Tailor-Made and Biodegradable Vascular Scaffolds - Microsurgery: Advances, Simulations, and Applications - page 278

In previous studies, microscopic and macroscopic 3D porous
structures have been fabricated by various methods such as
particulate leaching [23, 24], electrospinning [25, 26], multilayer
lamination [27, 28], molding [29, 30], 3D printing [31, 32], and
phase separation [33]. Above all methods, particulate leaching has
the following absolute advantages compared with other techniques:
(i) The size of particulates can be controlled easily by using
sieves, thereby ensuring pores with controlled size.
(ii) Particulates can be packed in complex 3D structure, thereby
ensuring 3D porous scaffolds with arbitrary shape [34, 35].
(iii) Particulates such as salt or sugar do not solve in general
organic solvents and can be removed easily by water.
Two main techniques have been used to achieve well-connected
pores and high porosity inside the scaffolds by particulate leaching.
Murphy et al . proposed a way to improve pore connectivity by salt
fusion under moderate humidity and temperature [36]. On the other
hand, Wei et al . proposed another unique way to enhance the pore
connectivity by emulsiied sugar spheres [37]. Well-connected pores
with uniform diameter should be very useful for effective and fast
regeneration of tissue.
However, in addition to all of these previous efforts, self-
assembly of micro-scale particulates is also interesting and has
great potential to achieve high porosity and pore-connectivity in a
scaffold. While self-assembly of spherical particles is very attractive
to generate ordered array of pores inside a scaffold [38, 39],
magnetic self-assembly is very simple and eficient way to achieve
ordered 3D constructs [40, 41]. Here, we propose a way to develop
self-assembled templates for particulate leaching by encapsulating
ferrite microparticles inside sugar microspheres. The fabricated and
self-assembled magnetic sugar particles (MSPs) were utilized as a
template for magnetic sugar leaching (MSL). The developed scaffolds
after MSL had ordered, well-connected micropores. The mechanical
strength of a sheet-like scaffold was evaluated by tensile test and its
biocompatibility was conirmed by the viability of human umbilical
vein endothelial cells (HUVECs).

8.7.1 Preparation of Magnetic Sugar Particles

Poly(-lactide-co- ε -caprolactone, PLCL) (C LA : C CL = 52:48, Mw =
540,000) was purchased from BMG (Japan). -fructose (m.p. 102-