Environ Sci Technol. 2015 Jan 20;49(2):932-9. doi: 10.1021/es504730k.
Discharged oxide nanoparticles (NPs) have been shown toxic to unicellular algae, yet the research on heteroagglomeration between NPs and cells as an important precondition of the toxicity is scarce. This study for the first time investigated heteroagglomerations between various NPs and algal cells (Chlorella pyrenoidosa) and analyzed influencing factors including pH and ionic strength (IS) through cosettling experiment, transmission electron microscopic (TEM) observation, and Derjaguin–Landau–Verwey–Overbeek (DLVO) calculation. The examined NPs included anatase and rutile TiO2, microporous and spherical SiO2, and α-form and β-form Al2O3. The results of cosettling experiments coincided well with the TEM observations, whereas the DLVO theory could only partly explain the NP–cell heteroagglomerations. The NP–cell heteroagglomeration for rutile TiO2 and β-form Al2O3 was weak and insensitive to pH or IS. Preferential heteroagglomeration occurred at low pH or high IS for microporous SiO2, while marked heteroagglomeration only occurred under the neutral and low IS condition for anatase TiO2. The heteroagglomeration for spherical SiO2 was insensitive to pH but increased with increasing IS, while the heteroagglomeration for α-form Al2O3 occurred at low pH and irrelevant to IS. The work will shed new light on the bionano interfacial interaction and help to understand biological effects of NPs.
已证明释放的氧化纳米颗粒（NPs）对单细胞藻类具有毒性，但关于 NPs 与细胞之间的异质凝聚作为毒性的重要前提条件的研究却很少。本研究首次调查了各种 NPs 与藻类细胞（蛋白核小球藻）之间的异质凝聚，并通过共沉降实验、透射电子显微镜（TEM）观察和德加古林-朗道-维尔韦-奥弗贝克（DLVO）计算分析了包括 pH 值和离子强度（IS）在内的影响因素。所研究的 NPs 包括锐钛矿和金红石 TiO2、微孔和球形 SiO2 以及α-型和β-型 Al2O3。共沉降实验的结果与 TEM 观察结果吻合良好，而 DLVO 理论只能部分解释 NP-细胞异质凝聚。金红石 TiO2 和β-型 Al2O3 的 NP-细胞异质凝聚较弱，对 pH 值或 IS 不敏感。对于微孔 SiO2，优先发生异质凝聚在低 pH 值或高 IS 值下，而对于锐钛矿 TiO2，则仅在中性和低 IS 值条件下发生明显的异质凝聚。球形 SiO2 的异质凝聚对 pH 值不敏感，但随 IS 值的增加而增加，而α-型 Al2O3 的异质凝聚发生在低 pH 值且与 IS 值无关。这项工作将为生物纳米界面相互作用提供新的认识，并有助于理解 NPs 的生物学效应。
