Coating of Material Surfaces with Layer-by- Layer Assembled Polyelectrolyte Films - Biological and Biomedical Coatings: Processing and Characterization - page 359

factors embedded in films can provide both a new functionality and a way to adjust cell
differentiation. The first studies concerning the beneficial effect of various proteins and
growth factors have been presented (Section 8.4.3). Very interestingly, in all the works
reported above, the bioactivity of the proteins or growth factors was always preserved. This
indicates that the films are a good nano- and microenvironment for allowing an adequate
preservation of the protein bioactivity, which is often a major concern when the bioactive
moiety is grafted onto an underlying substrate. Thus, the very simple strategy of bioactive
protein adsorption (physisorption) proves to be efficient when applied to PEM films.

(a) (a)'

Acc.V Spot Magn Det WD 20 µm 50 µm

Acc.V Spot Magn Det WD

12.0 kV 4.0 800 × SE 9.7 fil 4a nu 12.0 kV 3.0 428 × SE 9.5 fil 3a

(b) (b)'

Acc.V Spot Magn Det WD 10 µm Acc.V Spot Magn Det WD 10 µm

10.0 kV 3.0 3200 × SE 8.9 Stain Steel bare

10.0 kV 3.0 3200 × SE 8.6 Stain steel + film

(c) (c)'

Acc.V Spot Magn Det WD 10 µm Acc.V Spot Magn Det WD 10 µm

10.0 kV 3.0 3200 × SE 8.5 Nickel Titane bare 10.0 kV 3.0 3200 × SE 8.8 Nickel Titane + film

FIGURE 8.11
Coating of materials used in vascular engineering by LbL films made of PLL and HA. Scanning electron micro-
scope images of bare materials (a, b, c) and of cross-linked (PLL/HA) 24 film coated materials (a′, b′, c'): (a, a′)
polyethylene terephtalate; (b, b′) stainless steel; (c, c′) nickel-titanium alloy. (Scale bar: 20 μm (a), 50 μm (a′), and
10 μm for all other images.)