School of Energy and Environment and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong China.
Research Centre for the Oceans and Human Health, City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057, China.
Environ Sci Technol. 2021 Apr 20;55(8):5143-5151. doi: 10.1021/acs.est.0c08588. Epub 2021 Mar 16.
Widely applied silver nanoparticles (AgNPs) can have potentially detrimental impacts on aquatic organisms. Unicellular algae as primary producers can interact with AgNPs and initiate their transfer along food chains. Herein, we demonstrate that AgNPs were internalized in a freshwater phytoplankton species , but the entrance pathways varied with their surface coatings. Citrate-coated AgNPs (Cit-AgNPs) were internalized mainly through the apical zone of the cell near the flagella, whereas the aggregation-induced emission fluorogen (AIEgen)-coated AgNPs (AIE-AgNPs) were internalized through endocytosis. The internalized AgNPs were dissolved intracellularly and the released Ag was distributed heterogeneously in the cytoplasm, in contrast to the directly accumulated Ag which displayed a diffuse cytoplasmic distribution pattern. We then further visualized and quantified the trophic transfer of AgNPs from the alga to the zooplanktonic species . Both trophically transferred Ag and AgNPs were concentrated in the gut regions of as a result of the direct ingestion of food particles. After ingestion, about 95% of the trophically transferred Ag was eliminated. Retention of AIE-AgNPs by daphnids was relatively higher than that of Cit-AgNPs due to their lower dissolution of Ag. The present study provides direct evidence for the internalization of AgNPs in unicellular algae and demonstrates that the biological transport of trophically transferred of AgNPs is related to the different surface coatings of NPs.
广泛应用的银纳米颗粒 (AgNPs) 可能对水生生物产生潜在的有害影响。作为初级生产者的单细胞藻类可以与 AgNPs 相互作用，并启动它们沿着食物链的转移。在此，我们证明 AgNPs 被一种淡水浮游植物吸收，但进入途径因表面涂层而异。柠檬酸涂层的 AgNPs（Cit-AgNPs）主要通过靠近鞭毛的细胞顶区被内化，而聚集诱导发射荧光团（AIEgen）涂层的 AgNPs（AIE-AgNPs）则通过内吞作用被内化。内化的 AgNPs 在细胞内溶解，释放的 Ag 不均匀地分布在细胞质中，与直接积累的 Ag 形成鲜明对比，后者呈现出弥漫性的细胞质分布模式。然后，我们进一步可视化和量化了 AgNPs 从藻类到浮游动物物种的营养转移。由于直接摄入食物颗粒，两种营养转移的 Ag 和 AgNPs 都集中在 的肠道区域。摄入后，约 95%的营养转移 Ag 被消除。由于 Ag 的溶解较低，水蚤对 AIE-AgNPs 的保留相对较高，而对 Cit-AgNPs 的保留则较低。本研究为 AgNPs 在单细胞藻类中的内化提供了直接证据，并表明营养转移的 AgNPs 的生物传输与 NPs 的不同表面涂层有关。
