Biomedical Engineering Reference
In-Depth Information
polyglycolic acid (PGA) scaffold falls into the category of synthetic
polymers and was the first scaffold used for pioneering research
of tissue engineering.
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Different from natural scaffolds, synthetic
polymers can be designed and manufactured for their exact degrad-
ability and degradation time, as well as their pore size and poros-
ity and other physical and chemical properties. Thus the quality of
synthetic scaffolds can be better controlled compared with natural
scaffolds. This allows for reproduction in large quantities with simi-
larcharacteristics.Additionally,duetothenatureofartificiallymade
substances, they can avoid the risk of transferring pathogens to the
host, which possibly reside in human and animal tissues, such as
prionandviruses.Amongdifferentsyntheticpolymers,PGAbelongs
to the group of poly (
α
-hydroxy acids).
The poly (
α
-hydroxy acids) are hydrolyzed by cleavage of their
ester bonds in a water-containing environment, which results in a
reduction of molecular weight, but not the total mass, of the scaf-
fold. The degradation via hydrolysis usually reduces the molecu-
lar weight to around 5,000. Afterward, cellular degradation takes
over the degradation process to further degrade the polymer into
monomers, and they are finally metabolized into water and CO
2
.
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Due to this nature, poly (
α
-hydroxy acids) are considered one of the
optimal synthetic scaffoldsfor tissue engineering.
OneofthecommonphysicalformsforaPGAscaffoldistheunwo-
ven PGA fibers, which were originally reported as being a scaffold
by Langer's group and Vacanti's group.
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According to literature,
unwoven PGA fibers have been widely applied to the engineering of
varioustypesofsofttissue,includingskin,tendon,cartilage,corneal
stroma, blood vessels, etc.
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,
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This chapter will provide a review of
their application in soft-tissue engineering.
34.2 PGA Fibers for Tendon Engineering
Tendonsaretheconnectivetissuethatlinksmusclestobonessothat
the tensile force created by muscles can be transmitted to bones for
bodymovement.Themaintendonextracellularmatrix(ECM)istype
I collagen, which is highly organized in a hierarchy of bundles that
are aligned in a parallel fashion. This unique structure provides the
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