Biosynthesis for the preparation of antimicrobial silver nanoparticles (Ag NPs) is a green method without the use of cytotoxic reducing and surfactant agents. Herein, shape-controlled and well-dispersed Ag NPs were biosynthesized using yeast extract as reducing and capping agents. The synthesized Ag NPs exhibited a uniform spherical shape and fine size, with an average size of 13.8 nm. The biomolecules of reductive amino acids, alpha-linolenic acid, and carbohydrates in yeast extract have a significant role in the formation of Ag NPs, which was proved by the Fourier transform infrared spectroscopy analysis. In addition, amino acids on the surface of Ag NPs carry net negative charges which maximize the electrostatic repulsion interactions in alkaline solution, providing favorable stability for more than a year without precipitation. The Ag NPs in combination treatment with ampicillin reversed the resistance in ampicillin-resistant E. coli cells. These monodispersed Ag NPs could be a promising alternative for the disinfection of multidrug-resistant bacterial strains, and they showed negligible cytotoxicity and good biocompatibility toward Cos-7 cells.

中文翻译：

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使用酵母提取物作为还原剂和加帽剂的银纳米粒子的生物合成和抗菌活性。

制备抗菌银纳米颗粒（Ag NPs）的生物合成是一种绿色方法，无需使用细胞毒性还原剂和表面活性剂。在本文中，使用酵母提取物作为还原剂和加帽剂，生物合成了形状受控且分散良好的Ag NP。合成的Ag NPs显示出均匀的球形和精细的尺寸，平均尺寸为13.8 nm。酵母提取物中的还原性氨基酸，α-亚麻酸和碳水化合物的生物分子在Ag NP的形成中具有重要作用，这通过傅里叶变换红外光谱分析得到了证明。此外，Ag NPs表面的氨基酸带有净负电荷，可使碱性溶液中的静电排斥相互作用最大化，从而在不沉淀的情况下提供超过一年的良好稳定性。与氨苄青霉素联合处理的银纳米颗粒逆转了对氨苄青霉素耐药的大肠杆菌细胞的耐药性。这些单分散的银纳米颗粒可能是消毒多药耐药细菌菌株的有前途的替代方法，它们显示出可忽略的细胞毒性和对Cos-7细胞的良好生物相容性。