Preparation,Optical Properties Of Alloy Nanoclusters And Their Application In Biology

Metal nanoclusters?NCs?have been widely studied in fields such as fluorescence imaging,biological analysis,optoelectronic devices and cancer therapy,due to their unique electronic structure and luminescence properties,good photostability,and good biocompatibility.In recent years,alloy nanoclusters have attracted attention due to their Fluorescence enhancement compared with their single metal nanoclusters.In this thesis,the optical properties of different metal-doped gold and silver nanoclusters and their applications in biology were been studied.The main contents and results are as follows:?1?The structures of AuZn NCs,AgAu NCs,AgZn NCs,and AgCu NCs formed by the chemical doping method were studied.Transmission electron microscopy and dynamic light scattering results showed that the particle size of AuZn NCs was about1.84 nm.Physical measures such as Fourier infrared spectroscopy and XPS spectroscopy showed that Zn was successfully doped into Au NCs,and Au,Zn,Cu were successfully doped into Ag NCs to form bimetallic nanoclusters AuZn NCs and AgAu NCs,AgZn NCs,AgCu NCs.?2?Glutathione-protected Zn-doped Au NCs and dihydrolipoic acid-protected Au-,Zn-,and Cu-doped water-soluble Ag NCs were successfully prepared by a chemical reduction method.Then UV-vis absorption,photoluminescence,and time-resolved fluorescence spectrometers were used to analyze their optical properties.The results show that 10%of Zn-doped Au NCs exhibits a 4-fold fluorescence enhancement compared to pure Au NCs,and the quantum yield increases by 2 times.Within 24 h,AuZn NCs showed good stability in H₂O,PBS,and FBS,and showed good photostability within 30 min.The doping of Au,Zn and Cu improves the fluorescence intensity and quantum yield of Ag NCs to a certain extent and show a longer fluorescence lifetime.The doping of 10%Au can increase the fluorescence quantum yield by more than 10 times.The fluorescence quantum yield of 15%Zn-doped Ag NCs is increased by about two times.?3?The biological applications of AuZn NCs,AgAu NCs,AgZn NCs and AgCu NCs were systematically investigatived.At the cellular level,toxicity and radiosensitization of AuZn NCs were measured by cell viability,radiation-induced reactive oxygen species?ROS?levels,and other biological indicators.The results in vitro showed that AuZn NCs display low cytotoxicity and radiation sensitization.In vivo,the distribution of AuZn NCs was measured by in vivo imaging and tumor uptake.In vivo experiments showed that AuZn NCs have better targeting to tumors and can be rapidly excreted by the kidneys.The cell imaging of Ag NCs,AgAu NCs,AgZn NCs,and AgCu NCs were performed.