CARBON NANOTUBE RIBBON AND THREAD SUPPORT ATTACHMENT AND DIFFERENTIATION OF NEURAL STEM CELLS

Abstract

Carbon nanotubes (CNTs) have properties that promise an exciting role in nervous tissue repair. CNTs are strong, extremely light weight, biocompatible and electrically conductive. A relatively novel form of CNT material, multiple strands of CNTs spun into thread, accentuates the linear geometry of CNTs while retaining electrical conductivity. We propose that CNT thread, which is strong, pliable and readily manipulated, has the potential to support longitudinal growth of nerves after injury, in nervous system prostheses. Towards understanding how CNT materials support nervous tissue regeneration, we examined the in vitro interactions between CNT materials and neural stem cell-containing neurospheres, prepared from newborn mouse cortices. Intact neurospheres attached to pieces of as-grown arrays of CNTs, CNT "ribbon" material pulled from the arrays, and CNT thread. Stem cells differentiated into both neurons and glia under these conditions. Processes and cells aligned with the longitudinal axis of the CNT materials, both with and without coatings. For comparisons, dissociated neurosphere cells were plated on CNT thread, polypropylene surgical suture thread and commercial carbon fibers. Initial cell attachment (within seconds) and attachment at 24 h was greater on CNT thread than on the other fiber types. Stem cells on CNT threads differentiated into neurons and astrocytes over several days, on all fibers. The presence of serum greatly aided the health and spreading of both neurons and astrocytes. These findings demonstrate that CNT materials, in particular the thread form, are viable preparations for neural cell attachment, outgrowth and differentiation.