Division of Life Science, The Hong Kong University of Science and Technology-HKUST, Clear Water Bay, Kowloon, Hong Kong.
Nanotoxicology. 2012 Jun;6(4):361-70. doi: 10.3109/17435390.2011.579632. Epub 2011 May 18.
Silver nanoparticles (AgNPs) are now widely used in antibacterial and personal care products. However, the underlying physicochemical mechanisms leading to the toxicity of AgNPs are still under debate. The present study revealed the different effects of three surface coatings (including lactate, polyvinylpyrrolidone, and sodium dodecylbenzene sulfonate, as AgNPs-L, AgNPs-P and AgNPs-S, respectively) on the acute toxicity of AgNPs to a model freshwater cladoceran Daphnia magna. Significant difference in mortality was observed among these three surface coatings of AgNPs, with the 48-h 50% lethal concentrations (48-h LC50s) of AgNPs-L, AgNPs-P and AgNPs-S being 28.7, 2.0 and 1.1 μg/L, respectively. In contrast, when the daphnids were exposed to soluble Ag released from AgNPs-L and AgNPs-P, the difference in the 48-h LC50s between the two surface coatings (1.1 μg/L and 0.57 μg/L, respectively) decreased significantly. These 48-h LC50s were comparable to that of AgNO₃ (0.88 μg/L), indicating that soluble Ag was the primarily cause of the observed toxicity of AgNPs. Indeed, the surface coatings influenced the dissolution of AgNPs into soluble Ag, resulting in the different toxicities of AgNP to the daphnids. Additionally, the 48-h bioaccumulation of AgNPs in daphnids was also dependent on the characteristics of the nanoparticles, such as particle size and surface coating. Our results point to the need to consider the effects of surface coating on the toxicity of AgNPs in environmental risk assessments.
纳米银颗粒（AgNPs）现在被广泛应用于抗菌和个人护理产品中。然而，导致 AgNPs 毒性的潜在物理化学机制仍存在争议。本研究揭示了三种表面涂层（包括乳酸盐、聚乙烯吡咯烷酮和十二烷基苯磺酸钠，分别为 AgNPs-L、AgNPs-P 和 AgNPs-S）对模式淡水桡足类动物大型溞急性毒性的不同影响。这三种 AgNPs 的表面涂层在死亡率方面存在显著差异，AgNPs-L、AgNPs-P 和 AgNPs-S 的 48 小时半数致死浓度（48-h LC50）分别为 28.7、2.0 和 1.1μg/L。相比之下，当溞类暴露于从 AgNPs-L 和 AgNPs-P 释放的可溶性 Ag 时，两种表面涂层之间的 48-h LC50 差异（分别为 1.1μg/L 和 0.57μg/L）显著降低。这些 48-h LC50 值与 AgNO₃（0.88μg/L）相当，表明可溶性 Ag 是导致 AgNPs 观察到毒性的主要原因。事实上，表面涂层影响 AgNPs 溶解为可溶性 Ag，从而导致 AgNP 对溞类的不同毒性。此外，AgNPs 在溞类中的 48 小时生物累积也取决于纳米颗粒的特性，如颗粒大小和表面涂层。我们的结果表明，在环境风险评估中需要考虑表面涂层对 AgNPs 毒性的影响。
