Three-dimensional mesoporous dendritic fibrous nanosilica as a highly efficient DNA amplification platform for ultrasensitive detection of chlorpyrifos residues

In this paper, a novel amino-functionalized mesoporous dendritic fibrous nanosilica (NH 2 -DFNS) was used as DNA amplification platforms with DNA generated electrochemical signal as target conversion strategy to establish an electrochemical aptasensor for chlorpyrifos residues. The signal generation was based on the electrochemical reaction between molybdate with phosphate groups on the aptamer molecules, which greatly simplified the signal transduction and preparation steps of aptasensor, so as to improve the sensitivity of the aptasensor. The NH 2 -DFNS was prepared by a simple microemulsion method and characterized by SEM, TEM, FT-IR, BET, as well as XPS techniques. Importantly, the results showed that such a sphere-shaped nanomaterial with three-dimensional (3D) centerradial channels and hierarchical pores supported abundant DNA to amplify the DNA generated signal in the aptasensor. Furthermore, this aptasensor for detection of chlorpyrifos showed good sensitivity with a linear range of 1.0 fM∼1.0 nM, a detection limit of 0.43 fM. In addition, this sensor also possessed excellent specificity, repeatability, and stability. Moreover, this proposed electrochemical aptasensor was successfully used for the detection of chlorpyrifos residues in several practical samples.