Green synthesis of AgNP–ligand complexes and their toxicological effects on Nilaparvata lugens

Abstract

Abstract Background Despite developments in nanotechnology for use in the pharmaceutical field, there is still a need for implementation of this technology in agrochemistry. In this study, silver nanoparticles (AgNPs) were successfully prepared by a facile and an eco-friendly route using two different ligands, 2ʹ-amino-1,1ʹ:4ʹ,1″-terphenyl-3,3″,5,5″-tetracarboxylic acid (H4L) and 1,3,6,8-tetrakis (p-benzoic acid)-pyrene (TBAPy), as reducing agents. The physiochemical properties of the as-obtained AgNPs were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The toxicity of H4L–AgNP and TBAPy–AgNP against the brown planthopper (BPH, Nilaparvata lugens) was also measured. Results SEM and TEM analyses demonstrated the formation of quasi-spherical AgNP structures in the presence of H4L and TBAPy. Insecticidal assays showed that TBAPy is less effective against N. lugens, with a median lethal concentration (LC50) of 810 mg/L, while the toxicity of H4L increased and their LC50 reached 786 mg/L 168 h posttreatment at a high concentration of 2000 mg/L. H4L–AgNPs were also highly toxic at a low concentration of 20 mg/L, with LC50 = ~ 3.9 mg/L 168 h posttreatment, while TBAPy–AgNPs exhibited less toxicity at the same concentration, with LC50 = ~ 4.6 mg/L. Conclusions These results suggest that the synthesized AgNPs using the two ligands may be a safe and cheaper method compared with chemical insecticides for protection of rice plants from pests and has potential as an effective insecticide in the N. lugens pest management program.

Keywords

• Nanotechnology
• Organic ligands
• Silver nanoparticles
• Insecticidal effect
• Nilaparvata lugens