Biomedical Engineering Reference
In-Depth Information
targets for tissue engineering. In the last section, the prospects of
scaffolds forcardiovascular tissueengineering are also discussed.
26.2.2
Decellularized Tissue Scaffolds for
Tissue-Engineered Small-Caliber Vascular Grafts:
Methodology, Biocompatibility, and Mechanical
Properties
A decellularized technique has been developed to reduce immuno-
genicity and/or calcification of bioprostheses after implantation.
8
,
9
Advantages of using decellularized matrix for tissue engineering
have been reported by many researchers.
10
The most favorable
advantageofthedecellularizedscaffoldisthatitcanbeusedtogen-
erateacompletelyidenticalstructureofthetargetorgan/tissueeven
if the structure is extremely complicated.
Various cell extraction methods, including detergent treatments,
enzymatic digestion, and a combination of detergent and enzyme,
have been reported for decellularization. Triton X-100,
11
sodium
deoxycholate,
12
and sodium dodecyl sulfate (SDS)
13
are used as
detergents, and trypsin
14
is used as an enzyme to disassociate
the cells. As a unique method for decellularization, Fujisato
et
al
. reported the use of ultrahigh pressure.
15
Each method has
advantages and disadvantages, and optimization is necessary for
each organ/tissue. For example, we found that esophagus treated
with sodium deoxycholate showed superior mechanical proper-
ties, maintenance of extracellular matrix (ECM), and lower DNA
content than that treated with Triton X-100.
16
Conversely, the
degree of decellularization and maintenance of the matrix were
best in the Triton X-100-treated ureters, while Triton X-100-
treated and sodium deoxycholate-treated ureters had lower rem-
nant DNA content and immunogenicity than the other treatments
17
(Fig. 26.2).
In vitro
and
in vivo
biocompatibility of the decellularized scaf-
fold was satisfactory (Fig. 26.3). Endothelial cells were easy to seed,
and they adhered to the inner surface of the decellularized scaffold.
The seeded cells functioned
in vivo
because cell-seeded grafts were
foundtohaveanti-thrombogenicity.Biocompatibilityofthedecellu-
larized scaffolds depends on the native ECM, which may contribute
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