Hyaluronic Acid Hydrogel: A Favourable Niche for Neural Stem Cells - Hyaluronic Acid for Biomedical and Pharmaceutical Applications - page 7

NgR antibody can be used for experimental therapy of a rat model
with a hemisection in the spinal cord. The gels significantly promoted
the axon extension and myelinisation 8 weeks after implantation.
The gels were particularly shown to have remarkable advantages
in supporting angiogenesis, and simultaneously inhibiting glial scar
formation.
1.3.3 Other Modifications
The HA hydrogel can be chemically modified in many different ways
in order to achieve a better ECM-like component and architecture,
to promote its interaction with cells. PLL is usually used as a coating
substrate on the surface for cell adhesion when being cultured
in vitro . It can be taken into the gel for the modulation of neuronal
cell adhesion and neural network formation. The report by Tian and
co-workers [20] has shown that this modified hydrogel has good
compatibility with the cells and surrounding tissue in the brain.
An ECM protein, laminin, which participates in neuronal development
and survival, can be immobilised on the backbone of the HA hydrogel,
and this has been proven by Hou and co-workers [21]. In this case, the
gel still possesses the mechanical properties and rheological behaviour
similar to brain tissue. After being implanted into a cortical lesion it
promotes neurite extension and angiogenesis into the porous scaffold,
and simultaneously inhibits glial scar formation.
Additionally, the tripeptide of arginine, glycine and aspartic acid
(RGD), is the cell attachment site of ECM. For this reason, it is
widely used in tissue engineering materials. Cui and co-workers
[42] have reported that the HA hydrogels modified with RGD can
be implanted into the cortical lesion in rats. It provides a continuous
structure across the defect and reorganises the local cells, axons and
blood vessels growing into the gel scaffold. Meanwhile, the injectable
HA hydrogel reported by Shu and co-workers [43], modified with
RGD peptides, was shown to significantly enhance the proliferation
of fibroblasts on the gel surface.