Silver and gold nanoparticles are promising tools for medical and industrial applications; therefore, their ecotoxicity should be carefully examined. There are many publications that discuss their effects at high concentrations on various organisms, while the effects of low doses have not been sufficiently investigated. In this paper, the effects of low concentrations of silver (12 nm) and gold (4.7 nm) nanoparticles coated with polyethylene glycol on Spirulina platensis biomass growth, biochemical composition, and antioxidant activity were investigated. The spirulina cultivation medium was supplemented with nanoparticles in the concentration range of 0.025–0.5 µM. The given concentrations stimulated spirulina biomass, but the content of proteins, carbohydrates, and auxiliary pigments was insignificantly affected by the presence of nanoparticles in the cultivation medium. Gold nanoparticles at a concentration of 0.5 µM produced a pronounced effect on the lipid content. Transmission electron microscope images demonstrated that the nanoparticles penetrate inside the cells and cause ultrastructural changes. The nanoparticles were characterized using several well-known techniques. The results confirmed a negative effect of low concentrations of metal nanoparticles on spirulina. This effect could be indiscernible when studying the biomass viability, but determination of the ultrastructure of the cell and the biochemical composition of the biomass could reveal it.

中文翻译：

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PEG包覆的银和金纳米颗粒在密闭系统中生长对螺旋藻生物量的影响

银和金的纳米颗粒是用于医疗和工业应用的有前途的工具。因此，应仔细检查其生态毒性。有许多出版物讨论了高浓度它们对各种生物的影响，而低剂量的影响尚未得到充分研究。本文研究了低浓度银（12 nm）和金（4.7 nm）纳米粒子的聚乙二醇涂层对螺旋藻的影响研究了生物量的增长，生化组成和抗氧化活性。螺旋藻培养基中添加了浓度范围为0.025-0.5 µM的纳米颗粒。给定的浓度刺激了螺旋藻的生物量，但是蛋白质，碳水化合物和辅助色素的含量不受培养基中纳米颗粒存在的影响。浓度为0.5 µM的金纳米颗粒对脂质含量产生了显着影响。透射电子显微镜图像显示纳米颗粒渗透细胞内部并引起超微结构变化。使用几种众所周知的技术来表征纳米颗粒。结果证实了低浓度的金属纳米颗粒对螺旋藻的负面影响。