84 Int. J. Biomedical Nanoscience and Nanotechnology, Vol. 3, Nos. 1/2, 2013 Copyright © 2013 Inderscience Enterprises Ltd. Aggregation behaviour of carbon nanotubes in aqueous and physiological media and its influence on toxicity Susana Addo Ntim Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, USA E-mail: sa57@njit.edu Frank A. Witzmann Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Biotechnology Research and Training Center, Indianapolis, IN 46202, USA E-mail: fwitzman@iupui.edu Somenath Mitra* Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, USA Fax: +01-973-596-3586 E-mail: mitra@njit.edu *Corresponding author Abstract: Extensive use of carbon nanotubes (CNTs) in industry and in the consumer market including drug delivery will increase the likelihood of human exposure and the contamination of the ecosystems. The aggregation state of CNTs has a strong influence on their fate and transport in the environment, as well as their bioavailability. Studies on their colloidal behaviour suggest that they can be relatively stable in aqueous and biological medium, and the presence of surfactants and macromolecules may enhance their dispersibility and persistence. This paper is a review of the aggregation behaviour of CNTs as well as their functional analogues, and the possible role of the dispersal state on toxicity. Keywords: carbon nanotubes; CNTs; dispersion; aggregation; physiological media; water; toxicity. Reference to this paper should be made as follows: Addo Ntim, S., Witzmann, F.A. and Mitra, S. (2013) ‘Aggregation behaviour of carbon nanotubes in aqueous and physiological media and its influence on toxicity’, Int. J. Biomedical Nanoscience and Nanotechnology, Vol. 3, Nos. 1/2, pp.84–106.