Biomedical Engineering Reference
In-Depth Information
1.4 Control of Neural Stem Cell Behaviour by
Hyaluronic Acid Hydrogel
NSC are a kind of adult stem cells, and they possess the ability to
differentiate into the major cell types in the nervous system, including
neurons, astrocytes and oligodendrocytes, so they can potentially
regenerate after nervous system injury [4]. Injured neurons have an
extremely limited capacity for self renewal, so implanted NSC can
be used to substitute for these, after any damage in the CNS [3].
The NSC reside in some parts of the foetal and adult CNS where
neurogenesis is relatively active. In these areas the behaviour and
fate of NSC are critically guided by certain factors. These factors,
which may be lost after CNS injury, can be reintroduced by HA
hydrogel scaffolds as mentioned above. Therefore, the HA hydrogel
can profoundly impact on the functions of either endogenous or
exogenous NSC, including their adhesion, migration, proliferation
and differentiation, and importantly, they can help in the harvesting
of neurons.
1.4.1 Cell Adhesion
In the native tissue, the HA scaffold has many potential binding
partners for further ECM organisation and cell adhesion, such as the
lectican family and phosphacan in the nervous system [7]. Although
pure HA is considered non-adhesive, it does contain some adhesion
sites which can be modified. For this reason, various modifications
are performed to create cell-adhesive regions within HA hydrogels,
and many materials may be incorporated into the HA, including
polylysine [20], RGD peptides [44, 45], laminin [21], gelatin [46],
dextran [47], and catechol [48]. With the strategies, Tian, Goubko
and their co-workers [20, 45] have confirmed that HA hydrogels
achieve good interactions with the cells, i.e., the improvement of cell
viability, and furthermore, regulation of cell growth, differentiation
and migration in the gel (
Figure 1.2
).
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