Biomedical Engineering Reference
In-Depth Information
synthetic polymers serve as mechanical skeletons to provide
hybrid scaffolds with high mechanical strength to retain their
designed shapes and sizes, while the naturally derived polymers
contribute to good cell interaction and hydrophilicity to facilitate
cell seeding and cell attachment. Hybrid porous scaffolds have
been used for tissue engineering of a number of types of tissues.
Recent developments of hybrid scaffolds and their application to
tissue engineering are summarized.
22.1 Introduction
Tissue engineering and regenerative medicine have been widely
usedtotreatdefectiveandmalfunctioningtissuesandorgans.
1
Some
tissue-engineered products have been used for clinical applications,
and some have been commercialized. A few methods have been
developed in the approach for tissue engineering and regenerative
medicine.Theyincludecelltherapy,scaffold-free,andscaffold-aided
methods.
2
-
4
Celltherapybydirectlyinjectingorapplyingsomaticor
stem cells to cleaned foci can be performed in low-invasive meth-
ods; however, the diffusion of cells from the foci has been a chal-
lenging issue. Reconstruction of tissues and organs by scaffold-free
methods such as pellet culture and cell sheet engineering can avoid
anyundesirableeffectsfrommaterials.Regenerationoflargetissues
and organs with complicated shapes by the scaffold-free method
remains a challenge. The scaffold-aided method provides a scaffold
to accommodate the seeded cells, to support cell adhesion and pro-
liferation, and to guide the formation of tissue in the scaffold. The
cells can be held together by the scaffold in large tissues and organs
with complicated structures of specific shapes. Bioactive molecules
can also be incorporated in the scaffold and their release controlled
temporally and spatially to trigger a cascade of signaling events
to direct cell functions. Scaffolds can also be designed to mimic
the structures of extracellular matrices to provide cells with bio-
mimetic
in vivo
microenvironments.However,thebiomaterialsused
for scaffolds must be biocompatible and biodegradable to decrease
or remove any side effects from the scaffold materials. The scaffold-
aided method has been used for the tissue engineering of many
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