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Int. J. Mol. Sci. 2017, 18(12), 2757;

Biopersistence of NiO and TiO2 Nanoparticles Following Intratracheal Instillation and Inhalation

Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahata-nishi-ku, Kitakyushu, Fukuoka 807-8555, Japan
Department of Chemical Engineering, Hiroshima University, Higashi-Hiroshima 739-8528, Japan
National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
Author to whom correspondence should be addressed.
Received: 1 December 2017 / Revised: 15 December 2017 / Accepted: 15 December 2017 / Published: 19 December 2017
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The hazards of various types of nanoparticles with high functionality have not been fully assessed. We investigated the usefulness of biopersistence as a hazard indicator of nanoparticles by performing inhalation and intratracheal instillation studies and comparing the biopersistence of two nanoparticles with different toxicities: NiO and TiO2 nanoparticles with high and low toxicity among nanoparticles, respectively. In the 4-week inhalation studies, the average exposure concentrations were 0.32 and 1.65 mg/m3 for NiO, and 0.50 and 1.84 mg/m3 for TiO2. In the instillation studies, 0.2 and 1.0 mg of NiO nanoparticles and 0.2, 0.36, and 1.0 mg of TiO2 were dispersed in 0.4 mL water and instilled to rats. After the exposure, the lung burden in each of five rats was determined by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES) from 3 days to 3 months for inhalation studies and to 6 months for instillation studies. In both the inhalation and instillation studies, NiO nanoparticles persisted for longer in the lung compared with TiO2 nanoparticles, and the calculated biological half times (BHTs) of the NiO nanoparticles was longer than that of the TiO2 nanoparticles. Biopersistence also correlated with histopathological changes, inflammatory response, and other biomarkers in bronchoalveolar lavage fluid (BALF) after the exposure to nanoparticles. These results suggested that the biopersistence is a good indicator of the hazards of nanoparticles. View Full-Text
Keywords: NiO; TiO2; nanoparticles; biopersistence; lung burden; inhalation; intratracheal instillation NiO; TiO2; nanoparticles; biopersistence; lung burden; inhalation; intratracheal instillation

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Oyabu, T.; Myojo, T.; Lee, B.-W.; Okada, T.; Izumi, H.; Yoshiura, Y.; Tomonaga, T.; Li, Y.-S.; Kawai, K.; Shimada, M.; Kubo, M.; Yamamoto, K.; Kawaguchi, K.; Sasaki, T.; Morimoto, Y. Biopersistence of NiO and TiO2 Nanoparticles Following Intratracheal Instillation and Inhalation. Int. J. Mol. Sci. 2017, 18, 2757.

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