BIOMEDICAL APPLICATIONS VI: CARBON NANOTUBES AS BIOSENSING AND BIO-INTERFACIAL MATERIALS - Carbon Nanotubes: From Bench Chemistry to Promising Biomedical Applications - page 208

7.3.2.2 Applicaons for neural ssue engineering

As strong, lexible and conductive materials, CNTs were explored for their
potential for neural tissue engineering. Mattson et al. 108 applied CNTs for neural
cell culture. The embryonic rat-brain neurons were cultured on unmodiied
CNTs and CNTs coated with bioactive 4-hydroxynonenal elaborate multiple
neuritis. In unmodiied CNTs, the growth of neurons was limited to only one
or two neurite extensions. However functionalized CNTs are good candidates
and enable extensive branching of neural cells..
Gheith's group 109 demonstrated that SWNT layer-by-layer ilm could
support the growth, viability and differentiation of neuronal NG108-15
neuroblastoma/glioma hybrid cells. Furthermore, the electrical conductivity
of the SWNTs made the layer-by-layer ilm substrate, which could transfer
electric signals to the neural cell NG108-15. 110 Those results indicated CNTs
as novel biomaterials for neuron tissue.
Gabay and coworkers 111 established a method for the self-organisation of
neural networks on CNTs. CNT islands on SiO 2 were used as template. Cells
proliferated on the CNT clusters and formed connections between the islands.
The cells were active in generating action potential with normal shapes in
response to electrical stimulation, demonstrating that the CNT template did
not change the functionality of the neurons. The growth of neurons could
be directed by various patterned CNTs and for 2D neural networks. Zhang
and collaborators 112 prepared different CNT templates, including lines and
circles. The growth of neurite cells was observed to be restricted along the
sidewalls of the MWNTs.
Hu et al. 113 studied the effect from the charge of functionalised CNTs on
the morphology of neuron cells. A positive charge resulted in longer-than-
average length of neuritis and more branches of neurites, suggesting the
possibility of controlling the cell outgrowth by chemical modiication.
Further information can be found in the chapter dedicated to CNTs for
neuronal living networks (Chapter 6).

7.3.2.3 Applicaon for other cells and ssues engineering

Besides bone cells and neural cells, many kinds of other cells were also found
to be compatible with CNTs.
Ago and coworkers 114 developed a simple but effective method to
immobilize Hela cells on a CNT array. Hela cells were centrifuged under
100-200 g for 5 minutes in a centrifuge tube containing aligned nanotubes
covering a Si substrate. The cells were then pressed onto the nanotube array.