EN
Bone is a composite tissue composed of an
organic matrix, inorganic mineral matrix and water.
Structurally, bone is organized into two distinct types:
trabecular (or cancellous) and cortical (or compact) bone.
Cortical bone is highly organized, dense and composed of
tightly packed units or osteons whereas trabecular bone
is highly porous and usually found within the confines
of cortical bone. Osteons, the subunits of cortical bone,
consist of concentric layers of mineralized collagen
fibers. While many scaffold fabrication techniques have
sought to replicate the structure and organization of
trabecular bone, very little research focuses on mimicking
the organization of native cortical bone. In this study
we fabricated three-dimensional electrospun cortical
scaffolds by heat sintering individual osteon-like scaffolds.
The scaffolds contained a system of channels running
parallel to the length of the scaffolds, as found naturally
in the haversian systems of bone tissue. The purpose
of the studies discussed in this paper was to develop a
mechanically enhanced biomimetic electrospun cortical
scaffold. To that end we investigated the appropriate
mineralization and cross-linking methods for these
structures and to evaluate the mechanical properties
of scaffolds with varying fiber angles. Cross-linking the
gelatin in the scaffolds prior to the mineralization of the scaffolds proved to help prevent channels of the osteons
from collapsing during fabrication. Premineralization,
before larger scaffold formation and mineralization,
increased mineral deposition between the electrospun
layers of the scaffolds. A combination of cross-linking and
premineralization significantly increased the compressive
moduli of the individual scaffolds. Furthermore, scaffolds
with fibers orientation ranging between 15° and 45° yielded
the highest compressive moduli and yield strength.