Surface area of particle administered versus mass in determining the pulmonary toxicity of ultrafine and fine carbon black: comparison to ultrafine titanium dioxide

Sager, Castranova, Castranova Vincent

Description

Nanoparticles are characterized by having a high surface area per mass. Particulate surface area has been reported to play an important role in determining the biological activity of nanoparticles. However, recent reports have questioned this relationship. This study was conducted to determine whether mass of particles or surface area of particles is the more appropriate dose metric for pulmonary toxicity studies. In this study, rats were exposed by intratracheal instillation to various doses of ultrafine and fine carbon black. At 1, 7, or 42 days post-exposure, inflammatory and cytotoxic potential of each particle type was compared on both a mass dosage (mg/rat) as well as an equal surface area dosage (cm 2 of particles per cm 2 of alveolar epithelium). In an additional study, the pulmonary responses to instillation of ultrafine carbon black were compared to equivalent particle surface area doses of ultrafine titanium dioxide. Results Ultrafine carbon black particles caused a dose dependent but transient inflammatory and cytotoxic response. On a mass basis, these responses were significantly (65 fold) greater than those for fine sized carbon black. However, when doses were equalized based on surface area of particles given, the ultrafine carbon black particles were only slightly (non-significantly) more inflammogenic and cytotoxic compared to the fine sized carbon black. At one day post-exposure, inflammatory potencies of the ultrafine carbon black and ultrafine titanium dioxide particles were similar. However, while the pulmonary reaction to ultrafine carbon black resolved with time, the inflammatory effects of ultrafine titanium dioxide were more persistent over a 42 day post-exposure period. Conclusion These results indicate that for low toxicity low solubility materials, surface area of particles administered rather than mass burden of particles may be a more appropriate dose metric for pulmonary toxicity studies. In addition, ultrafine titanium dioxide appears to be more bioactive than ultrafine carbon black on an equivalent surface area of particles delivered basis.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2009
• Nombre de lectures: 6
• Langue: English

Extrait

Pga e 1fo1  ( 2 apegum nr bet nor foaticnoitrup esops)

Particle and Fibre Toxicology Bio Med  Central

Abstract Background: Nanoparticles are characterized by having a high surface area per mass. Particulate surface area has been reported to play an import ant role in determining the biological activity of nanoparticles. However, recent reports have questioned this relationship. This study was conducted to determine whether mass of partic les or surface area of particles is the more appropriate dose metric for pulmonary toxicity st udies. In this study, rats were exposed by intratracheal instillation to various doses of ultrafine and fine carbon bl ack. At 1, 7, or 42 days post- exposure, inflammatory and cytotoxi c potential of each particle type was compared on both a mass dosage (mg/rat) as well as an equal surface area dosage (cm 2 of particles per cm 2 of alveolar epithelium). In an additional study, the pulmonary responses to instillation of ultrafine carbon black were compared to equivalent particle surfac e area doses of ultrafine titanium dioxide. Results: Ultrafine carbon black particles caused a do se dependent but transi ent inflammatory and cytotoxic response. On a mass basis, these response s were significantly (65 fold) greater than those for fine sized carbon black. However, when doses were equalized based on surface area of particles given, the ultrafine carbon black particles were on ly slightly (non-significantly) more inflammogenic and cytotoxic compared to the fi ne sized carbon black. At on e day post-exposure, inflammatory potencies of the ultrafine carbon black and ultr afine titanium dioxide particles were similar. However, while the pulmonary reaction to ul trafine carbon black resolved with time, the inflammatory effects of ultrafin e titanium dioxide were more pe rsistent over a 42 day post- exposure period. Conclusion: These results indicate that for low toxici ty low solubility materi als, surface area of particles administered rather than mass burden of particles may be a more appropriate dose metric for pulmonary toxicity studies. In addition, ultraf ine titanium dioxide appe ars to be more bioactive than ultrafine carbon black on an equivalent surface area of particles delivered basis.

Published: 4 May 2009 Received: 30 September 2008 Particle and Fibre Toxicology 2009, 6 :15 doi:10.1186/1743-8977-6-15  Accepted: 4 May 2009 This article is available from: http://www.pa rticleandfibretoxicology.com/content/6/1/15 © 2009 Sager and Castranova; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons. org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the orig inal work is properly cited.

Address: 1 Health Effects Laboratory Division, Nation al Institute for Occupational Safety and Health, Morgantown, West Virginia, USA and 2 Department of Environmental Health, Harvard Scho ol of Public Health, Boston, Massachusetts, USA Email: Tina M Sager - [e-mail]; Vincent Castranova* - [e-mail] Corresponding author *

Research Open Access Surface area of particle administered versus mass in determining the pulmonary toxicity of ultra fine and fine carbon black: comparison to ultrafine titanium dioxide Tina M Sager 1,2 and Vincent Castranova* 1