Biomedical Engineering Reference
In-Depth Information
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caprolactone) (PCL) nanofi bers as scaffolds for cartilage tissue engineering. Fetal
bovine chondrocytes (FBCs) cultured on these scaffolds displayed a rounded or
spindle shaped morphology that is typical of chondrocytes in contrast to the fl at-
tened and spread fi broblast like morphology that was observed on the tissue
culture polystyrene (TCPS) surface. Moreover, a 21-fold increase in cell growth
and upregulation in gene expression of collagen type II confi rmed the potential
of PCL nanofi bers in cartilage tissue engineering. In another study, Li et al. [255]
studied the infl uence of electrospun PCL scaffolds on the behavior of MSCs.
Their results demonstrated that the MSCs preserved their phenotype on PCL
nanofi bers and in presence of transforming growth factor ß1 (TGF ß1), MSCs
seeded on PCL nanofi bers differentiated into a chondrocytic phenotype.
Electrospun nanofi brous scaffolds mimic the dimensions of collagen fi brils
present in the native ECM. These nanofi bers maintain the phenotype of chondro-
cytes seeded on their surface. Studies have demonstrated that chondrocytes
exhibit different proliferation rates on fi ber having different diameters. Li et al.
demonstrated a signifi cant increase in production of cartilage specifi c markers
such as collagen type II and type IX, aggrecan and COMP on the electrospun
fi bers having diameter in the nanometer scale (500-900 nm) as compared to the
fi bers having diameters in the micrometer range (15-20
Li et al. [254] described the potential application of electrospun poly(
ε
m) [251] . Thus, the
results indicated that electrospun nanofi brous scaffolds provide a more condu-
cive environment to chondrocytes as compared to microfi brous scaffolds.
The aforementioned studies demonstrated that electrospun nanofi bers show
potential for use as scaffolds in cartilage tissue engineering.
μ
13.5.2.3 Skeletal Muscle.
Skeletal muscle is a type of striated muscle that
comprises the single largest organ of the human body, forming 48% of the human
body by mass. It is not only highly organized at the microscopic level (a require-
ment to perform function), but is also compartmentalized when observed macro-
scopically. Skeletal muscles are composed of bundles of well organized, dense
myotubes that are packed in a parallel arrangement to form a muscle fi ber. Each
fi bril in turn is a multi-nucleated cell derived from myoblasts. The extracellular
matrix in skeletal muscle tissue comprises of glycoproteins, collagen (mainly type
I and III) and proteoglycans. These extracellular components govern the response
to tensile stress. In particular, collagen crosslinking and fi bril organization largely
determine muscle elasticity [256].
Defects in skeletal muscle make it incapable of responding to nervous control
and can lead to various genetic disorders such as muscular dystrophy and spinal
muscle atrophy [256]. Muscle structural anomalies can also result from trauma,
from tumor ablation, and even from continuous denervation.
The functional restoration of lost skeletal muscle through free tissue transfer
from near or distant sites, although common, has been the only alternative [257].
This method has received very limited success primarily due to donor site mor-
bidity and functional loss. Hence, muscle tissue engineering has been explored as
an exciting alternative.
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