Biomedical Engineering Reference
In-Depth Information
off-the-shelf availability may make such scaffolds especially ben-
eficial for clinical use. The effect of growth factors bound to the
scaffolds will be illustrated in a rat subcutaneous model.
20.1 Introduction
Cells signal to the ECM as much as the ECM signals to cells. All
cells are surrounded by ECM molecules, which provide specific cues
to the cells with regard to cellular processes, like proliferation,
differentiation, migration, and cell-matrix interactions.
1
Since cells
behave in a different way on various surfaces, one can use the sur-
rounding matrix to guide cells in a certain direction.
Our aim is to engineer molecularly defined “smart” scaffolds
which signal to the surrounding cells which tissue/organ to form.
If one wants to study the effect of single ECM components on cell
behavior and tissue remodeling, it is important to use highly puri-
fied components. Therefore, we have put considerable efforts into
the purification of insoluble (fibrillar) type I collagen, insoluble
elastin fibers and solubilized elastin.
2
-
4
From these basic compo-
nents, tailor-made biomaterialscan beproduced.
5
Nexttothemolecularmakeupofscaffolds,thethree-dimensional
architecture is of major importance.
6
Cells in a porous bioscaffold
typicallysynthesizetheirnewECMmoleculesaligningthepresented
scaffold,
7
,
8
and this offers the opportunity to direct the orientation
of newly formed ECM. In such a way, the basket-weave collagen
meshwork of normal skin may be mimicked in case of skin trauma,
thuspreventingtheformationofdenselyalignedbundlespresentin
scars,
9
thereby reducing scarring.
In this chapter, we will show the fabrication of collagen-/elastin-
based scaffolds with a defined structure (dense flat films, porous
scaffolds with various pore/lamellae structures, and tubular scaf-
folds), as well as scaffolds with a defined molecular composition,
especially related to the incorporation of glycosaminoglycans and
growth factors. An
in vivo
study using such acellular scaffolds
will be presented, viz., the application of scaffolds with heparin
and growth factors to boost angiogenesis in a rat subcutaneous
model.
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