Wang Songshan, Lv Jitao, Ma Jingyuan, Zhang Shuzhen
a State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing , P.R. China and.
b Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai , P.R. China.
Nanotoxicology. 2016 Oct;10(8):1129-35. doi: 10.1080/17435390.2016.1179809. Epub 2016 May 16.
It is necessary to elucidate cellular internalization and intracellular biotransformation in order to accurately assess the toxicity and fate of nanoparticles after interaction with organisms. Therefore, this work employed a combination of high resolution imaging and in situ detection spectroscopic techniques to systematically investigate the intracellular localization, morphology and chemical speciation of silver in the cells of Chlamydomonas reinhardtii, a unicellular freshwater green alga, after exposure to AgNPs coated with polyvinylpyrrolidone at a concentration of 2.0 mg/L. High resolution secondary ion mass spectrometry and high-angle annular dark field scanning transmission electron microscopy together with energy dispersive spectroscopy and selected area electron diffraction collectively confirmed that after 48 h of exposure, AgNPs entered the periplasmic space after cellular internalization into the algal cells. Silver was also found to coexist with sulfur inside the cytoplasm in both crystalline and amorphous forms, which were further identified as β-Ag2S and silver thiolates with synchrotron X-ray absorption spectroscopy. In combination, these analyses demonstrated that silver inside algae could be attributed to the uptake and sequestration of Ag(+) ion released from AgNPs, which was further sequestrated into cellular compartments. This study provides solid evidence for particle internalization and biotransformation of AgNPs after interaction with algae.
为了准确评估纳米颗粒与生物体相互作用后的毒性和归宿，有必要阐明细胞内化和细胞内生物转化过程。因此，本研究采用高分辨率成像和原位检测光谱技术相结合的方法，系统地研究了单细胞淡水绿藻莱茵衣藻细胞在暴露于浓度为2.0 mg/L的聚乙烯吡咯烷酮包覆的AgNPs后，细胞内银的定位、形态和化学形态。高分辨率二次离子质谱、高角度环形暗场扫描透射电子显微镜以及能量色散光谱和选区电子衍射共同证实，暴露48小时后，AgNPs在细胞内化进入藻类细胞后进入周质空间。同步辐射X射线吸收光谱进一步鉴定出，在细胞质内，银还以晶体和非晶态形式与硫共存，分别为β-Ag2S和硫醇银。综合这些分析表明，藻类细胞内的银可归因于从AgNPs释放的Ag(+)离子的摄取和螯合，这些离子进一步被螯合到细胞区室中。本研究为AgNPs与藻类相互作用后的颗粒内化和生物转化提供了确凿证据。
