Abstract:
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Considering the structural role of type IV collagen (Col
IV) in the assembly of the basement membrane (BM) and
the perspective of mimicking its organization for vascular
tissue engineering purposes, we studied the adsorption
pattern of this protein on model hydrophilic (clean glass)
and hydrophobic trichloro(octadecyl)silane (ODS) surfaces
known to strongly affect the behavior of other matrix
proteins. The amount of fluorescently labeled Col IV was
quantified showing saturation of the surface for
concentration of the adsorbing solution of about 50μg/ml,
but with approximately twice more adsorbed protein on
ODS. AFM studies revealed a fine – nearly single molecular
size – network arrangement of Col IV on hydrophilic glass,
which turns into a prominent and growing polygonal
network consisting of molecular aggregates on hydrophobic
ODS. The protein layer forms within minutes in a
concentration-dependent manner. We further found that
human umbilical vein endothelial cells (HUVEC) attach
less efficiently to the aggregated Col IV (on ODS), as judged
by the significantly altered cell spreading, focal adhesions
formation and the development of actin cytoskeleton.
Conversely, the immunofluorescence studies for integrins
revealed that the fine Col IV network formed on hydrophilic
substrata is better recognized by the cells via both α1 and
α2 heterodimers which support cellular interaction, apart
from these on hydrophobic ODS where almost no clustering
of integrins was observed. |