| Popis: |
Ceria nanoparticles (NPs), due to their widespread applications, have attracted a lot of concern about their toxic effects on both human health and environment. Cerium occurs in two oxidation states, Ce (III) and Ce (IV), and has the unique ability to readily switch between these two states. There is a lot of speculation on the redox behaviour of cerium oxide being related to its toxicity but there are large gaps in knowledge of whether Ce (III) or Ce (IV) is responsible for such toxic behaviours, their toxicological mechanism and safety assessment. The aim of this study is to accurately quantify the ratio of Ce (III) and Ce (IV) in synthesised ceria samples using a multi-method approach thus providing an insight in understanding their surface chemistry and hence biological behaviour. Ceria NPs of different shapes and sizes were produced with different strengths of interaction between core and capping agent/no capping agent and with both steric and charge stabilization. The oxidation state of the samples was determined using STEM-EELS and XPS. Later in the study, we investigated the uptake and internalisation of different shapes and sizes of ceria NPs in lung-derived A549 cell lines (Adenocarcinomic human alveolar basal epithelial cells, A549). |
