The Construction And Application Of Fluorescent Copper Nanoclusters Based On DNA Nanostructures

Copper nanoclusters composed of several to dozens of copper atoms have attracted wide attention to scholars.Compared to quantum dots and organic dyes,copper nanoclusters exhibit excellent photostability,large Stokes shift,and low toxicity.As ideal alternatives to organic fluorescent dyes or fluorescent quantum dots,copper nanoclusters have drawn considerable research interest due to their unique optical properties for use in biological imaging and complex sample system.Copper nanoclusters(Cu NCs)are more favorable for various applications due to their mild synthetic condition,abundant and inexpensive of precursor.To obtain stable Cu NCs,they should be protected from aggregation and oxidation,which is commonly achieved by selecting suitable surface ligands.A few ligands including polymers,DNA,proteins,and peptides have been employed for the synthesis of Cu NCs.In order to synthesize copper nanoclusters with good fluorescence stability and high fluorescence intensity,we have constructed different DNA nanostructures containing template sequences for synthesis of copper nanocluster.The specific content includes the following aspects:1.Construction of copper nanoclusters based on DNA nanoribbons Different DNA nanoribbons were designed based on DNA tile self-assembling.DNA nanoribbons,not only provides programmable binding sites but also specific shapes,are first used as templates to obtain Cu NCs self-assemblies.At the same time,we explore the assembly mechanism of Cu NCs on DNA nanoribbons.2.Performance research and application of copper nanoclusters based on DNA nanoribbons The study found that copper nanoclusters synthesized by DNA nanoribbons had higher fluorescence intensity.We analyzed this phenomenon and studied the effect of different DNA nanostructures on the fluorescence properties of copper nanoclusters.Sulfur ion can quench the fluorescence of copper nanoclusters.Based on this mechanism,we constructed a "turnoff" sulfur ion detection sensor and explored the influence of the position of copper nanoclusters on sulfur ion detection;3.Performance research and application of copper nanoclusters based on snowflake-like DNA assemblies In this study,snowflake-like DNA assemblies was formed through hybridization chain reaction,which was used as a stabilizer to synthesize copper nanoclusters with better fluorescent properties.At the same time,using the fluorescence properties of snowflake-like Cu NCs,we designed a label-free "turn-on" sensor for the detection of actin.