Biomedical Engineering Reference
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Fig. 5 Vertical distribution of the fibrillar fibronectin network (stained with fluorochrome
conjugated antibodies) around endothelial cells (stained with CellTrackerGreen (Invit-
rogen)) after 5 days of cell culture on two polymer substrates with different anchorage
strength [ left —poly(octadecene- alt -maleic anhydride), right —poly(ethylene- alt -maleic
anhydride)]. The insets show the lateral network pattern ( scale bar : 100 µ m). Visualiza-
tion and analysis was performed on a confocal laser scanning microscope (TCS SP1,
From the reported findings one can conclude that gradated physicochemi-
cal characteristics of polymer substrates can be used to control the anchorage
strength of extracellular matrix proteins. By the force sensitive cell surface
receptors and the intracellular signalling mechanism the modified matrix
characteristics subsequently affects not only cell adhesion and matrix reorga-
nization, but furthermore cellular development in terms of differentiation. In
a more general sense these findings can nicely be discussed in the concept of
the “tensegrity” model [104], which combines extracellular signals like me-
chanical and structural features with intracellular processes like proliferation
and differentiation.
Collagen Fibrils and Collagen-Glycosaminoglycan Cofibrils
on Planar Surfaces and in 3D Carrier Materials
to Imitate the Hematopoietic Niche
Various processing techniques have accompanied the reconstitution of colla-
gen I-based cell scaffolds. In particular, chemical crosslinking or irradiation
were widely applied not only to enhance the mechanical properties of the
resulting materials but also to alter the degradation characteristics towards
slower changes [105, 106]. As collagen type I specifically interacts with nearly
50 ligands, among them other extracellular matrix components, and growth
and differentiation factors [107] another option consists of the in vitro deco-
ration of collagen type I fibrils with different biopolymers such as fibronectin,
vitronectin, or glycosaminoglycans such as heparin or chondroitin sulfate
without chemical or physical activation of the collagen.
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