CAS Key Lab for Biomedical Effects of Nanomaterials and Nanosafety, CAS-HKU Joint Laboratory of Metallomics on Health & Environment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
Hebei Provincial Key Lab of Green Chemical Technology & High Efficient Energy Saving, School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, China.
J Nanosci Nanotechnol. 2021 Nov 1;21(11):5436-5442. doi: 10.1166/jnn.2021.19476.
Quantitatively studying the biodistribution and transformation of nanomaterials is of great importance for nanotoxicological evaluation. Recently, laser ablation inductively coupled plasma mass spectrometry has been employed to distinguish nanoparticles (NPs) with their dissolved ions in biological samples. The principle of the proposal is based on a hypothesis that the intact NPs sampled by laser ablation will generate discrete sharp pulses of signals in ICP-MS measurement, being totally different from the continuous, relatively lower signals generated by ions. However, it is still a controversy whether NPs could maintain their intactness during the laser ablation. This work found a way to exactly determine the number of NPs sampled for each LA-ICP-MS measurement. It made possible to reveal the signal profile of a single NP in LA-ICP-MS analysis. The results suggest that AuNR, AgNP and TIO₂ NP were broken into much smaller secondary NPs during the laser ablation, therefore generating continuous signals in the analyzer. There was a certain probability that the fragmentation of large-sized NP or multiple NPs by laser ablation was not sufficient, leaving some NPs unbroken or some secondary NPs with relatively large sizes to generate discrete pulses of signals in the analyzer. When the intactness of NPs during laser ablation cannot be assured, it is impossible to determine the attribution of mass spectrum signals. These findings compromise the reliability of distinguishing NPs from their dissolved ions by LA-ICP-MS.
定量研究纳米材料的体内分布和转化对于纳米毒理学评价非常重要。最近，激光烧蚀电感耦合等离子体质谱法已被用于区分生物样品中的纳米颗粒（NPs）与其溶解离子。该方法的原理基于这样一个假设，即通过激光烧蚀采样的完整 NPs 将在 ICP-MS 测量中产生离散的尖锐信号脉冲，与离子产生的连续、相对较低的信号完全不同。然而，关于 NPs 在激光烧蚀过程中是否能够保持其完整性仍然存在争议。这项工作找到了一种方法，可以准确确定每次 LA-ICP-MS 测量中采样的 NPs 数量。这使得在 LA-ICP-MS 分析中揭示单个 NP 的信号特征成为可能。结果表明，AuNR、AgNP 和 TIO₂ NP 在激光烧蚀过程中被破碎成更小的次级 NPs，因此在分析仪中产生连续的信号。激光烧蚀对大尺寸 NP 或多个 NP 的破碎程度可能不够，导致一些 NP 未破碎或一些次级 NP 尺寸相对较大，从而在分析仪中产生离散的信号脉冲。当不能保证 NPs 在激光烧蚀过程中的完整性时，就不可能确定质谱信号的归属。这些发现影响了通过 LA-ICP-MS 区分 NPs 与其溶解离子的可靠性。
