Anisotropic Membrane Diffusion of Human Mesenchymal Stem Cells on Aligned Single-Walled Carbon Nanotube Networks

The diffusion of lipids and proteins in cell membranes is involved in various cellular processes such as cell adhesion and cellular signaling. We report the anisotropic molecular diffusion in the membranes of human mesenchymal stem cells on aligned single-walled carbon nanotube networks. In this study, the cells were first cultured on the surfaces of glass, graphene, and carbon nanotube networks with random or aligned orientations. Then, the molecular diffusion constants of the cell membranes were measured using a fluorescence-recovery-after-photobleaching technique. The cells on graphene exhibited a diffusion constant comparable to that on glass substrate, while those on the rough surface of randomly oriented carbon nanotube networks exhibited a rather low diffusion constant. On the aligned carbon nanotube networks, the molecules in the cell membrane were found to diffuse faster along the direction parallel to the aligned carbon nanotubes than along the direction orthogonal to the nanotubes. These results indicate that the nanoscale properties of nanostructured materials may significantly affect the molecular diffusion in cell membranes and, possibly, related cellular processes.