Tailor-Made and Biodegradable Vascular Scaffolds - Microsurgery: Advances, Simulations, and Applications - page 276

Results indicate that patient-speciic biodegradable scaffolds
could be successfully fabricated by the proposed method. Inside the
PLCL scaffolds, pores of less than 100 μ m in diameter were created
as shown in Figs. 8.3(c-d), indicating that NaCl microparticles were
successfully leached out.
As shown in Fig. 8.5, the thickness of the PLCL membrane
was mainly affected by the concentration of PLCL in chloroform.
Because polymer solutions with higher PLCL concentrations have
higher viscosity, they are less affected by gravity during pull-up. The
thickness of a human artery is on the order of hundreds of microns.
Figure 8.5 shows that the thickness of PLCL could be controlled from
tens of micron to a millimeter.
Young's modulus for human blood vessel is between 1 and 3 MPa.
As shown in Fig. 8.6, the results of tensile tests indicated that Young's
modulus for these PLCL scaffolds covers this range. For the fabrication
of artiicial carotid arteries, a composition of 5 w% PLCL and 3.3 w%
NaCl in chloroform (PLCL : NaCl = 60 : 40 w%, Young's modulus =
1.8 MPa) was selected. This Young's modulus is close to that of the
human artery. In addition, the trend for a higher Young's modulus at
lower porosity and higher PLCL concentration is reasonable. When
implanting artiicial blood vessels, it is desirable that the artiicial
blood vessel matches that of the internal blood vessel. Young's
modulus of blood vessel walls varies among individuals due to age
or artery disease. Thus, the ability to control the coniguration and
Young's modulus of scaffolds is extremely useful for patient-speciic
surgery.
The size limitation of this method is the minimum reproduction
of 1 mm of inner diameter. However, this coverage is adequate for
vascular treatment because most vascular regions treated during
surgery have diameters greater than 1 mm. The laminating pitch of
rapid prototyping [18] results in rough resolution relative to soft-
lithography [19]. However, in scaffold fabrication, a laminating pitch
of 13 μ m is small enough compared to the diameter of the NaCl
microparticles (100

μ

m). Therefore, rapid prototyping is appropriate
for the development of porous scaffolds.
Here, we presented a novel method for scaffold fabrication using
rapid prototyping, lost wax, dip coating, selective dissolution, and
salt leaching processes. This allowed the successful development
of a patient-speciic biodegradable scaffold based on CAD data of
a carotid artery obtained from CT images. Young's modulus of the