Biomedical Engineering Reference
In-Depth Information
5.
Titanium Fiber Mesh: A Nondegradable
Scaffold Material
Juliette van den Dolder and John A. Jansen
5.1 Introduction
and cell-based approaches. In the growth-
factor-based approach, the scaffold material
is loaded with specifi c bone-inductive growth
factors prior to implantation. These exogenous
growth factors are then released at the implant
site, where they can act upon locally resident
cells as well as recruiting other, more distant
cells to form new bone tissue. A signifi cant
number of growth factors are commercially
available for this purpose. In the second
approach, the scaffold material is preseeded
with osteogenic cells to promote bone forma-
tion. When these cell/scaffold constructs are
cultured in vitro for an extended period of
time, the seeded cells secrete matrix as well as
other growth factors into the scaffold. At the
implant site, these cell/scaffold constructs con-
tribute to bone formation. In the cell-based
approach, bone marrow cells often are used for
creating a cell/scaffold construct.
The objective of this chapter is to summarize
the results achieved with the nondegrad-
able scaffold, titanium fi ber mesh, for use as
a bone-engineered construct. This material
has been used in both strategies, the so-called
cell-based
The grafting of bone in skeletal reconstruction
has become a common task of the orthopedic
surgeon. The need for reconstruction or
replacement is often the result of trauma, con-
genital malformations, or cancer. Reconstruc-
tive surgery is based upon the principle of
replacing defective tissue with viable, function-
ing alternatives. Various materials have been
used to treat the defects, including autogenous
bone and alloplastic materials. Grafting mate-
rials are necessary to bridge defects or to
increase the bone volume. At present, autolo-
gous bone is the gold standard, but it has
important disadvantages, including donor-site
morbidity, limited availability, and unpredict-
able resorption characteristics. These factors
have stimulated the search for other materials
that can replace autogenous bone. Allografts
and xenografts, although suitable in texture
and content, have limitations that include the
capacity of transmitting disease and gener-
ating an immunogenic response. A recently
developed approach to the reconstruction or
regeneration of lost or damaged body tissues is
tissue engineering, which involves the fabrica-
tion of a so-called three-dimensional autolo-
gous tissue construct.
Although tissue engineering can be applied
in many clinical situations, much attention
is paid to the engineering of bone tissue. Two
different strategies can be followed to achieve
this goal, including both growth-factor-based
and
the
growth-factor-based
approaches.
5.2 Scaffolds
In the fi eld of bone tissue engineering, various
combinations of naturally derived and syn-
thetic polymers, composites, ceramics, and
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