Biomedical Engineering Reference
In-Depth Information
subsequently freeze-dried and covalently cross-linked to
yield biomaterials that have been shown capable of in-
ducing regeneration of skin (dermis), peripheral nerves,
and the conjunctiva (
Table 3.2.8-2
).
and degrading all adjacent substances. It appears to be
highly amorphous and thus has eluded elucidation of its
structure by crystallographic methods. Fortunately, it
exhibits ideal rubber elasticity and it thus becomes pos-
sible to study certain features of the macromolecular
network. For example, mechanical measurements have
shown that the average number of amino acid units be-
tween cross-links is 71-84. Insoluble elastin preparations
can be degraded by the enzyme elastase. The soluble
preparations prepared thereby have not yet been applied
extensively as biomaterials.
Elastin
Elastin is one of the least soluble protein in the body,
consisting as it does of a three-dimensional cross-linked
network. It can be extracted from tissues by dissolving
Hyaluronic acid
Dermatan sulfate
COOH
CH
2
OH
CH
2
OH
HO
3
SO
O
O
O
O
COOH
O
O
O
O
OH
O
O
OH
HO
HNCOCH
3
OH
OH
HNCOCH
3
n
n
β
1,3 Linkage
Chondroitin 6-sulfate
Keratan sulfate
CH
2
OSO
3
H
CH
2
OSO
3
HCH
2
OSO
3
H
COOH
HO
HO
O
O
O
O
O
O
O
O
OH
O
OH
O
HNCOCH
3
OH
HNCOCH
3
OH
n
β
1,4 Linkage
n
Heparan sulfate
CH
2
OH
CH
2
OH
COOH
O
O
O
O
COOH
O
O
OH
OH
OH
OH
O
O
O
HNSO
3
H
OSO
3
H
HNCCH
3
OH
n
O
Heparin
H
2
COSO
3
H
H
2
COSO
3
H
COOH
O
O
O
O
COOH
O
OH
O
OH
OH
OH
O
O
O
HNSO
3
H
OSO
3
H
OH
HNSO
3
H
n
Fig. 3.2.8-4 Repeat units of GAGs. (Reprinted from J. Uitto and A. J. Perejda, editors (1987). Connective Tissue
Disease, Molecular Pathology of the Extracellular Matrix, Vol. 12 in the series The Biochemistry of Disease. Marcel Dekker, New York,
Chap. 4,
Figs. 3.2.1
and
3.2.2
, p. 85, with permission.)
