Biomedical Engineering Reference
In-Depth Information
Even though cells in combination with HA scaffolds show great
potential for cartilage repair, additional components could be
combined with the constructs to improve chondrogenesis. For
example, growth factors from the transforming growth factor
beta (TGF-β) superfamily have been shown to lead to robust
chondrogenesis and reduced hypertrophy [69].
In vitro
and
in vivo
,
MSC encapsulated together with TGF-β3 in HA scaffolds displayed
enhanced chondrogenic potential compared to PEG scaffolds with
TGF-β3 or HA scaffolds without TGF-β3 [70, 71].
2.6 Combined Scaffolds for Cartilage Regeneration
As described above, scaffolds made of HA alone demonstrate
potential for use in cartilage regeneration. However, HA has also
been combined with synthetic polymers, which provide the ability to
fine tune the properties of the scaffold, as well as with other natural
materials. This section provides several examples of these hybrid
materials systems.
2.6.1 Delivery of Chondrocytes
Rabbit chondrocytes seeded on chitosan:HA hybrid scaffolds
synthesised significantly more aggrecan than chondrocytes on pure
chitosan scaffolds
in vitro
[55]. The chondrocytes further maintained
their circular morphology and produced a collagen II rich ECM [55].
In vivo
, this combination of chitosan and HA with chondrocytes
led to better integration of the scaffold with the surrounding tissue
and maintenance of cell morphology [56]. In another example, the
incorporation of a small amount of HA (2% w/w) in a 3D collagen
sponge enhanced
in vitro
matrix accumulation and chondrogenic
gene expression of bovine articular chondrocytes when compared
to pure collagen sponges, but a higher concentration of HA (10%
w/w) hindered the process [52].
Another study combining PEG with
collagen, HA, and CS showed that specific formulations led to a
differential response of encapsulated bovine chondrocytes from
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