Biomedical Engineering Reference
In-Depth Information
OH
O
O
HOH
2
C
HOH
2
C
NH
2
NH
(
a
)
O
O
O
O
O
+
O
O
O
O
O
O
HO
O
HO
O
NH
NH
2
HOH
2
C
HOH
2
C
O
O
OH
HOOCH
2
COH
2
C
HOOCH
2
COH
2
C
(
b
)
O
O
O
O
O
+
O
O
HO
O
HO
O
NH
2
NH
O
O
OH
O
HN
O
C
NH
2
HOH
2
C
HOH
2
C
NH
O
O
(
c
)
O
O
O
O
+
N
O
O
C
O
HO
O
O
HO
O
HN
HOH
2
C
HOH
2
C
NH
2
C
O
HN
O
Figure 11.15
Preparation of a visible light-curable (a) furfurylated low molecular
weight chitosan and (b) a furfurylated low molecular weight O-carboxymethyl
chitosan derivative. (c) Preparation of low molecular weight chitosan introduced
with a furfuryl isocyanate derivative.
also increased in proportion to the exposure time to visible light and with
higher concentrations. It is important to determine how long the cross-
linked gel fi lm can be maintained. A solution of furfurylated chitosan
and Rose Bengal was irradiated with visible light for 3 min and kept in
phosphate-buffered saline at 37
C, and the crosslinking ratio was mea-
sured every 24 h. After 5 days, the amount of remaining fi lm decreased
to 60%; it decreased continuously in volume over 1 week and completely
dissolved after 2 weeks. Generally, wound healing requires 4-5 days, so
the furfurylated chitosan and Rose Bengal system is considered suitable
for preventing adhesions in wound treatment.
In vitro
cell attachment and viability tests revealed that furfurylated chi-
tosan derivatives had no effect on cell behavior, but the photocured mate-
rials had a signifi cant inhibitory effect on cell adhesion. These properties
might play an important role when they are applied as an anti-adhesive
agent or as a wound-dressing material. Because a hydrophobic surface
was formed by solidifi cation of furfurylated chitosan systems, interactions
between the solidifi ed gel and cells is reduced. An anti-adhesive agent is
desirable to act as a kind of barrier for tissues subjected to surgery and
helps keep them separate from neighboring tissues. The reduced interac-
tion of the visible light-cured chitosan gel with cells is important to reduce
side effects when it is used in such applications.
°
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