Modifying Vascular Prosthesis Materials
to Enhance Endothelial cell adhesion
Dr T Markkula
The talk focused on vascular grafts, which
are replacements for blood vessels. Materials considered
were PET and PTFE. The grafts are not always stable and
the adhesion of the endothelial cells on implanted structures
can be weak. The surface layer of the polymer host material
needs to be modified such that cell adhesion is maintained
in real environments. The adhesion is in three regions,
the cell and the surface, cell to cell and cell to external
macro-phages, which flow onto the surface. These interactions
are studied using XPS, SSIMS, AFM and using contact angle
measurements.
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Dr T Markkula
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Using different plasma gases,
CAM measurements indicate that the surface wetting ability
of the standard polymeric host materials (PET,PTFE) and
be altered. Using ammonia and nitrogen, it is possible to
dramatically reduce the surface Fluorine level and force
generation of O and N based species in the surface layer.
This treatment alters the polymer/cell adhesion. The cell/polymer
adhesion can be estimated by growing cultures on the treated
surfaces and then doing flow experiments on the samples,
counting the cells before and after the flow experiment.
Improving the cell/cell adhesion can be
increased by using adhesion promoters which should bond
to the endothelial and enhance cell/cell adhesion and cell/polymer
adhesion. The effects are again studied using flow experiments
and by counting the number of bonded cells. In the case
of some of the plasma surface treated substrates, the adhesion
promoters do not enhance the cell adhesion to the treated
substrate. However, with the ammonia plasma treated substrates,
the adhesion promoters can further enhance the cell adhesion
to the host material.
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