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Use of carbon nanotubes for novel approaches towards spinal network repairing
Turco, Antonio
2013-04-23
Abstract
Nanotechnology underwent a very rapid development in the last decades, thanks
to the invention of different techniques that allow reaching the nanoscale. The
great interest in this area arises from the variety of possible applications in
different fields, such as electronics, where the miniaturization of components is
a key factor, but also medicine. The creation of smart systems able to carry out a
specific task in the body in a controlled way, either in diagnosis or therapy or
tissue engineering, is the ultimate goal of a newborn area of research, called
nanomedicine. In fact, to reach such an outstanding objective, a nanometer‐sized
material is needed and carbon nanotubes (CNTs) are among the most promising
candidates. The aim of this thesis was to study this opportunity and, in particular,
the possible application of carbon nanotubes for spinal network repairing.
After a review of the main features of neuronal network systems and the
most common techniques to study their functionality, possible
applications of nanotechnology for nanomedicine purposes are
considered, focusing the attention on CNTs as neuronal interface in nerve
tissue engineering.
The work can be divided into two big parts. In the first part the impact of carbon
nanotubes on various neuronal systems was studied. Different form of
carbonaceous materials (carbon nanotubes, nanohorns and graphene) were
deposited in a homogeneous way on a glass surface playing with organic
functionalization and different deposition techniques. Hippocampal neuronal
cells were grown on their surface to better understand how morphology and
conductivity of the material could influence the activity of the neuronal network
evidencing how both these characteristics could affect the electrophysiological
properties of neurons. Then, also spinal neurons were grown on carbon nanotubes
network deposited on a glass substrate to evaluate, for the first time, the impact
of carbon nanotubes on this kind of cells. The tight interaction between these two
materials appeared to cause a faster maturation of the spinal neurons with respect
II
to the control grown on a glass substrate. The long-term impact on a complex
tissue (spinal cord slice) grown on carbon nanotubes carpet was also studied. The
intimate interaction between the two materials observed by TEM and SEM
analysis caused an increase in dimensions and number of neuronal fibers that
comes out from the body of a spinal cord slice. An increase in
electrophysiological activity of all neuronal network of the slice was also
reported.
In the second part of the work different conductive biocompatible nanocomposite
materials based on carbon nanotubes and “artificial” polymers (such as Nafion,
PVA, PET, PEI, PDMS and PANI) were investigated. The idea is to test these
materials as neuronal prosthesis to repair spinal cord damage. All the prepared
scaffolds showed CNTs on the surface favoring CNTs-neurons interaction. To
address this aim different techniques and different organic functionalizations of
CNTs were utilized to control supramolecular interactions between the
nanomaterial and polymers orienting the deposition of the CNTs and preventing
their aggregation. After that, an innovative method to study the possible ability
of this nanocomposite materials to transmit a neuronal signal between two
portions of spinal cord was designed.
Functionalization of gold surfaces with thiolated carbon nanotubes have been
conducted in order to develop suitable devices for neuronal stimulation and
consequent spinal cord lesions repairing. In particular thiol groups were
introduced on the graphitic surface of carbon nanotubes by means of covalent
functionalization. First of all, the interaction of CNTs with gold nanoparticles has
been evaluated, then a gold surface has been coated by means of contact printing
technique with a homogeneous film of CNTs. This hybrid material could be
useful to produce innovative electrodes for neuronal stimulation
Publisher
Università degli studi di Trieste
Languages
en
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