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Rod‐shaped iron oxide nanoparticles are more toxic than sphere‐shaped nanoparticles to murine macrophage cells
Author(s) -
Lee Jang Han,
Ju Jae Eun,
Kim Byung Il,
Pak Pyo June,
Choi EunKyung,
Lee HoiSeon,
Chung Namhyun
Publication year - 2014
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.2735
Subject(s) - cytotoxicity , nanoparticle , lactate dehydrogenase , biophysics , chemistry , iron oxide , reactive oxygen species , iron oxide nanoparticles , tumor necrosis factor alpha , particle size , microbiology and biotechnology , biochemistry , in vitro , biology , nanotechnology , materials science , immunology , enzyme , organic chemistry
Variable sizes of nanoparticles, ranging from nano to micro scale, are of toxicological interest. In the present study, the authors hypothesized that, in addition to the size, the shape of iron oxide (Fe 2 O 3 ) nanoparticles is a major factor that contributes to particle cytotoxicity. Cytotoxicity to mouse macrophage cells (RAW 264.7) was investigated using 3 different particles: micro‐sized Fe 2 O 3 (M‐Fe 2 O 3 ), nano‐sized Fe 2 O 3 (N‐Fe 2 O 3 ), and rod‐shaped Fe 2 O 3 (R‐Fe 2 O 3 ). Whereas M‐Fe 2 O 3 and N‐Fe 2 O 3 were located in the vacuole as aggregates, R‐Fe 2 O 3 was often spread throughout the cytoplasm. The extent of cytotoxicity measured by the water soluble tetrazolium (WST‐1) assay was in the order R‐Fe 2 O 3 ≈ N‐Fe 2 O 3 > M‐Fe 2 O 3 , whereas the extent revealed by the lactate dehydrogenase assay was in the order R‐Fe 2 O 3 >> N‐Fe 2 O 3 ≈ M‐Fe 2 O 3 . In addition, the degree of tumor necrosis factor–α and reactive oxygen species (ROS) production was in the order of R‐Fe 2 O 3 > N‐Fe 2 O 3 > M‐Fe 2 O 3 . In addition, a much higher extent of necrosis was associated with the presence of R‐Fe 2 O 3 . These results suggest that the higher degree of necrosis due to R‐Fe 2 O 3 is correlated with both the higher degree of membrane damage and ROS production by R‐Fe 2 O 3 compared with the results of the other Fe 2 O 3 particles. These results also showed that the degree of cytotoxicity of nanoparticles should be evaluated based on shape as well as size, because changes in shape and size are accompanied by alterations in surface area, which relate closely to cytotoxicity. Environ Toxicol Chem 2014;33:2759–2766 . © 2014 SETAC