Biomedical Engineering Reference
In-Depth Information
aligned nanofibers were explored to fabricate tubular scaffolds that
could be used for engineering blood vessels. Their results demon-
strated that nano-sized fibers mimic the dimensions of the nat-
ural ECM, provide mechanical properties comparable to the human
coronary artery, and form a well-defined architecture for smooth
muscle cell (SMC) adhesion and proliferation.
20
Aligned fibers not
only give structural integrity but also maintain vasoactivity as
they provide the necessary mechanical strength needed to sustain
high pressure of the human circulatory system.
21
Scientists stud-
ied the response of endothelial cells along with SMCs on the aligned
nanofibersofPLLA-CL,andtheirresultsdemonstratedthatboththe
cell types showed enhanced adhesion and proliferation rates on the
nanofibrous scaffold.
21
In addition, it was observed that the SMCs'
cytoskeletonorganizationwasalongthedirectionofthenanofibers.
These results suggested that aligned nanofibers may provide for a
goodscaffolding system for vascular tissueengineering.
PLA
/
PCL bilayered tubular scaffolds with a PCL inner layer of
randomly oriented microfibers (1.5-6
μ
m) and a PLA outer layer
composed of oriented fibers with diameters from 800 nm to 3
μ
m have been fabricated. The outside is composed of concentric
layers of circumferentially oriented PLA fibers analogous to the
tunica media layer of blood vessels. The concentric inner layers
of randomly oriented PCL fibers represent the elastic lamina and
tunica intima layers of a blood vessel. The bilayered PLA
/
PCL
scaffolds have a maximum stress of 4.3 MPa and an elastic defor-
mation up to 10% strain, which is strong enough and may pro-
vide the compliance necessary for substitute blood vessels. Cellular
attachment, spreading, and proliferation are proven on these bilay-
ered scaffolds using mouse fibroblasts and human venous myofi-
broblasts.Thefibroblastsadheredandproliferatedalongthealigned
fibrous network, revealing high cellular densities on the outer layer
comparedwiththeinnerlayerover30daysofstaticculture.Itisnow
established that there is a significant effect of nano-scale-textured
surface roughness on cell response in terms of cell adhesion and
proliferation. It is also known that cells attach and organize very
well around fibers with diameters smaller than them.
21
Their study
demonstrated enhanced spreading and proliferation of endothe-
lial cells on modified polyethylene terephthalate (PET) nanofiber
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