The aim of this research is to conduct green synthesis of silver nanoparticles in an eco-friendly, economical and more effective approach using plant extract as well as to study the effect of the preparation conditions on the size of synthesized nanoparticles and its antibacterial activity. In this study, silver nanoparticles have been synthesized by reduction method using aqueous silver nitrate solution and aqueous extract of . Then, their characterization has been studied by several methods, such as visual inspection, UV–Vis spectroscopy, dynamic light scattering and scanning electron microscope. In addition, the effects of (silver nitrate: extract) ratio, type extract, temperature and reaction time have been studied on the size of prepared silver nanoparticles. Furthermore, the antibacterial effect of these nanoparticles was studied on using micro-dilution method and determination the Minimum Inhibitory Concentration (MIC). The results showed that the silver nanoparticles prepared using extract have reported visible yellowish brown color formation and the absorption peak at 460 nm indicated the biosynthesis of silver nanoparticles. Moreover, they have average diameter (88.11) nm and the polydispersity index (PdI) was suitable. The optimal conditions for synthesis silver nanoparticles were using aqueous extract in 9:1 ratio (silver nitrate: extract) at 35 °C for 48 h. These silver nanoparticles were stable in the in the fridge at 5 °C for a maximum period of 15 days. On the other hand, the antibacterial tests showed that these nanoparticles have high antibacterial activity where the MIC value ranged between (3.125–12.5) μg/ml on isolates. We conclude that extract is considered effective as a reducing agent for the preparation of stable silver nanoparticles in certain conditions and this silver nanoparticle has a high antibacterial activity.

中文翻译：

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蓝藻水提取物绿色合成纳米银及其抗菌活性


本研究的目的是利用植物提取物以环保、经济、更有效的方式绿色合成纳米银颗粒，并研究制备条件对合成纳米颗粒尺寸及其抗菌活性的影响。在这项研究中，使用硝酸银水溶液和水提取物通过还原法合成了银纳米颗粒。然后，通过目视检查、紫外可见光谱、动态光散射和扫描电子显微镜等多种方法对其表征进行了研究。此外，还研究了（硝酸银：提取物）比例、提取物类型、温度和反应时间对制备的银纳米粒子尺寸的影响。此外，通过微量稀释法和测定最低抑菌浓度（MIC）研究了这些纳米颗粒的抗菌效果。结果表明，使用提取物制备的银纳米颗粒形成了可见的黄棕色颜色，460 nm 处的吸收峰表明银纳米颗粒的生物合成。此外，它们的平均直径为(88.11)nm，多分散指数(PdI)合适。合成银纳米粒子的最佳条件是使用9:1比例的水提取物（硝酸银：提取物）在35℃下反应48小时。这些银纳米粒子在 5 °C 的冰箱中可稳定保存最长 15 天。另一方面，抗菌测试表明这些纳米颗粒具有较高的抗菌活性，其对分离株的 MIC 值在（3.125-12.5）μg/ml 之间。 我们得出的结论是，提取物被认为是在某些条件下制备稳定的银纳米颗粒的有效还原剂，并且这种银纳米颗粒具有很高的抗菌活性。