Characterization of silver sulfide nanoparticles from actinobacterial strain (M10A62) and its toxicity against lepidopteran and dipterans insect species

Abstract

In this research, cell-free extracts from magnesite mine-isolated actinobacterial strain (M10A62) were used to produce silver sulfide nanoparticles (Ag2SNPs). Streptomyces minutiscleroticus JX905302, actinobacteria capable of producing Ag2SNPs, was used to synthesize Ag2NPs. The UV–vis range was used to confirm the biosynthesized Ag2NPs; Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDAX), and dynamic light scattering analysis were employed to characterize them further. Surface resonance plasma (SRP) for Ag2SNPs was obtained at 355 nm using UV–visible spectroscopy; FT-IR detected bimolecular and eventually microbial-reduced Ag2SNPs from S. minutiscleroticus culture extract. Furthermore, AFM and TEM analysis confirms that the synthesized Ag2SNPs were spherical in shape. Dynamic light scattering revealed a negatively charged Ag2NPs surface with a diameter of 10 nm. The XRD spectrum showed the crystalline nature of the obtained particles. EDAX revealed a pure crystalline nature, and a significant silver particle signal confirms the presence of metallic silver and sulfide nanoparticles together with the signals of Cu and C atoms. After 40 and 48 h of treatment at 150–200 µg·ml−1, Ag2SNPs produced the highest mortality in Spodoptera litura, H. armigera, Aedes aegypti, and Culex quinquefasciatus larvae. Hence, the biosynthesized Ag2SNPs may be useful for potential pest control in integrated pest management and vector control program as a safer, cost-effective, selective, and environmentally friendly approaches.

Keywords

• actinobacteria
• silver sulfide nanoparticles
• biosynthesis
• insecticidal activity