Biomedical Engineering Reference
In-Depth Information
It is therefore possible to prevent cell proliferation or improve it by
varying the proportions of the functional groups SO
3
-
and COO
-
present on a surface. These polymers displaying anionic groups are
not cytotoxic, but they can be “cytostatic” for certain defined
compositions and towards certain cell lines which can be interesting
for the development of IOLs [HEL 05, YAM 05] able to prevent
secondary cataracts (collaboration with Pr JM Legeais - Hôtel Dieu).
On the other hand, it is important to note that for particular chemical
compositions they can improve osteoblastic differentiation [ANA 05].
b)
The modulation of bacterial adhesion
: the results obtained for
eukaryotic cells and the importance of the selectivity of the protein
response in the cell behavior have naturally led to the study of the
bacterial response induced by these functionalized surfaces. The main
reasons are as follows:
- P. Vaudaux has shown that heparin and dextran when
functionalized by SO
4
2-
and/or COO
-
groups displayed inhibiting
properties of bacterial adhesion. He also showed the importance and
the major role of Fn in the adhesion of
S. aureus
on surfaces such as
PMMA and titanium (Ti) [SIN 99, FRA 99, FRA 00, FRA 97];
- PMMA and PVC surfaces functionalized by SO
3
-
and/or COO
-
groups can be qualified as “heparin-like” or “glycosaminoglycan-like”
since they exhibit anionic groups such as SO
3
-
and/or COO
-
that
are
present in the heparin molecule and in glycosaminoglycan.
The adsorption of Fn on PMMA surfaces functionalized by the
SO
3
-
and/or COO
-
groups leads to a modulation of the
Fn conformation, which is the cause of the modulation of the cell
response through possible interactions or non-interactions with the
α
1 integrins. In the case of bacteria, the cell receptors involved are
“adhesins” (membrane receptors of specific bacteria of binding
proteins such as Fn); if the Fn/adhesin interactions are blocked, then
bacterial adhesion can be inhibited [BER 02, LAT 03].
β
5
The challenge was to show that the SO
3
-
and/or COO
-
groups
present and immobilized at the surface of the “bioactive” polymers
(functionalized PMMA and PVC) were capable of causing the same
