Synthesis, characterization and cytotoxicity of phosphoryl choline-grafted water-soluble carbon nanotubes

Carbon nanotubes (CNTs) were rendered water-soluble by grafting on phosphoryl choline (PC). The modified CNTs were characterized utilizing Fourier transform infrared spectra, X-ray photoelectron spectra, thermogravimetric analysis, nuclear magnetic resonance, transmission electron microscopy, ultraviolet/visible absorbance spectra and dynamic laser light-scattering. The results show that the target products are easily dispersed in water and remain dispersed for at least three months. This study showed that both CNTs and CNT-PC induce no cytotoxicity on clonal pheochromocytoma cells (PC12) and human colon carcinoma cell lines (Caco-2). The grafted PC group confers water solubility and keeps the cell-compatibility of CNTs.