Biomedical Engineering Reference
In-Depth Information
Figure 31.10. (a) The fiber deposition device and (b) the 3D deposition
process where 250 μ m PEGT/PBT fibers are successively laid down in a
computer-controlledpattern(0 -90 orientationshown).Scaffoldsaresub-
sequently cored from the deposited bulk material.
evidenced by extensive cell adhesion and proliferation. Further,
they are suitable for in vitro osteochondral constructs in tissue
engineering.
Woodfield et al . developed and characterized a fiber depo-
sition technique for producing 3D PEG-terephthalate (PEGT)-
poly(butylene terephthalate) (PBT) block copolymer scaffolds with
a 100% interconnecting pore network for the engineering of artic-
ular cartilage (Fig. 31.10). 32 By varying the PEGT/PBT composition,
porosity, and pore geometry, 3D-deposited scaffolds were produced
with an equilibrium modulus and a dynamic stiffness ranging from
0.05to2.5MPaand0.16to4.33MPa,respectively.The3D-deposited
scaffolds supported the rapid attachment of bovine chondrocytes
and tissue formation following dynamic culture in vitro and subcu-
taneous implantation in nude mice, as demonstrated by the pres-
ence of articular cartilage extracellular matrix (ECM) constituents,
glycosaminoglycan(GAG),andtypeIIcollagenthroughouttheinter-
connected interior pore volume. Similar results were achieved with
respect to the attachment of expanded human articular chondro-
cytes,resultinginahomogenousdistributionofviablecellsafterfive
days ofdynamic seeding.
Wang et al . developed the precision extruding deposition (PED)
system. 33 In contrast to the conventional FDM process, which
requires the use of precursor filaments, the PED process directly
extrudes scaffolding materials in a granulated or pellet form
withoutfilamentpreparationandfreeformdepositsaccordingtothe
 
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