The Fabrication Of Carbon Dots/Silica Hybrid Porous Spheres And Their Effect As Supports For Enzyme

Carbon quantum dots are a new type of nano-materials with carbon as the skeleton structure.As a new luminescent material,compared with conventional semiconductor quantum dots or organic pigment molecules,carbon dots are not only less toxic,biocompatible,and inexpensive,easy to large-scale synthesis and other advantages,but also show unmatched advantages such as adjustable luminous range,high fluorescence quantum efficiency,and good light stability.On the other hand,because of their structural stability,non-toxicity,and biocompatibility,porous silica are widely used as one of the ideal carriers materials for pharmaceutical molecules or biological enzymes.They not only largely maintain the original activity of the biological enzyme,but also help the enzyme to exert its long-term repeated usage.This topic is to explore the preparation of porous silica supports with optical properties through binding with carbon quantum dots,and study their effect for regulating the activity of the loaded enzymes.The main research contents are summarized as follows:(1)The influence of surface modification of silica on the complex with carbon quantum dots.Solid silica particles were modified with silanes under different conditions and used to insitu generate carbon dots.The effect of surface modification on the formation of carbon dots and the optical properties of nano-silica@carbon dots were studied.After structural analysis and comparison,it was found that the silica particles obtained by the pre-modification method(that is,adding aminosilane in the process of synthesizing particles)may lead to the synthesis of carbon dots with higher relative content and uniform distributution.The content of carbon dots in the silica can reach about 35%,and the pre-modified silica@carbon dots exhibit more stable light-emitting characteristics.While,the light emission position and intensity of the postmodified silica@carbon dots have changed significantly at different excitation wavelengths.These results indicate that the different surface states of nano-silica particles may bring different effects on the in-situ combination of carbon dots,which may provide research basis on the study of the application performance of the optical silica carriers.(2)The process of dissolving and regenerating silica spheres is used to control the preparation of hollow porous silica sphere particles composited with carbon quantum dots.The nano-silica particles with amino-modification are used to fabricate the hybrid hollow spheres of silica and carbon dots(hollow silica@carbon dots)based on a one-step hydrothermal process.It was found that the hollow silica spheres from the post-modification method(that is,adding aminosilane after synthesizing the particles)facilitate the synthesis of carbon dots with higher content and uniform structure on the surface.The content of carbon dots can reach about 25%at the maximum.The hollow silica@carbon dots exhibit strong luminescence under different excitation wavelengths,in which the highest intensity is under excitation at 375 nm.(3)The effect of silica-carbon quantum dot composite particles on biological enzyme activity.The electron gain and loss ability of silica@carbon dots complex is varied under light irradiation at different wavelength.When loaded with biological enzyme,the photo-induced electron gain and loss characteristics of carbon quantum dots strongly affect the reaction activity of biological enzyme.At different light irradiation conditions,the front modified solid silica@carbon dots complex,the post modified solid silica@carbon dots complex and the post modified hollow silica @carbon dots complex make the lipase the strongest vitality increased by 6.1%,2% and 18.2% respectively.The results show that the post-modified hollow silica@carbon dots complex has a significant effect on the improvement of lipase activity.