Synthesis And Fluorescence Of Gold Cluster-Carbon Dot Nanocomposites

Fluorescent probe-based detection has gained much more attention in biological and medical science as well as in medical diagnosis becaus of its advantages of high sensitivity,rapidity and simplicity.With the continuous development of detection techniques,exploration of some new fluorescent probes with high emission and sensing performance is highly desirable.As a widely studied fluorescent nanomaterial,carbon dot has stimulated intence interst,owing to its many superiorities of low cost,simple preparation methods,adjustable fluorescence,and high biocompatibility.At the same time,fluorescent gold nanoclusters have also attracted numerous attention as fluorescent probes due to their diverse ligands,strong fluorescence and high sensitivity.It is of great significance to combine suitable carbon dots with gold clusters to form some nanocomposites as new fluorescent probes,and explore their fluorescence properties and application in detection of trace metal ions.Herein,synthesis and fluorescence properties of gold cluster-carbon dot nanocomposites were investidated.The research contents of this dissertation include two parts:(1)gold nanoclusters with an excitation wavelength-independent emission centered at 595 nm were prepared by using chlorgold acid and glutathione as precusors,meanwhile,carbon dots with an excitation wavelength-independent emission centered at 420 nm were produced by using sodium naphthalene and triethylamine as precusors.Futhermore,by combing the gold clusters and the carbon dots,formation of gold cluster-carbon dot nanocomposites was realized.Atomic force microscope,steady-state and transient fluorescence spectrometers were employed to confirm the sucessful preparation of the nanocomposites and reveal an energy transfer from the gold to the carbon;(2)fluorescence properties of the gold cluster-carbon dot nanocomposites were further studied.The effetc of p H values and temperature on the emission properties of the composites were revealed.More importantly,fluorescent detection of several kingds of metal ions were studied.It was reveaded that the intensity ratio of the 595 nm emision to the 420 nm emission shows a good linear relationship with the Ca2+ ion concenttaion in the range of 20 ?mol/L-100 ?mol/L.Since both gold clusters and carbon dots have high biocompatibility,such nanocomposites have promising application potential as fluorescent probe for Ca2+ ion detection in the field of biology and medicine.