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

Au NCs exhibit the unique electronic structure and photoluminescence properties,such as quantized charges,discrete energy levels,and photoluminescence.Thus,Au NCs have been widely used in optical sensing,fluorescent labeling,bioimaging as well as some other basic fields,and have received much attention.However,expensive price and weak fluorescence of Au have limited their further application in various fields.In order to improve the luminescence properties of Au NCs and lower production costs,a series of chemical methods have been used,including atom doping,protected ligand exchange and changing reaction conditions.In the work,luminescence intensity of Au NCs have been improved by doping metal atoms into the clusters,and the effect of atom doping on electronic structure and optical characteristics have been discussed.Besides,their application has also been explored.The main contents and results are summarized as follows:1.The ultrasmall CuAu NCs and ZnAu NCs were formed through a chemical doping methods with Cu atoms and Zn atoms doping into Au NCs,respectively.The optical properties of Au NCs,CuAu NCs and ZnAu NCs were studied by means of a series of spectral testing techniques such as UV-vis absorption spectra,emission spectra,luminescence lifetimes as well as quantum yields.The results showed luminescence intensity of CuAu NCs increased two folds,while luminescence intensity of ZnAu NCs increased three folds compared with the undoped-atom Au NCs.In addition,the test results for fluorescence lifetime indicated that CuAu NCs and ZnAu NCs presented long fluorescence lifetime.Furthermore,the fluorescence lifetime of ZnAu NCs was longer than that of Au NCs,which indicated that atom doping made an influence on the optical properties of Au NCs.2.The structural features of the alloy CuAu NCs and ZnAu NCs were studied by means of transmission electron microscope(TEM),matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS)and inductively coupled plasma mass spectrometry(ICP-MS)data analysis.The analysis results implied that these two kinds of luminescent clusters were complex clusters with molecular weight in a certain range.3.In order to explore the applications of these two clusters in the biomedicine,the stability and photostability of CuAu NCs and ZnAu NCs were studied.The results exhibited that the two clusters showed superior stability and excellent photostability,which showed great advantages in fluorescent imaging.To further evaluate the availability of the two clusters,the cytotoxicity assessments and cell imaging experiments were conducted.The study results found that they presented low cytotoxicity,and cound be well applied to bioimaging.