Huang Yingyan, Lum Judy Tsz-Shan, Leung Kelvin Sze-Yin
Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region, People's Republic of China.
HKBU Institute of Research and Continuing Education, Shenzhen Virtual University Park, Shenzhen, People's Republic of China.
Anal Bioanal Chem. 2022 May;414(11):3397-3410. doi: 10.1007/s00216-022-03958-z. Epub 2022 Feb 7.
Cerium dioxide nanoparticles (CeO NPs) are widely used in various fields, leading to concern about their effect on human health. When conducting in vivo investigations of CeO NPs, the challenge is to fractionate ionic Ce and CeO NPs and to characterize CeO NPs without changing their properties/state. To meet this challenge, we developed an integrated inductively coupled plasma-mass spectrometry (ICP-MS)-based analytical approach in which ultrafiltration is used to fractionate ionic and nanoparticulate Ce species while CeO NPs are characterized by single particle-ICP-MS (sp-ICP-MS). We used this technique to compare the effects of two sample pretreatment methods, alkaline and enzymatic pretreatments, on ionic Ce and CeO NPs. Results showed that enzymatic pretreatment was more efficient in extracting ionic Ce or CeO NPs from animal tissues. Moreover, results further showed that the properties/states of all ionic and nanoparticulate Ce species were well preserved. The rates of recovery of both species were over 85%; the size distribution of CeO NPs was comparable to that of original NPs. We then applied this analytical approach, including the enzymatic pretreatment and ICP-MS-based analytical techniques, to investigate the bioaccumulation and biotransformation of CeO NPs in mice. It was found that the thymus acts as a "holding station" in CeO NP translocation in vivo. CeO NP biotransformation was reported to be organ-specific. This is the first study to evaluate the impact of enzymatic and alkaline pretreatment on Ce species, namely ionic Ce and CeO NPs. This integrated ICP-MS-based analytical approach enables us to conduct in vivo biotransformation investigations of CeO NPs.
二氧化铈纳米颗粒（CeO NPs）在各个领域广泛应用，这引发了人们对其对人类健康影响的关注。在对CeO NPs进行体内研究时，面临的挑战是分离离子态铈和CeO NPs，并在不改变其性质/状态的情况下对CeO NPs进行表征。为应对这一挑战，我们开发了一种基于电感耦合等离子体质谱（ICP-MS）的综合分析方法，其中超滤用于分离离子态和纳米颗粒态的铈物种，而CeO NPs则通过单颗粒ICP-MS（sp-ICP-MS）进行表征。我们使用该技术比较了两种样品预处理方法，即碱性预处理和酶预处理，对离子态铈和CeO NPs的影响。结果表明，酶预处理在从动物组织中提取离子态铈或CeO NPs方面更有效。此外，结果还进一步表明，所有离子态和纳米颗粒态铈物种的性质/状态都得到了很好的保留。两种物种的回收率均超过85%；CeO NPs的尺寸分布与原始纳米颗粒相当。然后，我们应用这种分析方法，包括酶预处理和基于ICP-MS的分析技术，来研究CeO NPs在小鼠体内的生物积累和生物转化。研究发现，胸腺在CeO NPs体内转运过程中起到“中转站”的作用。据报道，CeO NPs的生物转化具有器官特异性。这是第一项评估酶预处理和碱性预处理对铈物种（即离子态铈和CeO NPs）影响的研究。这种基于ICP-MS的综合分析方法使我们能够对CeO NPs进行体内生物转化研究。
