The interaction of multi-walled carbon nanotubes (MWNTs) with living unicellular protozoan Stylonychia mytilus was studied. The results indicated that MWNTs were ingested largely by Stylonychia mytilus. Distribution of MWNTs in the cells, redistribution during dividing process of the cells, and excretion from the cells were observed successfully with optical microscope. The dependence of viability of Stylonychia mytilus was determined on the concentration of MWNTs, ranging from 0.1 g/ml to 200 g/ml. It was found that exposure of Stylonychia mytilus to the MWNTs with concentration higher than 1.0 g/ml induced a dose-dependent growth inhibition to the cells and the damage occurred, by fluorescence microscopy, on the macronucleus and external membrane of the cells. The ultrastructure change by electron microscope revealed that the MWNTs exclusively localized to the mitochondria of the cells. It was proposed that the damage of macronucleus, micronucleus, and membrane of the cells, as well as growth inhibition of the cells might be a result of the damage of mitochondria, following this exclusive localization. Our finding provides important information on the bio-security of MWNTs and their migration in aqueous environment.
Journal for Nanoscience and Nanotechnology (JNN) is an international and multidisciplinary peer-reviewed journal with a wide-ranging coverage, consolidating research activities in all areas of nanoscience and nanotechnology into a single and unique reference source. JNN is the first cross-disciplinary journal to publish original full research articles, rapid communications of important new scientific and technological findings, timely state-of-the-art reviews with author's photo and short biography, and current research news encompassing the fundamental and applied research in all disciplines of science, engineering and medicine.