Eixenberger Josh E, Anders Catherine B, Hermann Rebecca J, Brown Raquel J, Reddy Kongara M, Punnoose Alex, Wingett Denise G
Biomolecular Sciences Graduate Program, ‡Department of Physics, §Biomolecular Research Center, and ⊥Department of Biological Sciences, Boise State University , Boise, Idaho 83725, United States.
Chem Res Toxicol. 2017 Aug 21;30(8):1641-1651. doi: 10.1021/acs.chemrestox.7b00136. Epub 2017 Aug 11.
Zinc oxide nanoparticles (nZnO) are one of the most highly produced nanomaterials and are used in numerous applications including cosmetics and sunscreens despite reports demonstrating their cytotoxicity. Dissolution is viewed as one of the main sources of nanoparticle (NP) toxicity; however, dissolution studies can be time-intensive to perform and complicated by issues such as particle separation from solution. Our work attempts to overcome some of these challenges by utilizing new methods using UV/vis and fluorescence spectroscopy to quantitatively assess nZnO dissolution in various biologically relevant solutions. All biological buffers tested induce rapid dissolution of nZnO. These buffers, including HEPES, MOPS, and PIPES, are commonly used in cell culture media, cellular imaging solutions, and to maintain physiological pH. Additional studies using X-ray diffraction, FT-IR, X-ray photoelectron spectroscopy, ICP-MS, and TEM were performed to understand how the inclusion of these nonessential media components impacts the behavior of nZnO in RPMI media. From these assessments, we demonstrate that HEPES causes increased dissolution kinetics, boosts the conversion of nZnO into zinc phosphate/carbonate, and, interestingly, alters the structural morphology of the complex precipitates formed with nZnO in cell culture conditions. Cell viability experiments demonstrated that the inclusion of these buffers significantly decrease the viability of Jurkat leukemic cells when challenged with nZnO. This work demonstrates that biologically relevant buffering systems dramatically impact the dynamics of nZnO including dissolution kinetics, morphology, complex precipitate formation, and toxicity profiles.
氧化锌纳米颗粒（nZnO）是产量最高的纳米材料之一，尽管有报道表明其具有细胞毒性，但仍被用于包括化妆品和防晒霜在内的众多应用中。溶解被视为纳米颗粒（NP）毒性的主要来源之一；然而，溶解研究可能耗时且因诸如从溶液中分离颗粒等问题而变得复杂。我们的工作试图通过利用紫外/可见光谱和荧光光谱的新方法来克服其中一些挑战，以定量评估nZnO在各种生物相关溶液中的溶解情况。所有测试的生物缓冲液都会促使nZnO快速溶解。这些缓冲液，包括HEPES、MOPS和PIPES，常用于细胞培养基、细胞成像溶液以及维持生理pH值。还进行了使用X射线衍射、傅里叶变换红外光谱、X射线光电子能谱、电感耦合等离子体质谱和透射电子显微镜的额外研究，以了解这些非必需培养基成分的加入如何影响nZnO在RPMI培养基中的行为。从这些评估中，我们证明HEPES会导致溶解动力学增加，促进nZnO向磷酸锌/碳酸锌的转化，有趣的是，还会改变在细胞培养条件下与nZnO形成的复杂沉淀物的结构形态。细胞活力实验表明，当用nZnO处理时，这些缓冲液的加入会显著降低Jurkat白血病细胞的活力。这项工作表明，生物相关的缓冲系统会极大地影响nZnO的动态变化，包括溶解动力学、形态、复杂沉淀物的形成和毒性特征。
