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Dispersion method for safety research on manufactured nanomaterials.

Wu W, Ichihara G, Suzuki Y, Izuoka K, Oikawa-Tada S, Chang J, Sakai K, Miyazawa K, Porter D, Castranova V, Kawaguchi M, Ichihara S - Ind Health (2013)

Bottom Line: Nanomaterials tend to agglomerate in aqueous media, resulting in inaccurate safety assessment of the biological response to these substances.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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Japan.

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.

Show MeSH
Optical microscope micrographs of MWCNT suspensions at concentration of 2.0 mg/ml:(a) un-dispersed, (b) dispersed by a cup-type sonicator at 100 W, 80% pulse mode,for 10 min, and (c) for another 10 min; and (d) TEM micrograph of MWCNT sonicatedtwice.
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fig_008: Optical microscope micrographs of MWCNT suspensions at concentration of 2.0 mg/ml:(a) un-dispersed, (b) dispersed by a cup-type sonicator at 100 W, 80% pulse mode,for 10 min, and (c) for another 10 min; and (d) TEM micrograph of MWCNT sonicatedtwice.

Mentions: Dispersion of suspensions of MWCNTs at a concentration of 2.0 mg/ml was operated usingthe protocol: cup-type sonicator at 100 W, 80% pulse mode, for 10 min. The dispersionstatus was assessed using optical microscopy and TEM. Highly agglomerated masses ofMWCNTs were dispersed into smaller size clusters after a single dispersion process(Fig. 8 (a) and (b)Fig. 8.


Dispersion method for safety research on manufactured nanomaterials.

Wu W, Ichihara G, Suzuki Y, Izuoka K, Oikawa-Tada S, Chang J, Sakai K, Miyazawa K, Porter D, Castranova V, Kawaguchi M, Ichihara S - Ind Health (2013)

Optical microscope micrographs of MWCNT suspensions at concentration of 2.0 mg/ml:(a) un-dispersed, (b) dispersed by a cup-type sonicator at 100 W, 80% pulse mode,for 10 min, and (c) for another 10 min; and (d) TEM micrograph of MWCNT sonicatedtwice.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4202770&req=5

fig_008: Optical microscope micrographs of MWCNT suspensions at concentration of 2.0 mg/ml:(a) un-dispersed, (b) dispersed by a cup-type sonicator at 100 W, 80% pulse mode,for 10 min, and (c) for another 10 min; and (d) TEM micrograph of MWCNT sonicatedtwice.
Mentions: Dispersion of suspensions of MWCNTs at a concentration of 2.0 mg/ml was operated usingthe protocol: cup-type sonicator at 100 W, 80% pulse mode, for 10 min. The dispersionstatus was assessed using optical microscopy and TEM. Highly agglomerated masses ofMWCNTs were dispersed into smaller size clusters after a single dispersion process(Fig. 8 (a) and (b)Fig. 8.

Bottom Line: Nanomaterials tend to agglomerate in aqueous media, resulting in inaccurate safety assessment of the biological response to these substances.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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Japan.

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.

Show MeSH