Chapter 3: The fluorescent Au NCs(GSH-Au NCs)with photobleaching resistance and salt tolerance using glutathione as a template were synthesized.Based on the internal filtering effect,a sensitive and selective method of alkaline phosphatase was achieved.Under the best experimental conditions,the linear range of this method was 0.01-7.0 U / L,and the detection limit was 0.003 U / L.In addition,it was also used for the detection of alkaline phosphatase in human serum,and the test results were compared with commercial kits,and the results are the same basically.Chapter 4: After added Al3+ to the GSH-Au NCs,the nanoclusters aggregated and cause their fluorescence increasing.After added PPi to this Al3+-Au NCs system,due to the strong coordination between Al3+ and PPi,the Au NCs were re-dispersed,which in turn caused the fluorescence of the Al3+-Au NCs system quenched,which enables the selective detection of PPi.The method has a linear range of 0.3-100 m M and detection limit of 0.1 m M.In addition,this method was used to detect PPi in human urine.Chapter 5: Conclusion and Outlook...