Biomedical Engineering Reference
In-Depth Information
5.0
4.5
4.0
3.5
3.0
2.5
2.0
*
EO sterilization
LTP sterilization
*
*
1.5
1.0
0.5
0.0
Figure 13.1
Mean rate of cell lysis after
different sterilization techniques. Mean rate of
cell lysis after EO and LTP sterilization of the
polymer samples and different incubation
time in physiological solution (MEM).
Statistically signifi cant differences of the mean
rates of cell lysis were found for the differently
sterilized samples without MEM incubation,
as well as after 2 and 4 weeks of incubation
with MEM. Abbreviations: EO
=
ethylene -
oxide sterilization, LTP
=
low - temperature
plasma sterilization, MEM
=
minimal
essential medium. Reprinted with permission
from [20]. Copyright 2003 Wiley Periodicals,
Inc.
have a considerably lower thermal and chemical stability as ceramic or metallic
materials. They are generally not sterilized with conventional sterilization methods
like heat sterilization (temperatures between 160 and 190 °C) or steam sterilization
(121 and 134 °C) to avoid a damage of polymers. Sterilization applying ionizing
irradiation can change the chemical structure of polymers either by chain degrada-
tion or by new crosslinking of chains, so that surface characteristics as well as
thermal and mechanical bulk properties can be strongly infl uenced [18]. A change
of the chemical surface structure of implant materials can infl uence their biocom-
patibility
in vitro
and
in vivo
[19]. Since the sterilization of polymer-based bioma-
terials makes high demands on the sterilization method, low- temperature
sterilization methods like plasma sterilization (low-temperature plasma steriliza-
tion) and sterilization with ethylene oxide are in the focus of intensive contempo-
rary research [20 - 23] (Figure 13.1 ).
13.2
Regenerative Medicine for the Reconstruction of the Upper Aerodigestive Tract
Head and neck surgery is concerned with the reconstruction of damaged local
tissues like mucosa, cartilage, bone, or skin due to congenital anomalies, progres-
sive diseases, as well as therapeutical interventions. Fistulae of different genesis
are associated with most serious complications in the head and neck area [24-26].
