Biocompatibility of nitrogen-doped multiwalled carbon nanotubes with murine fibroblasts and human hematopoietic stem cells

Chemical vapor deposition (CVD) methods to create carbon nanotubes (CNTs) with specific dopant atoms have been of interest in biomedical applications due to the relative ease of synthesis of doped CNTs with controlled physical properties. However, CNTs generated from CVD are often heterogeneous in chemical functionality, size, aspect ratio, number of walls, and conducting properties resulting in potential inconsistencies during measurement of the physiological activity of cell-CNT interactions. In this work, the biocompatibility of nitrogen-doped multiwalled carbon nanotubes (CNx) with both murine fibroblasts and human hematopoietic stem cells (hHSC) was evaluated. CNx were synthesized by CVD, purified, characterized, and classified into three fractions designated as small-CNx (S-CNx), medium (M-CNx), and large (L-CNx). Mammalian cells were incubated with CNx doses between 0.07 and 70 μg/mL, and cell viability was evaluated. hHSC and murine fibroblast both demonstrated non-significant differences in proliferation rates when exposed to M-CN, whereas, either cells experienced inhibited growth following exposure to either S-CNx and L-CNx under the same conditions. In this work, it has been demonstrated that CNTs produced by CVD have differences on the biocompatibility with mammalian cells, but the M-CNx could be a great candidate for biomedical applications.