Study And Application Of Silicon Quantum Dots/β-cyclodextrin Copper Fluorescence Cluster

Silicon quantum dots（SiQDs）are a kind of nanomaterials with mature preparation and wide application,and have been a research hotspot in the field of fluorescence.In this paper,the preparation methods and fluorescence detection mechanism of SiQDs were reviewed.SiQDs containing amino groups were hydrothermal synthesized at high temperature using silane coupling agent KH550 as silicon source and ascorbic acid as reducing agent.The particle diameter was about 6 nm,and the quantum yield was 24%.Fluorescence clusters（SiQDs/Cu₂-β-CD）were constructed by self-assembly of amino silicon quantum dots andβ-cyclodextrin copper.The diameter of the fluorescent clusters was about 100 nm.The fluorescence intensity of clusters with different ratios was about 27%-88%of that of silicon quantum dots.The aggregation of Cu₂-β-CD with SiQDs resulted in a significant decrease in the fluorescence intensity,which was affected by p H.Based on the fluorescence cluster（SiQDs/Cu₂-β-CD）coordination between amino and copper ions,sulfhydryl compounds can partially replaced SiQDs to interact with Cu₂-β-CD,which led to the decomposition of the fluorescence clusters.The fluorescence intensity increased,and the fluorescence enhancement rate was positively correlated with the concentration of sulfhydryl compounds,showing a linear relationship.Potassium,sodium,magnesium ions and various amino acids with twice the concentration of sulfhydryl compounds were added to the system,and it was found that the system had good anti-interference ability,and the fluctuation range of the values was within 10%.In addition,when copper ions were combined with SiQDs under acid or alkali conditions,the characteristics of Cu₂-β-CD were quite different from those of fluorescent clusters,which also indicated that Cu₂-β-CD was unique.Fluorescent clusters（SiQDs/Cu₂-β-CD）can be used for fluorescence quantitative detection of sulfhydryl compounds.Copper cyclodextrins in fluorescent clusters can encapsulate heterocyclic compounds.When uric acid（UA）was added to the fluorescent clusters system,the fluorescence intensity decreased by about 30%,and the fluorescence quenching rate was positively correlated with UA content.The concentration of SiQDs was 0.7 mg/m L,Cu₂-β-CD was 2.0 m M,and the volume ratio was 1:2,the fluorescence response was the strongest.The fluorescence stabilization time of UA and fluorescence clusters was 120 min.The anti-interference results of potassium,sodium,magnesium ions and various amino acids with twice the concentration of sulfhydryl compounds showed that the numerical fluctuation was within 6%.When p H=8,the fluorescence clusters were responsive to sulfhydryl compounds,but not to UA.When p H=13,fluorescence clusters only responded to UA.When p H=10,the fluorescence clusters were responsive to both sulfhydryl compounds and UA,indicating that the fluorescence clusters were a platform for the fluorescence detection of sulfhydryl compounds and uric acid which could be regulated by p H.