▎ 摘　　要

NOVELTY - Preparing a competitive immunosensor involves adding 3-aminopropyl)triethoxysilane (APTES) to silver doped silicon dioxide nanoparticles (Ag@SiO2 NPs) under stirring at 15-35℃ for 10-15 hours to obtain aminated Ag@SiO2 NPs solution, taking nitrogen-sulfur doped graphene quantum dots (N,S-GQDs) suspension and the aminated Ag@SiO2 NPs solution in the reactor under stirring continuously at 15-35℃ for 10-15 hours, and separating the unconnected N,S-GQDs quantum dots, and then centrifuging and freeze-drying to obtain the Ag@SiO2@N,S-GQDs nanocomposite. The prepared Ag@SiO2@N,S-GQDs nanocomposite is dissolved in water and ultrasonically dispersed to prepare a concentration of 1mg/mL Ag@SiO2@N,S-GQDs solution, Ag@SiO2@N,S-GQDs(1mg/mL) solution, added 1,2-dichloroethane under stirring at 15-35℃ to activate free carboxylic acid groups on Ag@SiO2@N, S-GQD, added antigen at 30-40℃ in the dark for 1-3 hours to get Ag@SiO2@N,S-GQDs-antigen fluorescent probe solution. USE - Method for preparing a competitive immunosensor for fluorescence resonance energy transfer used for detecting biomarkers in human serum samples (claimed). ADVANTAGE - The prepared competitive immunosensor avoids complicated operation and expensive instruments shorten the detection time and have the characteristics of low detection limit, high sensitivity, simple operation, and high specificity. DETAILED DESCRIPTION - Preparing a competitive immunosensor involves adding 3-aminopropyl)triethoxysilane (APTES) to silver doped silicon dioxide nanoparticles (Ag@SiO2 NPs) under stirring at 15-35℃ for 10-15 hours to obtain aminated Ag@SiO2 NPs solution, taking nitrogen-sulfur doped graphene quantum dots (N,S-GQDs) suspension and the aminated Ag@SiO2 NPs solution in the reactor under stirring continuously at 15-35℃ for 10-15 hours, and separating the unconnected N,S-GQDs quantum dots, and then centrifuging and freeze-drying to obtain the Ag@SiO2@N,S-GQDs nanocomposite. The prepared Ag@SiO2@N,S-GQDs nanocomposite is dissolved in water and ultrasonically dispersed to prepare a concentration of 1mg/mL Ag@SiO2@N,S-GQDs solution, Ag@SiO2@N,S-GQDs(1mg/mL) solution, added 1,2-dichloroethane under stirring at 15-35℃ to activate free carboxylic acid groups on Ag@SiO2@N, S-GQD, added antigen at 30-40℃ in the dark for 1-3 hours to get Ag@SiO2@N,S-GQDs-antigen fluorescent probe solution. The pH of the solution is adjusted to 7 with 0.1mol/L potassium carbonate or 0.1mmol/L hydrochloric acid, then added the antibody under stirring at 30-40℃ for 1-5 hours to obtain an antibody-gold nanoparticles probe solution. The target solution is added to the antibody probe solution, mixed well, and reacted at 30-40℃ for 20-60 minutes, added the Ag@SiO2 @N,S-GQDs-antigen fluorescent probe solution, and reacted at a certain temperature for a period of time to obtain the fluorescent resonance energy transfer competitive immunosensor.