Biomedical Engineering Reference
In-Depth Information
surface micro- and nano-porosity, and orientation of the spun fiber
canbecontrolledbytypesofpolymers,solvents,devisesettings,etc.
Nano-electrospinning of PGA, PLA, PLGA, caprolactone copolymers,
collagen, elastin, etc., has been extensively developed, as depicted
in section 1.4.
5
,
38
For example, electrostatic processing can consis-
tentlyproducePGAfiberdiametersatorbelow1
m.Bycontrolling
thepickupofthesefibers,theorientationandmechanicalproperties
can be tailored to a specific need of the injured site. Also, collagen
electrospinning was performed utilizing type I collagen dissolved in
1,1,1,3,3,3-hexafluoro-2-propanol with 0.083 g/mL concentration.
TheoptimallyelectrospuntypeIcollagennonwovenfabricappeared
withanaveragediameterof100
±
40nm,resultinginbiomimicking
fibrous scaffolds.
Bioactive molecules-loaded electrospinning nanofibers could be
also fabricated by the controlling of the manufacturing factor; thus
the application of this ECM-mimicking scaffolds has been expanded
as multifunctionalregenerative medicineand tissue engineering.
μ
1.3.1.2 PGA nonwoven sheet
The most common and commercialized one is the PGA nonwoven
sheet with porosity around 97% and 1
∼
5 mm thickness, which is
tested almost of tissue-engineered organs. The fiber diameter is
13
∼
14
μ
m, and it will be swelling to 20
μ
m after the immersion
in a cell culture medium. The monofilament of PGA for the suture
was fabricated into a nonwoven sheet by needle punch. In order to
stabilize dimensionally and provide mechanical integrity, the fiber-
bonding technology by heat and by PLGA or PLA solution spray-
coating methods were developed.
39
Figure 1.4 shows the shape of
nose and ear tissue-engineered products as hybrid reticular carti-
lage from rabbit chondrocytes and PGA nonwoven fibers. Recently,
fibrous woven andknitted 3D scaffoldshave been suggested.
1.3.1.3 Porogen-leaching methods
Porogen-leaching methods are combined with polymerization, sol-
vent casting, gas foaming, or compression molding of natural and
synthetic scaffolds biomaterials with leaching of pore-generating
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