MECHANO-ACTIVE SCAFFOLDS - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 542

independently by adjusting the fractions and sizes of particles used
(Fig.27.2e,f).WehaveusedtubularPLCLscaffoldsfabricatedbythe
extrusion-particulate leaching technique as mechano-active scaf-
folds for the application of cultured, small-diameter blood vessels.
However, these extruded PLCL scaffolds are limited in mechanical
strength, and vessel tensile properties are fundamental factors with
which to evaluate scaffolds for vascular tissue engineering applica-
tions. In particular, the tensile strength of scaffolds is an important
element for a successful vascular graft because vascular grafts must
have adequate strength to resist rupture or excessive dilation when
subjected to pulsatile pressures during implantation.
Therefore, a seamless tubular fibrous scaffold was fabricated
from PLCL (50:50, molar ratio) to overcome the limited mechan-
ical strength of extruded PLCL scaffolds by a custom-made gel-
spinning molding device 21 (Fig. 27.4A). The gel-spinning molding
device includes three separate drivers that make a cylindrical shaft
turn on its axis and orbit and concurrently move up and down.
A viscous PLCL solution in CHCl 3 was injected through a nozzle
into a methanol bath, as shown in Fig. 27.4B. The injection of the
PLCL solution into the methanol resulted in the solidification of
PLCL as a fiber form, due to exchange of methanol in CHCl 3 and
methanol in PLCL. The PLCL fibers were subsequently processed
to produce a seamless tubular scaffold on the rotating cylindrical
shaft, which was connected with the gel-spinning molding device,
in the methanol bath. The distinctive moving of the cylindrical shaft
in the methanol bath allowed the fibers to be spun and fabricated
without excessive aggregation. The fibrous, tubular PLCL scaffolds
showed good mechanical strength and cell adhesion and prolifera-
tione cienciescomparedwithPLCLtubularscaffoldsfabricatedby
the extrusion/particulate-leaching method.
27.2.3 Seamless Double-Layered Scaffold
In a different strategy, we used a gel-spinning molding tech-
nique to fabricate a double-layered tubular scaffold with high
mechanical strength and elasticity. Our aim was to develop a
seamless tubular PLCL scaffold that would resist rupture or leak-
age under high pressure to be applied for the implantation of