Aptamer-functionalized CdTe:Zn2+ quantum dots for the detection of tomato systemin

Abstract

With the advantages of excellent optical properties and biocompatibility, DNA-functionalized quantum dots (QDs) have been widely applied in biosensing and bioimaging. Systemin is an important class of plant peptide hormone that was first identified in plants. In this paper, we have synthesized aptamer-functionalized Zn²⁺ doped CdTe QDs through a facile one-pot hydrothermal route, and a fluorescent aptasensor based on graphene oxide (GO) is developed for the detection of tomato systemin (TomSys) with aptamer recognition properties. In the absence of TomSys, the aptamer-functionalized QDs are adsorbed on the surface of GO and the fluorescence is efficiently quenched, while in the presence of TomSys, the specific binding of TomSys with its aptamer competitively releases aptamer-functionalized QDs from the GO surface, leading to the recovery of QDs fluorescence. The results demonstrate that the simple, rapid and cost-efficient biosensor possesses satisfactory sensitivity and selectivity for the detection of TomSys.