Effect of Functionalized Carbon Nanotubes and their Citric AcidPolymerization on Mesenchymal Stem Cells In Vitro

The effects of acid-functionalized and poly-citric acid (PCA) polymerized carbon nanotubes (CNT) when in contact with mesenchymal stem cells (MSC); a unique genetically unmodified cell line is reported in this work. Treated CNTs lead to different intracellular incorporation, cell proliferation, and cytotoxic and apoptotic behaviors as compared to control samples. Due to the reduced cellular uptake of polymerized CNTs, PCA polymerized CNTs are less cytotoxic and are associated with less apoptotic cell death than the acid-functionalized ones. The effects of nitrogen doped CNTs (CNx) is also reported, showing that un-doped functionalized CNTs present strong stimulation of cell proliferation, whereas CNxs stimulate apoptotic behavior. The study of MSCs in contact with CNTs and PCA is challenging due to the complexity of its various signaling components. Our results provide basis for further study and encourage research towards discovering new cellular responses triggered by these materials.