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 di®erentiated 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¯bers. Initial cell attachment (within seconds) and attachment at 24 h was greater on CNT thread than on the other¯ber types. Stem cells on CNT threads di®erentiated into neurons and astrocytes over several days, on all¯bers. The presence of serum greatly aided the health and spreading of both neurons and astrocytes.

Biomimetic engineered approaches for neural tissue engineering: Spinal cord injury

“…Another advantage of carbon nanomaterials is their high electrical conductivity that positively impacts nerve regeneration. Carbon nanomaterials, for example, demonstrated a better electrophysiological function in neuronal cells 72 ; also, differentiating embryonic stem cells into neurons is possible 73,74 …”

“…Carbon nanomaterials, for example, demonstrated a better electrophysiological function in neuronal cells 72 ; also, differentiating embryonic stem cells into neurons is possible. 73,74 CNTs are composed of graphite, and since this discovery by Iijima, many studies have been focused on the potential of CNTs, like singlewalled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), for disease treatment and tissue engineering. 75 The application of carbon nanotubes for nerve regeneration has become popular.…”

Carbon Nanomaterials: From Therapeutics to Regenerative Medicine

“…Towards this goal, carbon nanomaterials, with or without additional coatings or modifications, have been shown, first in culture systems, to promote and improve neural cell attachment, survival, process outgrowth and function, beginning with pioneering work [33] and then continuing [33][34][35][36][37]. A few key examples are that neural cells grown on carbon nanomaterials exhibit enhanced electrophysiological function [38] and that both embryonic and postnatal stem cells can differentiate into neurons [39][40][41][42]. An exciting recent development in carbon nanomaterial technology has been the production of thread-like materials from the particulate-like carbon nanotubes [43].…”

“…An exciting recent development in carbon nanomaterial technology has been the production of thread-like materials from the particulate-like carbon nanotubes [43]. These promote neurite outgrowth from a variety of neuronal cell types ( Figure 5) [35,42,44,45] and allow neuronal differentiation from postnatal neural stem cells, (Figure 5(C)) [42]. Studies in vivo have begun, focusing on biocompatibility, and are demonstrating promise [46][47][48][49].…”

“…Arrows A point to neurites A) away from the ganglion on the thread and B) extending out of the ganglion (asterisk). C) Mouse CNS neurosphere cells (grown for 5 days in differentiation medium on laminin-coated thread, see(Hopkins et al, 2010) for culture details) differentiated into neurons (green, NST immunostaining) and astrocytes (red, GFAP immunostaining), with blue stained nuclei (DAPI stain)[42].…”