Preparation Of Ag-CDs Nanoparticles And Their Catalytic And Optical Properties

As a new type of carbon nanomaterials,carbon dots?CDs?have attracted extensive attention since they were first synthesized in 2004.Various CDs with different properties have been designed and applied in bioimaging,photothermal therapy,and optoelectronic devices.In recent years,nanocomposites based on semiconductor/CDs and noble metal/CDs have been widely stydied.Some nanocomposites exhibit surface enhanced Raman scattering?SERS?enhancement,which can improve the sensitivity of SERS detection.Some nanocomposites with excellent nanozyme activities can be used as the alternative of natural enzymes,which can avoid the disadvantages of natural enzymes.CDs possess excellent hydrophilicity and favorable biocompatibility.The nanocomposites based on CDs can be used as carriers of hydrophobic molecules.Based on the analysis above,the research direction of this subject is determined to synthesize silver-carbon dots?Ag-CDs?nanoparticles with excellent peroxidase-like and SERS activities and use Ag-CDs nanoparticles for uric acid detection and enhanced photodynamic therapy.The research contents are as follows:?1?CDs with the diameter about 2.5 nm were synthesized through hydrothermal method.Core-shell Ag-CDs nanoparticles were fabricated by reducing AgNO₃ with CDs.Ag-CDs nanoparticles exhibit SERS enhancement because of the enhanced electromagnetic field.Due to the electron transfer between CDs and Ag NPs,Ag-CDs nanoparticles exhibit peroxidase-like catalytic activity.Uric acid was detected using Ag-CDs nanoparticles as catalyst and SERS substrate at the same time.?2?The carboxyl groups of Ce6 were activated by EDC/NHS to attach Ce6 on Ag-CDs nanoparticles.Ag-CDs nanoparticles can decompose H₂O₂ into·OH radicals and O₂.This provides sufficient oxygen source for the photodynamic process of Ce6.1,3-diphenyl isobenzofuran was used to explore the photodynamic effect of Ce6 and Ag-CDs-Ce6 nanocomposites.