The aim of this study was the development of a non-toxic, biosynthetic antimicrobial agent which selectively acts on only one type of microorganism, and preserves the microbiota. Antimicrobial performance of biosynthesized silver nanoparticles (Ag NPs) by horsetail (Equisetum arvense L.) extract was examined against Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus, as well as yeasts Candida albicans and Saccharomyces boulardii. Also, the cytotoxicity of Ag NPs was examined toward pre-osteoblast cells. The synthetic conditions—concentration of extract, temperature, and pH—were optimized to prepare silver colloids with different particle size distributions and long-term stability. The obtained samples were characterized using transmission electron microscopy, X-ray diffraction analysis, and absorption spectroscopy. The smaller-sized Ag NPs (~ 10–20 nm), prepared at a lower temperature (20 °C), showed better antimicrobial performance against E. coli compared to larger ones (~ 40–60 nm), prepared at high temperature (100 °C). On the other hand, both samples did not display any toxic action against bacteria S. aureus, or yeasts C. albicans and S. boulardii. Non-cytotoxic behavior of Ag NPs toward pre-osteoblast cells was observed for the concentrations of silver ≤ 2.25 and ≤ 4.5 mg L⁻¹ for 10–20 and 40–60 nm-sized Ag NPs, respectively. Biosynthesized Ag NPs by horsetail extract display selective toxic action against E. coli at the ecologically acceptable concentration level.

中文翻译：

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马尾提取物对大肠杆菌的生物合成银纳米颗粒的选择性抗菌性能

这项研究的目的是开发一种无毒，生物合成的抗微生物剂，该剂可选择性地仅作用于一种类型的微生物，并能保留微生物。由生物合成的马尾银纳米颗粒（银纳米颗粒）的抗微生物性能（问荆L.）提取物，检查对革兰氏阴性菌大肠杆菌和革兰氏阳性菌金黄色葡萄球菌，以及酵母白色念珠菌和布拉酵母菌。同样，检查了Ag NPs对成骨细胞的细胞毒性。优化了合成条件（提取物的浓度，温度和pH），以制备具有不同粒径分布和长期稳定性的银胶体。使用透射电子显微镜，X射线衍射分析和吸收光谱对获得的样品进行表征。在较低温度（20°C）下制备的较小尺寸的Ag NP（〜10–20 nm），与在高温下制备的较大（约40–60 nm）相比，对大肠杆菌表现出更好的抗菌性能。 100°C）。另一方面，两个样品均未表现出对细菌金黄色葡萄球菌或酵母白色念珠菌和bo.d. Sularularii的任何毒性作用。。银纳米颗粒对成骨细胞的无细胞毒性行为在银浓度分别为10-20和40-60 nm的银纳米颗粒中分别≤2.25和≤4.5 mg L ^-1时观察到。马尾提取物生物合成的银纳米颗粒在生态可接受的浓度水平下对大肠杆菌表现出选择性的毒性作用。