Bouldin Jennifer L, Ingle Taylor M, Sengupta Anindita, Alexander Regina, Hannigan Robyn E, Buchanan Roger A
Environmental Sciences Program, Arkansas State University, Jonesboro, Arkansas 72467, USA.
Environ Toxicol Chem. 2008 Sep;27(9):1958-63. doi: 10.1897/07-637.1.
Innovative research and diagnostic techniques for biological testing have advanced during recent years because of the development of semiconductor nanocrystals. Although these commercially available, fluorescent nanocrystals have a protective organic coating, the inner core contains cadmium and selenium. Because these metals have the potential for detrimental environmental effects, concerns have been raised over our lack of understanding about the environmental fate of these products. U.S. Environmental Protection Agency test protocol and fluorescence microscopy were used to determine the fate and effect of quantum dots (QDs; Qdot 545 ITK Carboxyl Quantum Dots [Fisher Scientific, Fisher part Q21391MP; Invitrogen Molecular Probes, Eugene, OR, USA]) using standard aquatic test organisms. No lethality was measured following 48-h exposure of Ceriodaphnia dubia to QD suspensions as high as 110 ppb, but the 96-h median lethal concentration to Pseudokirchneriella subcapitata was measured at 37.1 ppb. Transfer of QDs from dosed algae to C. dubia was verified with fluorescence microscopy. These results indicate that coatings present on nanocrystals provide protection from metal toxicity during laboratory exposures but that the transfer of core metals from intact nanocrystals may occur at levels well above toxic threshold values, indicating the potential exposure of higher trophic levels. Studies regarding the fate and effects of nanoparticles can be incorporated into models for predictive toxicology of these emerging contaminants.
近年来，由于半导体纳米晶体的发展，用于生物测试的创新研究和诊断技术取得了进展。尽管这些市售的荧光纳米晶体有一层保护性有机涂层，但其内核含有镉和硒。由于这些金属可能对环境产生有害影响，人们对我们对这些产品的环境归宿缺乏了解表示担忧。美国环境保护局的测试方案和荧光显微镜被用于使用标准水生测试生物来确定量子点（QDs；Qdot 545 ITK羧基量子点[Fisher Scientific，Fisher部件Q21391MP；Invitrogen Molecular Probes，美国俄勒冈州尤金市]）的归宿和影响。将大型溞暴露于高达110 ppb的量子点悬浮液48小时后，未测得致死率，但测得对斜生栅藻的96小时半数致死浓度为37.1 ppb。通过荧光显微镜证实了量子点从投喂的藻类转移到大型溞。这些结果表明，纳米晶体上的涂层在实验室暴露期间提供了免受金属毒性的保护，但完整纳米晶体中核心金属的转移可能在远高于毒性阈值的水平发生，这表明更高营养级可能受到暴露。关于纳米颗粒归宿和影响的研究可以纳入这些新兴污染物的预测毒理学模型。
