Nigella sativa L. seeds extract assisted synthesis of silver nanoparticles and their antibacterial and catalytic performance

In this research work, a green synthesis method of using a Nigella sativa L. seeds extract as a reductant was adopted for the silver nanoparticles (AgNP) production. The AgNP were produced using a 5 mM silver nitrate mixed with the seeds extract at 25 °C and at 60 °C. It was observed that the AgNP production rate significantly increased at high temperatures. The obtained AgNP were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. SEM depicted an average particle size (42 ± 15 nm) of synthesized AgNP. XRD results further augmented the SEM data and indicated definite crystallinic peaks for synthesized AgNP. The prepared Nigella sativa L. extract assisted AgNP (N.S./AgNP) were further used in the reduction of the MB and 4-nitroaniline dyes as well as in antibacterial studies. It was found that the AgNP successfully transformed the 4-NA and MB to their reductive compounds with high conversion rates of 0.1021 min−1 and 0.4197 min−1, respectively. The antibacterial results showed that the N.S./AgNP have good killing properties against Staphylococcus aureus, Klebsiella pneumonia and Pseudomonas aeruginosa bacteria.