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Influence of acid functionalization on the cardio-pulmonary toxicity of carbon nanotubes and carbon black in mice
Citation:
TONG, H., J. K. MCGEE, K. Rajiv, P. Urmila, U. P. KODAVANTI, R. B. DEVLIN, AND M. I. GILMOUR. Influence of acid functionalization on the cardio-pulmonary toxicity of carbon nanotubes and carbon black in mice. TOXICOLOGY AND APPLIED PHARMACOLOGY. Academic Press Incorporated, Orlando, FL, 239(3):224-232, (2009).
Impact/Purpose:
research results
Description:
Engineered carbon nanotubes are being developed for a wide range of industrial and medical applications. Because of their unique properties, nanotubes can impose potentially toxic effects, particularly if they have been modified to express functionally reactive chemical groups on their surface. The present study was designed to evaluate whether acid functionalization (AF) enhanced the cardiopulmonary toxicity of single-walled carbon nanotubes (SWCNT) as well as control carbon black particles. Mice were exposed by oropharyngeal aspiration to 10 or 40 g of saline-suspended single-walled carbon nanotubes (SWCNTs), acid-functionalized SWCNTs (AF-SWCNTs), ultrafine carbon black (UFCB), AF-UFCB, or 2 g LPS. Twenty-four hours later, pulmonary inflammatory responses and cardiac function were assessed by bronchoalveolar lavage and cardiac perfusion respectively, and compared to saline or LPS-instilled animals. Instillation of 10 g of SWCNTs or UFCB did not cause significant inflammation, however, 40 g of SWCNTs or UFCB increased pulmonary neutrophil numbers and this response was enhanced if the particles were acid-functionalized. Perfused hearts from mice exposed to 40 g of AF-SWCNTs had significantly lower cardiac functional recovery, greater infarct size, and higher coronary flow rate than those of saline and SWCNT-exposed animals. In contrast, hearts from mice exposed to 10 g of AF-SWCNTs, SWCNTs, UFCB, AF-UFCB and LPS had no significant changes in cardiac ischemia/reperfusion injury. Furthermore, hearts from mice exposed to 40 g of AF-SWCNT exhibited signs of focal cardiac myofiber degeneration compared to controls. This study indicates that while acid functionalization increases the pulmonary toxicity of both UFCB and SWCNTs, this treatment caused cardiac effects with only the carbon nanotubes. Further experiments are needed to understand the physicochemical processes involved in this phenomenon. Key words: Acid functionalization, SWCNT, carbon black, cardiopulmonary toxicity
