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X-ray and electron microscopy studies on the biodistribution and biomodification of iron oxide nanoparticles in Daphnia magna

Title
X-ray and electron microscopy studies on the biodistribution and biomodification of iron oxide nanoparticles in Daphnia magna
Author
윤태현
Keywords
Iron oxide nanoparticles; TEM; STXM; Biodistribution; Biomodification
Issue Date
2014-10
Publisher
Elsevier Science B.V., Amsterdam.
Citation
Colloids and surfaces Biointerfaces , Vol.122 No.- [2014] , 384-389
Abstract
Biodistribution and biomodification of iron oxide (Fe3O4 and α-Fe2O3) nanoparticles (NPs) in a well-known toxicity test organism, Daphnia magna (D. magna), were investigated using transmission electron microscopy (TEM) and scanning transmission X-ray microscopy (STXM). In addition to the morphological changes in the gut tissues of D. magna, biodistribution and biomodification of iron oxide NPs in the digestive tract of D. magna were also monitored in this study. Upon exposures to both iron oxide NPs, unique morphological changes (e.g., irregular shaped microvilli, epithelial cell protrusion, and dilatation of cytoplasmic inclusion) in the gut tissues of D. magna were observed along with bacterial colonization of the gut lumen. However, despite their heavy accumulations in the digesitive tract, TEM and STXM images confirmed us that both Fe3O4 and α-Fe2O3 NPs were not penetrating into the gut tissues of D. magna. Moreover, for the Fe3O4 NPs in direct contact with the gut microvilli of D. magna, slight but significant spectral changes were observed in their Fe L-edge X-ray absorption near edge structure (XANES) spectra, which indicated that there were biomodifications of Fe3O4 NPs, probably involving oxidative dissolution of Fe3O4 NPs followed by rapid precipitation of ferric oxide or hydroxide. However, no significant changes were observed in the Fe L-edge XANES spectra of the α-Fe2O3 NPs present in the gut lumen of D. magna. These X-ray and electron microscopic observations confirmed us that, despite similarities in core sizes and chemical compositions, NPs with different crystalline phase and dissolution rates can interact quite differently with their local environment, may result in different biodistribution and cause completely dissimilar toxicities.
URI
https://www.sciencedirect.com/science/article/pii/S0927776514003786?via%3Dihubhttp://hdl.handle.net/20.500.11754/51147
ISSN
0927-7765; 1873-4367
DOI
10.1016/j.colsurfb.2014.07.016
Appears in Collections:
COLLEGE OF NATURAL SCIENCES[S](자연과학대학) > CHEMISTRY(화학과) > Articles
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