Evaluation of cytotoxic responses of raw and functionalized multi-walled carbon nanotubes in human breast cancer (MCF-7) cells

The present investigation was aimed to discover the activity of raw (RCNTs) and functionalized multi-walled carbon nanotubes (FCNTs) for their cytotoxic potential in human breast cancer (MCF-7) cells. The RCNTs were functionalized with the acid treatment method and were characterized by SEM and TEM. The morphology of RCNTs and FCNTs were found to be variable with a size range of ∼10-15 nm diameter were as the length goes up to 2-4 μm. For, cytotoxicity assessments, MCF-7 cells were exposed to RCNTs and FCNTs at 5-400 μg/ml concentrations for 24 h. The cytotoxicity was measured by MTT and NRU assays, and cellular morphology using phase contrast microscope. Further, intracellular reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) were also studied. The results of MTT and NRU assays exhibited a concentration-dependent decrease in cell viability of MCF-7 cells. The RCNTs and FCNTs exposed cells were also found to alter the normal morphology of MCF-7 cells. Furthermore, the cells showed significant induction in ROS generation and reduction in MMP level. The results of this study, demonstrated that RCNTs and FCNTs has the potential to induce cytotoxicity in MCF-7 cells which could be mediated through the reactive oxygen species (ROS) generation.