Biomedical Engineering Reference
In-Depth Information
graduallyevaporates,leavingacontinuousfiberthataccumulateson
the collector target.
Orientationcanbecontrolledthroughrotationandtranslationof
the collector drum while collecting the fibers. This process results
in the production of a nonwoven fibrous matrix. These matrices can
have a fiber diameter in the order of nanometers to microns. The
structure, produced by the electrospinning process, is a nonwoven,
3D, porous, and nano-scalefiber-basedmatrix.
Another actively investigated area of the application of poly-
meric nanofibers is the biomedical field.
11
Both nondegradable
and degradable polymers have been investigated for various
applications. As early as 1977, it was proposed that nondegradable
polymeric nanofibers can be used for developing prosthetic med-
ical devices such as blood vessels and vascular grafts.
12
Recently it
has been shown that electrospinning can be used to create porous,
thin films with structural gradients and controlled morphology on
prostheticdevicesinordertofacilitatetheintegrationofthedevices
with the body and thereby enhance their biocompatibility. One of
themajordriversofthisprogressisthepotentialuseofnanofibrous
structures as scaffolds for engineering tissues in regenerative medi-
cine. Electrospun fibers are capable of emulating the nanofibrous
architecture of the native extracellular matrix (ECM).
3
They can
potentially provide
in vivo-
like nanomechanical and physicochem-
ical signaling cues to the cells to establish apposite cell-scaffold
interactions and promote functional changes between and within
cells toward the synthesis of a genuine ECM over time. They are
of particular interest in regenerative medicine and tissue engineer-
ing because they can be potentially tailored to mimic the natural
ECM in terms of structure, chemical composition, and mechanical
properties.
3
,
5
Inthiscontext,theyserveasscaffoldstodirectcellular
behavior and function until host cells can repopulate and resynthe-
sizeanewnaturalmatrix.TheECMmolecularnetworksurrounding
the cells provides mechanical support and regulates cellular activi-
ties.ThenaturalECMinhumantissueismainlycomposedofproteo-
glycans (glycosaminoglycan [GAG]) and fibrous proteins, both with
nano-scale structural dimensions. Studies have shown that scaf-
folds with nano-scale structures support cell adhesion and prolifer-
ation and function better than their microscale counterparts. In this
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