Biology Reference
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Thermoresponsive chitosan/glycerophosphate salt hydrogel coated with
poly- D -lysine immobilized via azidoaniline photocoupling improves cell
adhesion and morphology and neurite outgrowth compared with uncoated
chitosan/glycerophosphate salt hydrogel ( Crompton et al., 2007 ). Increasing
poly- D -lysine concentration did not alter cell survival but significantly
inhibited neurite outgrowth ( Crompton et al., 2007 ).
Laminin is an 180-KDa glycoprotein that plays an important role in neuro-
nal cell adhesion, differentiation, and neurite outgrowth ( Madison, da Silva,
Dikkes, Sidman, & Chiu, 1987; Manthorpe et al., 1983 ). Two peptides of
the lamin-1 molecule, namely, YIGSR (Tyr-Ile-Gly-Ser-Arg) and IKVAV
(Ile-Lys-Val-Ala-Val) sequences, mediate receptor-specific neural cell
adhesion and are known to promote cell adhesion and neurite outgrowth,
respectively ( Graf et al., 1987; Kleinman et al., 1988; Pierschbacher &
Ruoslahti, 1984; Sephel, Burrous, & Kleinman, 1989; Tashiro et al., 1989 ).
Moreover, these domains enhance SC migration. Surface modification of a
biomaterial may improve its biocompatibility. Matsuda et al. developed a
new biomaterial consisting of molecularly aligned chitosan with IKVAV and
YIGSRpeptides bonded covalently. Briefly, chitosanwas thiolated by reacting
4-thiobutyrolactonewith the chitosan amino group and thiol groupof cysteine
located at the endof the synthetic laminin peptides thatwere reactedchemically
with thiolated chitosan to form chitosan- S - S -laminin peptide ( Matsuda,
Kobayashi, Itoh, Kataoka, & Tanaka, 2005 ).
A novel chitosan gel has been synthesized by reaction of chitosan amine
group with methacrylic anhydride, resulting in methacrylamide chitosan
( Yu, Kazazian, & Shoichet, 2007 ). Maleimide-terminated cell adhesive pep-
tides, mi-GDPGYIGSR and mi-GQASSIKVAV, have been coupled to a
thiolated form of methacrylamide chitosan, resulting in increased neuronal
adhesion and neurite outgrowth ( Yu et al., 2007 ).
Synthetic surface modification methods often lead to alterations of the
original material's physical proprieties. The plasma surface modification pro-
cess has been shown to be able tomodify the surface properties of a biomaterial
without affecting its bulk physical properties ( Yeh, Iriyama, Matsuzawa,
Hanson, & Yasuda, 1988 ). Compared with the conventional chemical
method, the percentage of laminin incorporated on chitosan films by plasma
treatment is significantly higher ( Huang, Huang, Huang, & Chen, 2007 ).
Moreover, laminin-modified chitosan membrane significantly increases SC
adhesion ( Huang et al., 2007 ). Carbon nanotube/chitosan fibers coated with
laminin, via an oxygen plasma technique, allowed PC12 cell adhesion,
growth, and guided oriented neurite outgrowth ( Huang et al., 2011 ).
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