Lysosomal cytotoxicity of carbon nanoparticles in cells of the molluscan immune system: An in vitro study

The toxicity and ecotoxicity of nanomaterials is poorly understood and the risks of environmental exposure are largely unknown. In vitro cellular toxicity of C60-fullerene and carbon nanotubes was investigated by measuring the retention of a cationic probe (neutral red) within the lysosomal compartment of phagocytic blood cells (hemocytes) from marine mussels (Mytilus galloprovincialis). Intra-lysosomal retention of neutral red, over time, is a measure of the stability of the lysosomal membrane and the health of the cell. Aqueous suspensions of carbon nanoparticles (C60-fullerene – 1.0 and 10 µg.ml−1) induced cytotoxicity in circulating phagocytic hemocytes, which are a key component of the molluscan innate immune system. Hemocytes exposed to the same concentration range of carbon nanotubes were unaffected. These findings are consistent with the hypothesis that C60-fullerene is cytotoxic on uptake into the endocytic-lysosomal system and that cell injury may be mediated by generation of reactive oxygen species (ROS).