Insecticidal and fungicidal performance of bio-fabricated silver and gold nanoparticles

Abstract

The current article focuses on the synthesis of silver and gold nanoparticles by different parts (bark, leaf, and flower) of Moringa oleifera, and their insecticidal activities against larvae of culex quinquefasciatus and Aedes aegypti mosquitoes and fungicidal activity against Aspergillus sp. Both the nanoparticles were characterized by several analytical instruments such as UV–Visible spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM). A clear signature of surface plasmon resonance of both Ag and Au nanoparticles was recorded at 415 nm and 545 nm with respective salt solution and bark extract of Moringa oleifera, respectively. The non-uniform spherical size of both Ag and Au nanoparticles was confirmed from TEM, XRD, and EDX-FESEM studies. Similarly, the existence of significant functional groups was also identified by FTIR analysis. The larvicidal activity of both the nanoparticles exhibited nonsignificant difference (for both LC50 and LC90) at 24 and 48 h of incubation for both the mosquito species. However, antifungal activity of Ag and Au nanoparticles against Aspergillus sp. at higher concentration (200 mg/L) was exhibited with the inhibition zone 0.502 and 0.125 cm2, respectively. The toxicological study also revealed that both nanoparticles had no adverse effect on the nontarget species, Chironomus sp. Therefore, it could be concluded that both the synthesized nanoparticles have enough potentiality in respect of larvicidal and fungicidal activities.