Biology Reference
In-Depth Information
Gliosarcoma cells (9 L) and primary neurons have been cultured on
chitosan, GA-cross-linked chitosan, GA-cross-linked chitosan-gelatin con-
jugate, a chitosan-gelatin mixture, chitosan coated with poly-
L
-lysine,
chitosan coated with laminin, and chitosan coated with serum revealed that
coated chitosan, especially chitosan coated with laminin, has excellent nerve
cell affinity, promoted better cell adhesion, spread, and growth in compar-
ison with cross-linked-chitosan or chitosan alone (
Haipeng et al., 2000
).
In conclusion, it was shown that chitosan precoated with ECM
molecules, in particular laminin, improves nerve cell affinity. The ECM
molecules adsorbed on the materials, and the physicochemical properties
of the material improve the adhesion and spread of nerve cells on the
biomaterials.
2.4. Chitosan as a tool for neurotrophic factor delivery
To enhance axonal regeneration, spatial and temporal delivery of therapeu-
tic molecules combined with biomaterials may be helpful. Current methods
for therapeutic agent delivery, such as oral and intravenous administration,
are inadequate for local delivery as they have limitation of dose control, pre-
mature drug degradation, not specific action, and may lead to undesirable
side-effects and/or system effects.
In order to provide a system for local and sustained growth factor release,
poly-lactide-
co
-glycide microspheres have been incorporated into chitosan
guidance channels by spin-coating the interior of a chitosan channel with a
chitosan solution containing microspheres minimizing the exposure of
PLGA microspheres to acidic solution (
Kim, Tator, & Shoichet, 2008
).
Alkaline phosphatase, used as a model protein to test the release and bioac-
tivity, showed high encapsulation efficiency and bioactivity profile over a
90-day period
in vitro
(
Kim et al., 2008
).
Poly-lactide-
co
-glycide microspheres have been physically entrapped in
between two concentric tubes consisting of a chitosan inner tube and a chi-
tin outer tube (
Goraltchouk, Scanga, Morshead, & Shoichet, 2006
). Bovine
serum albumin (BSA), used as a model drug, was released up to 84 days after
encapsulation in the microspheres (
Goraltchouk et al., 2006
). Epidermal
growth factor (EGF), coencapsulated with BSA, was released for 56 days
with a similar profile to that of BSA and was found to be active up to 14 days
(
Goraltchouk et al., 2006
).
Moreover, microstructured polymer filaments used as a nerve implant
have been successfully loaded with chitosan/siRNA nanoparticles
to
