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生物合成纳米银对不同营养级水生生物的毒性研究
Alternative TitleToxicity of Biosynthesized Silver Nanoparticles to Aquat Organisms of Different Trophic Levels
Mehdi Khoshnamvand
Subtype博士
Thesis Advisor刘景富
2019-12
Degree Grantor中国科学院生态环境研究中心
Place of Conferral北京
Degree Name理学博士
Degree Discipline环境科学
Keyword生物合成,毒性,纳米银颗粒,水生生物,营养级 biosynthesis, Toxicity, Silver Nanoparticles, Aquatic Organisms, Trophic Level
Abstract

  近年来,为了减少生产过程的污染,避免人工纳米颗粒的不良影响,采用绿色方法合成纳米颗粒引起广泛的关注。虽然生物合成的纳米颗粒被认为是一种生态友好的产品,但关于它们对水生食物链的影响和毒性的数据仍旧缺乏。本研究利用草本植物紫蜀葵的叶提取物合成了银纳米材料(AR-AgNPs)。在此基础上,首次研究了AR-AgNPs及其前驱体银离子和包裹剂(紫蜀葵叶提取物)对淡水食物链中不同营养级的生物(小球藻、大型水蚤和鱼类斑马鱼的毒性效应。
    首先,采用硝酸银和紫蜀葵叶提取物合成了AR-AgNPs,并采用不同的技术对其进行了表征。随着反应时间的延长,硝酸银和紫蜀葵叶提取物的反应混合物由无色变为褐色,吸收光谱出现在420到460 nm之间。通过60 ℃ 反应7小时,动态光散射(DLS)检测到AR-AgNPs的粒径为49.05 ± 25.34 nm,AR-AgNPs的产率约为100%。透射电子显微镜(TEM)显示AR-AgNPs呈球形和准球形,X射线衍射(XRD)分析显示AR-AgNPs具有面心立方(FCC)晶体结构。并用傅里叶变换红外光谱(FTIR)分析了AR-AgNPs表面的主要官能团。
    其次,以处于第一营养水平的淡水藻类小球藻为模式生物,通过生物量变化和叶绿素a的含量评估了AR-AgNPs对小球藻的毒性效应。为确定AR-AgNPs产生毒性的主要原因,同时考察了AR-AgNPs释放的银离子和AR-AgNPs的包裹剂的紫蜀葵叶提取物的毒性效应。结果表明,AR-AgNPs和银离子均能降低生物量和叶绿素a含量,而包裹剂对这些结果没有影响。AR-AgNPs对小球藻生长抑制的72h-EC50为33.63 ± 2.10 μg/L,高于银离子的72h-EC50(20.12 ± 1.55 μg/L),表明银离子比AR-AgNPs毒性更大。由于从AR-AgNPs释放的银离子量很低,AR-AgNPs对小球藻的毒性起主导作用。
    第三,利用大型蚤(D.magna)评估了AR-AgNP对水生系统浮游动物的毒性作用, 同时研究了Ag+ 和AR-AgNPs的包裹剂的毒性,以识别导致AR-AgNPs毒性的成分。 AR-AgNPs和Ag+ 对D. magna的48小时LC50值分别为1.86 ± 0.12和1.30 ± 0.07 μg/L,表明Ag+ 的毒性高于AR-AgNPs。但是,未观察到包裹剂明显的毒性作用。此外,AR-AgNPs在暴露过程中的离子释放量非常低,因此对大型蚤的毒性的主要是AR-AgNPs自身产生的,而不是源于AR-AgNPs释放的Ag+。此外,大型蚤暴露于AR-AgNPs后,鳃区出现褐色色素,可能是AR-AgNPs积累的结果。
    最后,以高级生物斑马鱼 (Danio rerio) 为模型,通过测定AR-AgNPs对斑马鱼的急性毒性及斑马鱼体内乙酰胆碱酯酶 (AChE) 的活性,评价了AR-AgNPs对斑马鱼的毒性作用。结果表明,AR-AgNPs和Ag+的急性毒性与剂量和时间有关。斑马鱼暴露于AR-AgNPs和Ag+的96小时LC50值分别为10.09 ± 0.05和4.74 ± 3.25 μg/L,说明Ag+ 的毒性更高。此外,AR-AgNPs的包裹剂对斑马鱼的毒性没有显著影响。AR-AgNPs和Ag+虽能显著降低鳃部乙酰胆碱酯酶活性,但不能降低肌肉组织中乙酰胆碱酯酶活性。在暴露于AR-AgNPs的鱼样本中,发现了两种明显的异常,如腹部积水和褪色,尤其是在AR-AgNPs浓度较高的情况下更为显著。

Other Abstract

    To decrease pollution of producing processes and avoid from adverse impacts of engineered nanoparticles (NPs), biosynthesis of NPs with green methods has attracted great attention in recent years. Although biosynthesized-NPs (B-NPs) are regarded as eco-friendly products, there is no data on their influences and toxicity to aquatic food chains. To promote our knowledge in this area, new B-NPs (Alcea rosea-silver nanoparticles (AR-AgNPs)) were produced using leaf extract of herbal plant Alcea rosea. Then, the toxic effects of AR-AgNPs and their precursors such as Ag+ ions and coating agent (A. rosea leaf extract) to aquatic organisms of different trophic levels of a freshwater food chain, including phytoplankton (Chlorella vulgaris), zooplankton (Daphnia magna) and fish (Danio rerio) were investigated for the first time.
    Firstly, AR-AgNPs were synthesized by the reaction of silver nitrate with Alcea rosea leaf extract, and characterized with different techniques. With the extending of reaction time, the reaction mixture of silver nitrate with Alcea rosea leaf extract changed from colorless to brown with the appearance of absorption spectra between 420 and 460 nm. By reaction at 60 °C for 7 h, the formed AR-AgNPs showed a size of 49.05 ± 25.34 nm as detected by dynamic light scattering (DLS), and the yield of AR-AgNPs was about 100%. Transmission electron microscopy (TEM) detection showed the AR-AgNPs were spherical and quasi-spherical in shapes, and X-ray diffraction (XRD) analysis demonstrated the face centered cubic (FCC) and crystalline structure. The major functional groups that coated on AR-AgNPs were analyzed by Fourier transform infrared spectroscopy (FTIR).
    Secondly, the toxic effects of AR AgNPs to the aquatic system was evaluated by using freshwater algae C. vulgaris, a model aquatic organism of the first trophic level, and by using the end-points of the biomass change and chlorophyll a content. The toxic effects of Ag+ ions released from AR AgNPs and A. rosea leaf extract as coating agent of AR AgNPs were also assessed to identify the main cause of the toxicity by AR-AgNPs. The results showed that both AR AgNPs and Ag+ ions could decrease amounts of biomass and chlorophyll a content, while the coating agents had no effects on these studied end-points. The 72 h-EC50 of AR AgNPs on growth inhibition of C. vulgaris was 33.63 ± 2.10 μg/L, which was higher than 72 h-EC50 of Ag+ ions (20.12 ± 1.55 μg/L), showing that Ag+ ions were more toxic thanAR-AgNPs. However, as the amount of Ag+ ions released from AR-AgNPs  was very low, AR-AgNPs played the dominant role in toxicity to C. vulgaris.
    Thirdly, the toxic effects of AR-AgNPs  the aquatic system was evaluated by using water flea D. magna, a model aquatic organism of the second trophic level. The toxicity of Ag+ ions and the coating agents of AR-AgNPs was also studied at the same time to identify the components contributed to the toxicity of AR-AgNPs. The 48-h LC50 values of ARAR--AgNPsAgNPs and Ag+ ions to D. magna were 1.86 ± 0.12 and 1.30 ± 0.07 μg/L, respectively, showing Ag+ ions were more toxic than ARAR--AgNPsAgNPs on Daphnia mortality. However, no significant toxic effect was observed by the coating agent. In addition, the determined ion release from AR-AgNPs  was very low during the exposure, and the main cause of toxicity to D. magna was generated by AR-AgNPs  themselves rather than released Ag+ ions from these AR-AgNPs . After exposure daphnids to AR-AgNPs, brown pigments in the gill area was observed, which may be due to AR-AgNPs accumulation.
    Finally, the toxic effects of AR-AgNPs to the aquatic system was evaluated by using a high-level organism zebrafish (Danio rerio) as a model, and by using acute toxicity and inhibition of muscle and gill acetylcholinesterase (AChE) activity as end-points. Results showed that the acute toxicity of AR-AgNPs and Ag+ ions depended on dose and time. The 96-h LC50 values for AR-AgNPs  and Ag+ ions exposures were 10.09 ± 0.05 and 4.74 ± 3.25 μg/L, respectively, indicating higher toxicity of Ag+ ions. Additionally, the coating agents of AR-AgNPs had no significant effects on the studied toxic end-points. Even though the AR-AgNPs and Ag+ ions could reduce gill AChE activity significantly, they could not reduce the muscle AChE activity. Two clear abnormalities such as ascites and fading color were observed in fish samples exposed to AR-AgNPs, especially at higher concentrations of AR-AgNPs

Pages104
Language中文
Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/42175
Collection环境化学与生态毒理学国家重点实验室
Recommended Citation
GB/T 7714
Mehdi Khoshnamvand. 生物合成纳米银对不同营养级水生生物的毒性研究[D]. 北京. 中国科学院生态环境研究中心,2019.
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