Biomimetic Polysaccharides and Derivatives for Cartilage Tissue Regeneration - Biomimetics: Advancing Nanobiomaterials and Tissue Engineering - page 5

for use in tissue, engineered for effective cartilage repair. Such a physi-
cal form of scaffold mainly depends on the method of fabrication pro-
cess, and chemical and physical properties of scaffold materials. For tissue
regeneration the method of cell seeding and distribution within the scaf-
fold play an important role and can dictate cell infi ltration into the scaf-
fold. The method of cell seeding selection, either static or dynamic, can
also depend on the physical form of the scaffolds. The later cell seeding
method (dynamic) can improve cellular distribution in the case of sponge
and mesh types of scaffold [11], whereas hydrogel-based scaffolds typi-
cally support uniform cell distribution if cells are adequately suspended
during gelation [12].
To date, a wide range of synthetic and natural polymers have been
investigated to synthesize scaffold for cartilage regeneration. However,
synthetic polymers do not have direct cell-scaffold interactions, and the
degradation by-products may be toxic or elicit an infl ammatory response.
The natural polymers which have been investigated as possible bioac-
tive scaffolding materials for cartilage engineering include: chitin and
chitosan, hyaluronic acid (HA), alginate, starch, cellulose, agarose, fi brin,
collagen, gelatin, and chondroitin sulphate (Table 1.1) [5-33]. These poly-
mers can often interact with cells via cell surface receptors, and regulate or

Table 1.1 Types of natural polymers used as scaffolding materials for
cartilage tissue engineering.

Natural
Polymers

Advantages Disadvantages References

Agarose Injectible and

cells can be
uniformly
distributed
within implant.

Foreign body giant
cell reaction.
Low resorbtion.
Biochemical
properties sig-
nifi cantly infe-
rior to native
tissue.

[2, 7, 8]

Alginate Easy to cross-

linked to form
gel under very
mild condi-
tions. Gel can be
injected to avoid
an open surgical
procedure.

Lack of mechani-
cal strength
and handling
properties, dif-
fi cult to steril-
ize. Impurities
affecting mate-
rial properties.

[2, 7]

( Continued )