Title: Stable silver isotope fractionation in the natural transformation process of silver nanoparticles

Author: Dawei Lu, Qian Liu*, Tuoya Zhang, Yong Cai, Yongguang Yin and Guibin Jiang*

Abstract: Nanoparticles in the environment can form by natural processes or be released due to human activities. Owing to limited analytical methods, the behaviour of nanoparticles in the natural environment is poorly understood and until now they have only been described by the variations in the nanoparticle size or the concentration of the element of interest. Here we show that by using inductively coupled plasma mass spectrometry to measure silver (Ag) isotope ratios it is possible to understand the transformation processes of silver nanoparticles (AgNPs) in the environment. We found that the formation and dissolution of AgNPs under natural conditions caused significant variations in the ratio of natural Ag isotopes (107Ag and 109Ag) with an isotopic enrichment factor (ε) up to 0.86‰. Furthermore, we show that engineered AgNPs have distinctly different isotope fractionation effects to their naturally formed counterparts. Further studies will be needed to understand whether isotope analysis can be used to reveal the sources of AgNPs in the environment.

Link: http://dx.doi.org/10.1038/nnano.2016.93

Comment: 这是我们在非传统稳定同位素方面的第一个工作，原创的想法，所有实验均在本课题组完成，最终能够发表在Nature Nanotech，历经波折和磨难。idea大概在2012年就有了，从建立分析方法到确定最终实验体系，随着实验的进行对体系的理解也在不断加深，于是不断地修正实验设计和目标，不断地补充实验和修改论文，历经了两年左右终于成稿。

投稿过程也是异常艰辛，投到Nature Nanotech后总审稿时长达到了13个月，历经4轮修改方被接受。在此不得不感谢Nature Nanotech的审稿人和编辑，这种high-profile journal和其他杂志是完全不同，审稿人非常非常专业，有一位审稿人在头两轮中都给出比论文长度还要长一倍的审稿意见，而且事无巨细地指出文章存在的所有问题，任何心怀侥幸的软伤硬伤在审稿人面前最终一个都没有逃脱，论文修改过程就像是重新上了一门专业前沿课，受益巨大。虽然严厉，但审稿人自始至终都不吝对我们的工作的意义给予最高的褒奖，认为是“一项开创性的里程碑式的工作——a pioneering landmark study”，感觉他们就像对待自己的学生一样，一轮一轮地让这篇论文趋向完美。我觉得非常幸运能够碰到这样的审稿人，在文章的acknowledgement里面也进行了专门的致谢。编辑对论文的理解也非常深刻，值得一提的是，最终的Abstract是编辑根据自己对文章的理解，按照杂志的house style重新撰写的，功力之深可见一斑。

令人兴奋的是，论文在线发表后，Nature Nanotech同时以“Nanoecotoxicology: Nanoparticle behaviour dissected”为题专门配发了两页篇幅的news and views评论文章，对该工作的背景和科学意义进行了详细解读，认为“这一发现具有相当的重要性——the importance of the findings reported is substantial”，“这一开创性的工作证明了纳米材料的同位素分馏值得深入研究——the pioneering work of Liu and colleagues has demonstrated that this is an issue worth looking at”。这对我们继续深入开展这方面的工作是一个巨大的鼓舞。

全文链接：http://dx.doi.org/10.1038/nnano.2016.93

news and views链接：http://dx.doi.org/10.1038/nnano.2016.119

欢迎大家批评指正！