Biomedical Engineering Reference
In-Depth Information
β
of TGF-
3 into the scaffolds leads to roughly 130% more cells in the regenerated
cartilage than in the absence of TGF-
β
β
3-infused scaffolds
were fully covered with hyaline cartilage in the articular surface with similar me-
chanical properties as of the native cartilage, whereas TGF-
3. After 4months, TGF-
3-free scaffolds showed
inferior results such as only isolated cartilage formation with relatively lower den-
sity and thickness [
102
]. This approach may be useful for the cartilage part of an
OC regeneration strategy. In another study, Huang et al. [
103
] produced calcium
phosphate/poly(L-lactic acid) composite scaffolds that were incorporated with basic
fibroblast growth factor. The scaffolds were implanted into OC defects of rabbits
without in vitro cell seeding. It was reported that the defects were filled with regen-
erated tissue [
103
]. The surface was covered with a layer of cartilage tissue with a
good integration in the surrounding native tissue. In addition, high levels of collagen
type II and aggrecan were reported. With respect to SB regeneration, a continuous
layer of trabecular bone was formed below the cartilage [
103
].
As an alternative to the scaffolding materials used in the studies mentioned above,
decellularized tissues can also be used as scaffolds in tissue engineering applications.
Yang et al. [
104
] developed porous decellularized scaffolds from bovine articular
cartilage for cartilage regeneration. The scaffolds maintained the collagen and gly-
cosaminoglycan components of cartilage. Rabbit bone marrow MSCs were seeded
into the decellularized scaffolds. After implantation of constructs into the knee car-
tilage defects of rabbits, better histological scores were achieved as compared to
control groups. Small intestinal submucosa (SIS) has also been studied experimen-
tally for tissue engineering applications. To repair articular cartilage defects, Peel
et al. [
105
] seeded chondrocytes onto porcine SIS to generate cartilaginous tissue.
Full-thickness articular cartilage defects were treated with these constructs. Based
on that work, it was suggested that the SIS-cartilaginous tissue constructs might be
useful for joint resurfacing. The results of a study with SIS performed by Suckow
et al. [
106
] also suggested that SIS may be a promising biomaterial for bone repair.
β
2.5 Multiscale Tissue Engineering and Regenerative Medicine
Strategies
The current trend in TERM is towards multiscale strategies in which different fields
of expertise such as tissue engineering, information technology, and medical imaging
collaborate. This part briefly overviews these multiscale approaches. The Laboratory
for Multiscale Regenerative Technologies (
http://lmrt.mit.edu/
)
directed by Sangeeta
Bhatia, is researching micro- and nanotechnology applications for tissue repair and
regeneration. They study how micro-environmental signals influence fate and func-
tion of liver cells and use this knowledge to develop robust models of animal and
human liver for in vitro [
107
] and in vivo studies. They use microelectronic circuits
[
108
] to study the role of cell-cell interactions in liver constructs, and to use novel
extracellular matrix microarrays [
109
] to study the role of matrix combinations in
liver functions. Moreover, their studies include hydrogels, stem cells, and bioreactors
