Biomedical Engineering Reference
In-Depth Information
Figure 36.2. Range of compressive moduli in selected papers for com-
mon matrices used for cartilage tissue engineering approaches (alginate, 14
agarose, 15 fibrin, 16 , 17 gelatin, 18 PEG, 19 *, 20 andExtracel 21 *),aswellasdepth-
dependent moduli in fetal 22 and adult 23 bovine articular cartilage. * indi-
cates an estimate based on three times the shear modulus.
synthetic. Each of these matrices exhibits certain features of the
articular cartilage matrix, which consists primarily of water (70%),
glycosaminoglycans(10%),andproteins(20%,mainlycollagentype
II). With this broad range of matrices, possibilities exist for provid-
ing specific environments to generate/maintain zonal differences
and to construct engineered tissues with zonal functions. In this
chapter, we will describe and discuss several popular hydrogel sys-
tems used in cartilage tissue engineering and techniques to utilize
these materials to generate advanced tissue-engineered cartilage
that more closely mimics the zonal structure and function of native
cartilage.
36.2 Carbohydrate-Based Matrices
Oneprominentfeatureofarticularcartilageistheabundanceof(sul-
fated) glycosaminoglycans in the extracellular matrix. These macro-
molecules, principally chondroitin-6-sulfate, but also chondroitin-
4-sulfate, keratan sulfate, dermatan sulfate, and others, provide a
fixed charge to the matrix and are responsible for the swelling and
compressive properties of the tissue. In cartilage, they are mainly
 
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