Rocco Gasco, Isabelle A. M. Worms, Arin Kantarciyan, Vera I Slaveykova
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引用次数: 0
Abstract
Silver nanoparticles (nAg) are extensively used across various fields and are frequently introduced into aquatic environments, where their behavior depends on environmental conditions. Extracellular polymeric substances (EPS) derived from aquatic organisms, such as diatoms, could play an important yet to be explored role in shaping the fate of nAg in aquatic environment. This study investigates the interactions between EPS, particularly those from the diatom Cyclotella meneghiniana, and citrate-coated nAg. The main objective is to understand how EPS influence the behaviours of nAg in freshwater settings, in terms of modulation of the nAg surface properties, colloidal stability and dissolution. To achieve these objectives a combination of the state-of-the-art spectroscopic and imaging techniques was employed. nAg was incubated with EPS isolated from an axenic C. meneghiniana culture, and their interactions were explored in a simulated freshwater environment over both short-term (0-2 hours) and long-term (0-72 hours) periods. The study focused on the changes in nAg, examining surface modulation, colloidal stability, dissolution, EPS adsorption on nAg, and the resulting ecocorona formation.The results indicate that EPS enhance the colloidal stability of nAg and decrease their dissolution in synthetic freshwater by adsorbing onto their surface and inducing steric repulsion between nAg particles. Visualization of the eco-corona formed by diatom EPS on nAg and its impact on aggregation processes is achieved through transmission electron microscopy. The formation of the EPS corona is attributed to the presence of diverse biopolymers within EPS, particularly proteins and polysaccharides. Fluorescence quenching studies on protein fluorophores demonstrate the formation, through hydrophobic interactions, of protein-nAg complex, further confirmed by AF4-DAD-FLD-ICP-MS. In a broader context, the results of this mechanistic study imply that diatoms, through the release of EPS, may significantly influence the destiny and possibly the bioavailability of nAg in EPS-abundant aquatic environments.
纳米银(nAg)被广泛应用于各个领域,并经常被引入水生环境,其行为取决于环境条件。来自硅藻等水生生物的胞外高分子物质(EPS)在影响 nAg 在水生环境中的归宿方面可能发挥着重要作用,但这一作用尚待探索。本研究调查了 EPS(尤其是硅藻 Cyclotella meneghiniana 中的 EPS)与柠檬酸盐涂层 nAg 之间的相互作用。主要目的是了解 EPS 如何在调节 nAg 表面特性、胶体稳定性和溶解性方面影响 nAg 在淡水环境中的行为。将 nAg 与从 C. meneghiniana 轴向培养物中分离出来的 EPS 一起培养,并在模拟淡水环境中探索它们在短期(0-2 小时)和长期(0-72 小时)内的相互作用。结果表明,EPS 通过吸附在 nAg 表面和诱导 nAg 颗粒之间的立体排斥,增强了 nAg 的胶体稳定性,并降低了它们在合成淡水中的溶解度。通过透射电子显微镜,可以观察到硅藻 EPS 在 nAg 上形成的生态电晕及其对聚集过程的影响。EPS 电晕的形成是由于 EPS 中存在多种生物聚合物,特别是蛋白质和多糖。对蛋白质荧光团的荧光淬灭研究表明,通过疏水相互作用,形成了蛋白质-银复合物,AF4-DAD-FLD-ICP-MS 进一步证实了这一点。从更广泛的角度来看,这项机理研究的结果表明,硅藻通过释放 EPS,可能会极大地影响 EPS 丰富的水生环境中 nAg 的去向,甚至可能影响其生物利用率。
期刊介绍:
Environmental Science: Nano serves as a comprehensive and high-impact peer-reviewed source of information on the design and demonstration of engineered nanomaterials for environment-based applications. It also covers the interactions between engineered, natural, and incidental nanomaterials with biological and environmental systems. This scope includes, but is not limited to, the following topic areas:
Novel nanomaterial-based applications for water, air, soil, food, and energy sustainability
Nanomaterial interactions with biological systems and nanotoxicology
Environmental fate, reactivity, and transformations of nanoscale materials
Nanoscale processes in the environment
Sustainable nanotechnology including rational nanomaterial design, life cycle assessment, risk/benefit analysis