Self-Assembled MoS₂/ssDNA Nanostructures for the Capacitive Aptasensing of Acetamiprid Insecticide

The aim of this work is to detect acetamiprid using electrochemical capacitance spectroscopy, which is widely used as a pesticide in agriculture and is harmful to humans. We have designed aptasensing platform based on the adsorption of a DNA aptamer on lipoic acid-modified MoS₂ nano-sheets. The biosensor takes advantage of the high affinity of single-stranded DNA sequences to MoS₂ nano-sheets. The stability of DNA on MoS₂ nano-sheets is assured by covalent attachment to lipoic acid that forms self-assembled layer on MoS₂ surface. The biosensor exhibits excellent capacitance performances owing to its large effective surface area making it interesting material for capacitive transduction system. The impedance-derived capacitance varies with the increasing concentrations of acetamiprid that can be attributed to the aptamer desorption from the MoS₂ nanosheets facilitating ion diffusion into MoS₂ interlayers. The developed device showed high analytical performances for acetamiprid detection on electrochemical impedance spectroscopy EIS- derived capacitance variation and high selectivity toward the target in presence of other pesticides. Real sample analysis of food stuff such as tomatoes is demonstrated which open the way to their use for monitoring of food contaminants by tailoring the aptamer. View Full-Text