Dispersion Method for Safety Research on Manufactured          Nanomaterials

Wenting WU; Gaku ICHIHARA; Yuka SUZUKI; Kiyora IZUOKA; Saeko OIKAWA-TADA; Jie CHANG; Kiyoshi SAKAI; Kunichi MIYAZAWA; Dale PORTER; Vincent CASTRANOVA; Masami KAWAGUCHI; Sahoko ICHIHARA

doi:10.2486/indhealth.2012-0218

Original Articles

Dispersion Method for Safety Research on Manufactured Nanomaterials

Wenting WU, Gaku ICHIHARA, Yuka SUZUKI, Kiyora IZUOKA, Saeko OIKAWA-TADA, Jie CHANG, Kiyoshi SAKAI, Kunichi MIYAZAWA, Dale PORTER, Vincent CASTRANOVA, Masami KAWAGUCHI, Sahoko ICHIHARA

Author information

Wenting WU
Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Japan
Graduate School of Regional Innovation Studies, Mie University, Japan
Gaku ICHIHARA
Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Japan
Yuka SUZUKI
Graduate School of Regional Innovation Studies, Mie University, Japan
Kiyora IZUOKA
Graduate School of Regional Innovation Studies, Mie University, Japan
Saeko OIKAWA-TADA
Graduate School of Regional Innovation Studies, Mie University, Japan
Jie CHANG
Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Japan
Graduate School of Regional Innovation Studies, Mie University, Japan
Kiyoshi SAKAI
Nagoya City Public Health Research Institute, Japan
Kunichi MIYAZAWA
National Institute for Materials Science, Japan
Dale PORTER
National Institute for Occupational Safety and Health, USA
Vincent CASTRANOVA
National Institute for Occupational Safety and Health, USA
Masami KAWAGUCHI
Division of Chemistry for Materials, Graduate School of Engineering, Mie University, Japan
Sahoko ICHIHARA
Graduate School of Regional Innovation Studies, Mie University, Japan

Keywords: Nanomaterials, Nanoparticles, Carbon nanotubes, Safety research, Suspension, Dispersion, Sonication

JOURNAL FREE ACCESS FULL-TEXT HTML

2014 Volume 52 Issue 1 Pages 54-65

DOI https://doi.org/10.2486/indhealth.2012-0218

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Abstract

Nanomaterials tend to agglomerate in aqueous media, resulting in inaccurate safety assessment of the biological response to these substances. The present study searched for suitable dispersion methods for the preparation of nanomaterial suspensions. Titanium dioxide (TiO₂) and zinc oxide (ZnO) nanoparticles were dispersed in a biocompatible dispersion medium by direct probe-type sonicator and indirect cup-type sonicator. Size characterization was completed using dynamic light scattering and transmission electron microscopy. A series of dispersion time and output power, as well as two different particle concentrations were tested. Microscopic contamination of metal titanium that broke away from the tip of the probe into the suspension was found. Size of agglomerated nanoparticles decreased with increase in sonication time or output power. Particle concentration did not show obvious effect on size distribution of TiO₂ nanoparticles, while significant reduction of secondary diameter of ZnO was observed at higher concentration. A practicable protocol was then adopted and sizes of well-dispersed nanoparticles increased by less than 10% at 7 d after sonication. Multi-walled carbon nanotubes were also well dispersed by the same protocol. The cup-type sonicator might be a useful alternative to the traditional bath-type sonicator or probe-type sonicator based on its effective energy delivery and assurance of suspension purity.

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