Preparation Of Fluorescent Nanomaterials And Their Applications In Sensing And Cell Imaging

In this paper,metal nanoclusters and carbon dots were used as fluorescent probes to construct biosensor,combined with fluorescence spectroscopy and chemometrics,some substances(riboflavin,tartrazine and Cu²⁺)in actual samples were quantitatively analyzed by sensing and cell imaging techniques.The nanomaterials mentioned in this paper are environmentally friendly,simple and fast to synthesize,and have high sensitivity and selectivity for detection.The main contents of this paper are as follows:Chapter 1:Introduce nanomaterials,and systematically elaborate the research background,physical and chemical properties,common preparation methods and application in analysis and detection of metal nanoclusters and carbon dots;simply describe the research background and current situation of several detection objects;puts forward the innovative points of this paper;and look forward to the application prospect of nanomaterials in other fields.Chapter 2:Fluorescent gold nanoclusters were synthesized using adenosine,ascorbic acid,citrate buffer solution and chloroauric acid as raw materials through the strategy of"synthesis-functionalization".The morphology,structure and chemical properties of the synthesized gold nanoclusters were characterized by ultraviolet-visible absorption spectroscopy,transmission electron microscopy,X-ray photoelectron spectroscopy,Fourier transform infrared spectroscopy and fluorescence spectroscopy.Due to photoinduced electron transfer（PET）between gold nanoclusters and riboflavin,the fluorescence of gold nanoclusters was quenched.Using the fluorescence of gold nanoclusters and the fluorescence of riboflavin itself,combined with fluorescence spectroscopy and chemometrics,a fluorescence quenching and ratio sensor was constructed,and finally applied to the analysis and detection of riboflavin in real samples.Chapter 3:Water-soluble fluorescent nickel nanoclusters were synthesized by one-pot method using bovine serum albumin as template and reductant.In addition,we use hydrogen peroxide as an additive to improve the fluorescence quantum yield of nickel nanoclusters.The morphology,structure and chemical properties of nickel nanoclusters were analyzed by various characterization methods.Then,the synthesized nickel nanoclusters were used as fluorescent probes to construct a sensors for the sensitive and selective detection of food colorant tartrazine.Chapter 4:Adenine-stabilized carbon dots with high fluorescence quantum yield were prepared by one-step hydrothermal method using sodium citrate and adenine as starting materials.It was found that the addition of copper ions would cause the fluorescence quenching of carbon dots,and a copper ion fluorescence sensor was constructed accordingly.It was also found that the fluorescence quenching was attributed to the electron transfer process between the surface functionalized carbon dots and copper ion.In addition,the prepared carbon dots have good water solubility,high light stability,good pH stability,fast response time and low cytotoxicity.Accordingly,we studied the copper ion cell imaging of carbon dots.The main innovations of this paper are:（1）synthesizing nanomaterials with high selectivity and sensitivity,and applying them to the quantitative detection of some substances in real samples,all of which have obtained good experimental results;（2）applying chemometrics to fluorescence sensors,fluorescence quenching and ratio sensors have been constructed,and the possible mechanism problems in the detection process have been reasonably explained.