Aptamer induced assembly of fluorescent nitrogen-doped carbon dots on gold nanoparticles for sensitive detection of AFB1

Novel fluorescent nitrogen-doped carbon dots (N,C-dots) were synthesized and assembled on aptamer modified gold nanoparticles (Aptamer/AuNPs) for the super sensitive detection of aflatoxin B-1 (AFB(1)). Positively charged N,C-dots were synthesized by the hydrothermal treatment of pancreatin. The prepared N,C-dots were assembled on aptamer/AuNPs by electrostatic interactions. The fluorescence of the N,C-dots was efficiently quenched. When AFB(1) was added to the assay solution, specific interactions between AFB(1) and the aptamer caused release of the N,C-dots. The fluorescence of the N,C-dots recovered and the intensity increase could be used to calculate the amount of AFB(1) added. The assay exhibits super-high sensitivity with a detection limit of 5 pg/mL (16 pM) and a wide range of linear response of 5 pg/mL to 2.00 ng/mL. A novel aptasensor is thus successfully constructed, it provides an efficient way for sensitive AFB(1) sensing as well as a new technique for aptamer based novel sensor construction. (C) 2015 Elsevier B.V. All rights reserved.