Biomedical Engineering Reference
In-Depth Information
(a)
(b)
Film
Silver electrode
Quartz
S-5200 5.0 kV x30.0 k SE
1.00
µ
m
(c)
(d)
FIGURE 10.4
(a) A SEM photo of [(PEI/PSS)
4
+
(PDL/gelatin)
12
] fi lm coated on a silver-electrode resonator
(cross-section view); (b) endothelial cell adhesion on a (PSS/PEI)
8
fi lm at day 3 (100
×
); (c) endothelial cell
adhesion on a [(PSS/PEI)
8
+
PSS] fi lm at day 3 (100
×
); and (d) endothelial cell adhesion on a [(PSS/PEI)
4
+
(gelatin/PDL)
4
). (Reproduced from Ai, H., Lvov, Y.M., Mills, D.K., Jennings, M.,
Alexander, J.S., and Jones, S.A.,
Cell Biochem. Biophys
., 38, 103
-
114, 2003. With permission.)
+
gelatin] fi lm at day 3 (100
×
This suggestion is consistent with studies of LbL assembly as a method for surface modifi cation of
neutral polymer polyethylene terephthalate [75,76].
Few endothelial cells can adhere on silicone rubber substrate. After polyelectrolyte multilayer
fi lm deposition, some cells can attach to fi lms with PSS or PEI outermost layers but very few can
remain on the surface after 3 days (Figures 10.4b and 10.4c). In comparison, a gelatin outermost
layer is friendly for endothelial cell adhesion and growth, and no obvious cytotoxicity was observed
(Figure 10.4d). Cell adhesion density on gelatin increased to 11.7
×
10
4
cm
-2
after 7 days of seeding,
10
4
cm
-
2
) outermost layers. In
another study, a similar fi lm structure with composition of (PSS/PEI)3/(fi
3
fi bronectin/PDL)
4
or (PSS/
PEI)
3
/(laminin/PDL)
4
was highly favorable for neuron cell adhesion; both lactate dehydrogenase
(LDH) assay and fl uorescence cellular metabolism observations demonstrated that the fi lm was bio-
compatible with those cells [59]. LbL self-assembly and other molecular deposition and lithographic
patterning techniques, with nanometer resolution for arranging neuronal-specifi c molecules, may
be useful tools for studying neural cellular communication and signaling [77].
which was much higher than PEI (0.4
×
10
4
cm
-
2
) and PSS (2.3
×
10.2.3 U
LTR ATHIN
C
OATINGS
ON
M
EDICAL
I
MPLANTS
The surface topography and chemistry of a biomaterial are important parameters that infl uence
protein adsorption, cell interaction, and the host response [78]. However, most medical implants
lack a reasonable biointerface between the implant and the surrounding tissues. Local nonspecifi c
