Biomedical Engineering Reference
In-Depth Information
13.1 Introduction
Electrospinning is the most elegant method for nanofiber pro-
duction, which was introduced in the early 1930s.
1
,
2
Recently,
much attention has been paid to the electrospinning process as a
unique technique, because it can produce polymer nanofibers hav-
ing a diameter in a range of several micrometers down to tens of
nanometers.
3
In addition, electrospun nanofibrous scaffolds pos-
sess an extremely high surface-to-volume ratio, tunable porosity, an
ability to conform over a wide variety of sizes and shapes, supe-
rior mechanical properties, and ease of controlling composition
to achieve desired properties and functionality.
4
All these advan-
tages of electrospun nanofibrous scaffolds have encouraged the
researchers more interested in the past several years to rigorously
investigatedifferentcompositematerialstofindtheirapplicationsin
variousfields,suchasfiltration,
5
opticalandchemicalsensors,
6
elec-
trode materials,
7
and biological/ biomedical scaffolds.
8
,
9
The elec-
trospinning method has been actively explored recently in regard
to biomedical fields. Natural polymers (i.e., collagen, gelatin, ker-
atin, silk, fibrinogen, elastin,
etc.
) and synthetic polymers—that is,
poly(lactic acid) (PLA), poly(glycolic acid) (PGA), poly(lactide-
co
-
glycolide)(PLGA),poly(
ε
-caprolactone)(PCL),PHBV,
etc.
—arebeing
co-electrospun to form nanocomposites in order to be used as
wound dressings,
10
drug delivery systems,
11
and vascular graft and
tissue engineeringapplications.
8
,
12
To use nanocomposites in biomedical fields, some properties
of composite materials, such as hydrophilicity, mechanical mod-
ulus and strength, biodegradability, biocompatibility, and specific
cell interactions, need to be considered.
4
By selecting a combina-
tion of appropriate components and by adjusting the component
ratio, properties of electrospun nanocomposites can be tailored to
have desired new functions. On the basis of polymer physics, poly-
mer blending, followed by electrospinning, constitutes one of two
effectivemeanstocombinedifferentpolymersinyieldingnewmate-
rials properties.
4
For example, mixtures of collagen with elastin
13
as well as mixtures of chitosan with poly(ethylene oxide) (PEO) or
poly(ethylene glycol) (PEG)
14
have been electrospun to fabricate
nanocompositesfor biomedicalapplications.
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