Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK.
Chemosphere. 2011 Apr;83(4):545-51. doi: 10.1016/j.chemosphere.2010.12.020. Epub 2011 Jan 8.
The fate of nanomaterials when they enter the environment is an issue of increasing concern and thus it is important to know how they interact with natural organic molecules since this may have a significant impact on the particles' behavior. Because of our poor knowledge in this regard, the interaction of ZnO nanoparticles with amino acids of contrasting surface charge, including Histidine (HIS), Glycine (GLY), Aspartic acid (ASP) and Glutamic acid (GLU) which occur commonly in natural habitats, such as the plant root zone, was investigated over a range of pH conditions and concentrations. The addition of the individual amino acid led to significant changes in nanoparticle colloidal zeta potential stability, particle size distribution and the extent of agglomeration. Variations in pH resulted in considerable changes in nanoparticle surface charge and hydrodynamic size. In general, the particle size distribution decreased as the amino acid concentration increased, with more acidic conditions exacerbating this effect. In addition, increased concentrations of amino acids resulted in more stable nanoparticles in aqueous suspensions. Histidine had the greatest effect on colloidal stability, followed by Glycine, Aspartic acid and finally Glutamic acid. This study illustrates how nanoparticle behavior may change in the presence of naturally occurring amino acids, an important consideration when assessing the fate of nanoparticles in the environment. Additionally, utilization of amino acids in industrial processes could reduce particle agglomeration and it could lead to a way of employing more sustainable reagents.
纳米材料进入环境后的命运是一个日益受到关注的问题，因此了解它们与天然有机分子的相互作用非常重要，因为这可能会对颗粒的行为产生重大影响。由于我们在这方面的知识有限，研究了 ZnO 纳米颗粒与在自然栖息地（如植物根区）中常见的具有相反表面电荷的氨基酸（包括组氨酸（HIS）、甘氨酸（GLY）、天冬氨酸（ASP）和谷氨酸（GLU））的相互作用，研究范围涵盖了一系列 pH 值条件和浓度。单独添加氨基酸会导致纳米颗粒胶体动电电位稳定性、颗粒大小分布和聚集程度发生显著变化。pH 值的变化导致纳米颗粒表面电荷和水动力大小发生相当大的变化。一般来说，随着氨基酸浓度的增加，颗粒大小分布减小，而更酸性的条件会加剧这种效应。此外，氨基酸浓度的增加导致水悬浮液中的纳米颗粒更稳定。组氨酸对胶体稳定性的影响最大，其次是甘氨酸、天冬氨酸，最后是谷氨酸。这项研究说明了在存在天然存在的氨基酸的情况下，纳米颗粒的行为可能会发生怎样的变化，这是评估纳米颗粒在环境中命运时需要考虑的一个重要因素。此外，在工业过程中使用氨基酸可以减少颗粒聚集，并且可能会找到更可持续的试剂的使用方法。
