Green Synthesis And Application Of Fluorescent Copper Nanoclusters

In recent years,metal nanoclusters(MNCs)have been widely used in environmental detection,cell imaging,cancer diagnosis and treatment due to their excellent luminescent properties,controllable emission wavelength,large Stokes shift,good biocompatibility and high photostability.Compared with gold,silver,platinum and other metal nanoclusters,copper nanoclusters(Cu NCs)are widely considered as the most cost-effective nanomaterials because of their low cost,non-toxic and good biocompatibility.In this paper,fluorescent Cu NCs were synthesized using plants and small molecules as templates.Their properties were characterized by UV-Visable spectroscopy,fluorescence spectroscopy,XPS and TEM.Based on the fluorescence quenching mechanism,the sensing system for Doxorubicin hydrochloride and picric acid were constructed.Chapter 1: The synthesis,properties and applications of MNCs in different fields are introduced,and the experimental design idea of this paper is briefly described.Chapter 2: In alkaline environment,blue fluorescent copper nanoclusters were green synthesized using green tea extract as template(Tea@Cu NCs).The average particle size of the Tea@Cu NCs is 2.08 nm,and the optimal excitation and emission wavelengths are 389 nm and 472 nm,respectively.Meanwhile,it was found that the Tea@Cu NCs could be sensitively detected to Dox at room temperature,and when the Dox concentration was increased from 0 to 150 ?mol/L,the emission intensity of the Tea@Cu NCs gradually decreased and a weak blue shift appeared.The same emission point and new emission peak appear at 604 nm and 640 nm,respectively.A linear analysis of the fluorescence intensity changes due to Dox concentration was performed,which showed that a good linear relationship between the fluorescence intensity ratio and different concentrations of Dox appeared in the range of Dox concentrations from 5 to 105 ?mol/L,with a detection limit of 0.08 ?mol/L.The detection of Dox in real urine was also achieved.Chapter 3: Using the small molecule arginine(Arg)as the template,high-fluorescence copper nanoclusters(Arg@Cu NCs)were synthesized in one step in a short time.The excitation and emission wavelengths were 382 nm and 479 nm,respectively,and the quantum yield was 1.22 %.The sensitive detection of PA was achieved under room temperature conditions.Based on the static quenching,the fluorescence intensity of the Arg@Cu NCs decreased significantly with increasing PA concentration,and the emission peaks were weakly red-shifted.In the concentration range of 45-190 ?mol/L of PA,a significant linear relationship with the fluorescence intensity ratio appeared,and the detection limit was 0.065 ?mol/L.And the method was successfully applied to the detection of PA in actual water samples,which can be applied to environmental and biological fields.Chapter 4: A summary of the characteristics of Cu NCs and their applications as fluorescent sensors in this paper is presented,and an outlook on the follow-up work is given.