Biomedical Engineering Reference
In-Depth Information
mechanical requirements of the upper ADT. Important progress in biomaterial
research of the last years was made in the improvement of cell adhesion and
proliferation by the optimization of scaffold design with respect to specifi c require-
ments of the different implantation sites
in vivo
[126] . Main aspects of the research
work were focused on the infl uence of different macroscopical and microscopical
design parameters on the local differentiation of variable cells. Other aspects dealt
with the controlled release of growth factors [127, 128]. Until now, relatively little
is known about the infl uence of different surface topographies of polymeric
implant materials on the gene expression and synthesis of enzymes that are
directly involved in extracellular matrix remodeling [129, 130].
Our own results demonstrated the importance of the surface structure of poly-
meric implant materials on the cellular behavior depending on surface roughness
(smooth versus rough surfaces). The cell adhesion, proliferation, as well as the
kinetics of secretion and activity of MMP- 1, MMP - 2 - , and TIMPs differed signifi -
cantly depending on the type of cells and on the surface structure of the copolymer.
Signifi cantly greater average total cell numbers of oral and pharyngeal primary
cells were found after cell seeding on the rough surface compared to the smooth
polymer surface. Esophageal cells showed the highest cell numbers on the control
(polystyrene). Oral and pharyngeal cells revealed similar kinetics of appearance
and activity of MMP-1, MMP-2, and TIMPs with the highest values on Day 1, fol-
lowed by a decrease of the activity levels on the rough polymer and the control
surface. Oral and pharyngeal cells seeded on the smooth polymer surface displayed
an opposite pattern with the lowest activity of MMP-1, MMP-2, and TIMPs on Day
1 and the highest values on Day 12. Esophageal primary cell cultures showed a
comparable kinetic pattern of appearance and activities on all three different sur-
faces (smooth and rough polymer surface, control surface) with the lowest MMP-
1 - , MMP-2, - and TIMP expression on Day 1 and the highest values on Day 12 [131].
The presence or absence of the extracellular matrix or components of it govern
the proliferation, differentiation, and biochemical activities of different primary
cell cultures of the upper ADT. These results were confi rmed by data from the
literature, which also showed the infl uence of the surface topography on the gene
expression and synthesis of the enzymes directly involved in extracellular matrix
remodeling [132] .
The results of these experiments suggest a specifi c infl uence of surface topog-
raphy on the behavior of cells in contact with implant materials. The knowledge
of the exact mechanisms of the cell-biomaterial interactions is a basic requirement
for the development of an “ideal” implant material to establish cell- and tissue-
optimized novel therapeutical options in head and neck surgery based on poly-
meric implant materials.
13.3.4
Application of New Implant Materials in Animal Models
The use of degradable implant materials in the area of the upper ADT makes high
demands on the chemical, enzymatic, bacterial, and mechanical stability of a mate-
rial. A premature degradation of the implant material would probably cause exten-
