Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, People's Republic of China.
Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, People's Republic of China.
Environ Pollut. 2018 Nov;242(Pt B):1206-1216. doi: 10.1016/j.envpol.2018.08.005. Epub 2018 Aug 7.
The presence of abundant extracellular polymeric substances (EPS) play a vital role in affecting heteroaggregation process and toxicity of nanoparticles (NPs) to Microcystis aeruginosa. Interactions between n-CeO and cyanobacteria with/without EPS and the toxicity of n-CeO to M. aeruginosa were investigated in this study. Aggregation kinetics of n-CeO under both soluble EPS (SEPS) and bound EPS (BEPS) indicated the presence of EPS could induced the formation of EPS-NPs aggregates. Heteroaggregation between cells and n-CeO was confirmed through co-settling experiment and SEM-EDS observation. SEPS contributed to the observable heteroaggregation using spectral measurement. Heteroaggregation between cells and n-CeO2 under no BEPS was hardly obtained through spectral measurement, but SEM-EDS observation convinced this process. And the DLVO theory explained this heteroaggregation process under various EPS conditions, where the energy barrier decreased with gradual EPS extraction. In addition, the order for 96 h half growth inhibition concentration (IC) was Raw M9 > M9-SEPS > M9+BEPS > M9-BEPS. These results revealed that not all heteroaggregation between cell-NPs can lead to the NPs toxicity to cells. BEPS act more important role in buffering against the toxicity of NPs from ambient adverse factors, but SEPS increase the stability of NPs which could aggravate the adverse effects of NPs in the environment.
大量细胞外多聚物（EPS）的存在在影响纳米颗粒（NPs）对铜绿微囊藻的异质聚集过程和毒性方面起着至关重要的作用。本研究考察了 n-CeO 与含/不含 EPS 的蓝藻之间的相互作用，以及 n-CeO 对铜绿微囊藻的毒性。n-CeO 在可溶性 EPS（SEPS）和结合 EPS（BEPS）下的聚集动力学表明，EPS 的存在可以诱导 EPS-NPs 聚集的形成。通过共沉降实验和 SEM-EDS 观察证实了细胞与 n-CeO 之间的异质聚集。通过光谱测量证实了 SEPS 对可观察到的异质聚集的贡献。在没有 BEPS 的情况下，通过光谱测量几乎无法获得细胞与 n-CeO2 之间的异质聚集，但 SEM-EDS 观察证实了这一过程。DLVO 理论解释了在各种 EPS 条件下的异质聚集过程，其中能量势垒随着 EPS 的逐渐提取而降低。此外，96 小时半抑制浓度（IC）的顺序为：原 M9＞M9-SEPS＞M9+BEPS＞M9-BEPS。这些结果表明，并非所有细胞-NPs 之间的异质聚集都能导致 NPs 对细胞的毒性。BEPS 在缓冲 NPs 来自环境不利因素的毒性方面起着更重要的作用，但 SEPS 增加了 NPs 的稳定性，从而可能加剧 NPs 在环境中的不利影响。
