Abstract Green synthesis of nanoparticles (NPs) is a more sustainable, safe, and environmentally friendly method. This study aimed to investigate the synthesis procedure of iron oxide nanoparticles (IONPs) using the seed extract of Nigella sativa (N. sativa) as a strong reducing agent and to estimate their cytotoxic and antibacterial properties. The obtained IONPs were characterized by field-emission scanning electron microscopy, X-ray diffraction, dynamic light scattering (DLS), zeta potential (ZP), and Fourier-transform infrared spectroscopy analyses. The cytotoxicity of the biosynthesized IONPs was demonstrated by the MTT on a Vero cell line. Furthermore, the antibacterial activity of the fabricated biosynthesis metal oxide NPs was tested on Escherichia coli (E. coli) (ATCC 35218) and Staphylococcus aureus (S. aureus) (ATCC 29213) bacterial strains using the Kirby–Bauer disk diffusion method. This study showed the formation of a well-dispersed, highly stable (ZP ζ = −51.8 mV) IO NPs with an average diameter of about 31.45 nm. Moreover, the biosynthetic NPs (IONPs) exhibited a significantly noncytotoxic effect when analyzed by the MTT assay. The biosynthetic NPs (NS-IONPs) exhibited excellent antibacterial activity against E. coli and S. aureus, where the inhibition zones were 12.34 ± 0.58 and 11.52 ± 0.58, respectively.

中文翻译：

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使用 Nigella sativa 种子提取物的氧化铁纳米颗粒的绿色合成、表征、细胞毒性和抗菌活性

摘要 纳米粒子（NPs）的绿色合成是一种更可持续、更安全、更环保的方法。本研究旨在研究使用黑种草 (N. sativa) 的种子提取物作为强还原剂合成氧化铁纳米颗粒 (IONPs) 的过程，并评估它们的细胞毒性和抗菌特性。通过场发射扫描电子显微镜、X 射线衍射、动态光散射 (DLS)、zeta 电位 (ZP) 和傅里叶变换红外光谱分析对获得的 IONP 进行了表征。MTT 在 Vero 细胞系上证明了生物合成的 IONP 的细胞毒性。此外，制备的生物合成金属氧化物纳米粒子的抗菌活性在大肠杆菌（E.coli）（ATCC 35218）和金黄色葡萄球菌（S. aureus) (ATCC 29213) 使用 Kirby-Bauer 圆盘扩散法的细菌菌株。该研究表明形成了平均直径约为 31.45 nm 的分散良好、高度稳定的 (ZP ζ = -51.8 mV) IO NPs。此外，当通过 MTT 测定分析时，生物合成 NPs (IONPs) 表现出显着的非细胞毒性作用。生物合成 NPs (NS-IONPs) 对大肠杆菌和金黄色葡萄球菌表现出优异的抗菌活性，抑制区分别为 12.34 ± 0.58 和 11.52 ± 0.58。