Multi-walled Carbon Nanotubes Affect the Morphology and Membrane Potential of Mitochondria in HeLa Cell

Carbon nanotubes (CNTs) have unique physical features with high strength, and they could be first used as field-emission electron sources (Deheer & Ugarte, 1995), which could be applied to transistors (Bachtold et al., 2001). With these and related characteristics, the use of CNTs is rapidly increasing in wide variety of fields, such as clothes’ fibers, unique materials for extreme conditions, and parts of nano-machines. However, the safety of CNT’s is one of the important and emerging concerns. Several researches have shown that a specific type and concentrations of CNT’s are toxic to mammalian cells (Jia et al., 2005; Monteiro-Riviere et al., 2005; Muller et al., 2005; Kostarelos, 2008; Firme & Bandaru, 2010). For example, high concentration of multi-walled carbon nanotubes (MWNT) induced apoptosis of T lymphocyte (Bottini et al., 2006). Although relatively low concentration of MWNT, and CNTs in general, is believed to be safe, duration of the CNT exposure, and the cellular accumulation of these synthetic materials are yet to be explored. In addition, development of more sensitive tools to assess cellular quality after CNTs is desirable. Mitochondria are one of the most essential organelles for the life of cells. They produce adenosine triphosphate (ATP) during the electron chain transfer cycles occurring in the inner mitochondrial membrane. For the ATP production, mitochondrial membrane potentials are required. Morphologically, mitochondria are highly dynamic in cells, and continuously fuse and divide (Kane & Youle, 2010; Galloway et al., 2012; Kim et al., 2013; Hoppins, 2014). More recently, it has been demonstrated that mitochondrial function/membrane potential is closely associated with mitochondrial morphology (Galloway et al., 2012; Liesa & Shirihai, 2013; Liu et al., 2014). In fact, many cell proliferation/ Multi-walled Carbon Nanotubes Affect the Morphology and Membrane Potential of Mitochondria in HeLa Cell