Biomedical Engineering Reference
In-Depth Information
2008b), considering proteins (Pr), polysaccharides (PS), and hydrocarbon-like compounds
(HC) which represent mainly lipids in biological systems. The novelty here is to take silane
(Sl) into account in addition to the three classes of biochemical compounds; the chemical
composition and density considered for these model compounds are listed in Table 3.
Accordingly, the proportion of carbon atoms due to each model compound X (
C
X
/C
tot
) can
be computed by solving the following system of equations:
(N
tot
- Si
org
)/C
tot
= 0.273
×
(C
Pr
/C
tot
)
(4)
O
org
/ C
tot
= 0.312
×
(C
Pr
/ C
tot
) + 0.833
×
(C
PS
/ C
tot
)
(5)
Si
org
/ C
tot
= 0.333
×
(C
Sl
/ C
tot
)
(6)
1 = (C
Pr
/ C
tot
) + (C
PS
/ C
tot
) + (C
Sl
/ C
tot
) + (C
HC
/ C
tot
)
(7)
0.15
a
0.10
0.05
0.00
0.00
0.05
0.10
0.15
N
tot
/
Σ
org
0.15
0.15
b
c
0.10
0.10
0.05
0.05
0.00
0.00
0.00
0.05
0.10
0.15
0.00
0.05
0.10
0.15
N
400
/
Σ
org
(N
tot
-Si
org
) /
Σ
org
Fig. 9. Relations between molar concentrations ratioed to the sum of organic elements (Σorg)
measured by XPS at θ = 0° (data from Table 2) on native (open symbols) or silanized
stainless steel (closed symbols), as such (
¡
,
) or further treated with coupling agent BS
(
S
,
U
), glucose oxidase (
z
,
{
) or coupling agent followed by glucose oxidase (
,
).The
dashed lines represent a
y/x
ratio of 1:1.