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Particle length-dependent titanium dioxide nanomaterials toxicity and bioactivity.

Authors
Hamilton-RF Jr.; Wu-N; Porter-D; Buford-M; Wolfarth-M; Holian-A
Source
Part Fibre Toxicol 2009 Dec; 6:35
NIOSHTIC No.
20036365
Abstract
Background: Titanium dioxide (TiO2) nanomaterials have considerable beneficial uses as photocatalysts and solar cells. It has been established for many years that pigment-grade TiO2 (200 nm sphere) is relatively inert when internalized into a biological model system (in vivo or in vitro). For this reason, TiO2 nanomaterials are considered an attractive alternative in applications where biological exposures will occur. Unfortunately, metal oxides on the nanoscale (one dimension < 100 nm) may or may not exhibit the same toxic potential as the original material. A further complicating issue is the effect of modifying or engineering of the nanomaterial to be structurally and geometrically different from the original material. Results: TiO2 nanospheres, short (< 5 um) and long (> 15 um) nanobelts were synthesized, characterized and tested for biological activity using primary murine alveolar macrophages and in vivo in mice. This study demonstrates that alteration of anatase TiO2 nanomaterial into a fibre structure of greater than 15 um creates a highly toxic particle and initiates an inflammatory response by alveolar macrophages. These fibre-shaped nanomaterials induced inflammasome activation and release of inflammatory cytokines through a cathepsin B-mediated mechanism. Consequently, long TiO2 nanobelts interact with lung macrophages in a manner very similar to asbestos or silica. Conclusions: These observations suggest that any modification of a nanomaterial, resulting in a wire, fibre, belt or tube, be tested for pathogenic potential. As this study demonstrates, toxicity and pathogenic potential change dramatically as the shape of the material is altered into one that a phagocytic cell has difficulty processing, resulting in lysosomal disruption.
Keywords
Airborne-particles; Alveolar-cells; Biohazards; Biological-effects; Biological-systems; Cell-biology; Cytotoxic-effects; Exposure-assessment; Exposure-levels; Exposure-methods; Fibrous-dusts; Inhalation-studies; Laboratory-animals; Laboratory-testing; Metal-oxides; Microbiology; Microscopic-analysis; Nanotechnology; Particulate-dust; Particulates; Particulate-sampling-methods; Pathogenicity; Phagocytes; Respirable-dust; Respiration; Risk-factors; Statistical-analysis; Toxic-effects; Toxic-materials
Contact
Andrij Holian, Center for Environmental Health Sciences, University of Montana, Missoula, MT
CAS No.
13463-67-7
Publication Date
20091231
Document Type
Journal Article
Email Address
andrij.holian@mso.umt.edu
Fiscal Year
2010
NTIS Accession No.
NTIS Price
ISSN
1743-8977
NIOSH Division
HELD
Priority Area
Manufacturing
Source Name
Particle and Fibre Toxicology
State
MT; WV
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