Biomedical Engineering Reference
In-Depth Information
B
A
bR
V
2
bR-doped
lipid membrane
R
p
I
(
t
)
p
V
1
component X
X
Figure 16. A. Electrochemical model of a bR-containing membrane coupled to a
second electrochemically active component X. The light-induced activity of the
proton pump bR generates a potential difference
V
p
=
V
2
=
V
1
under short-circuit
conditions. B. Theoretical model of the electrochemical system shown in A. The
network comprises a resistance
R
p
and a capacitance
C
p
to account for the proper-
ties of the bR-doped lipid membrane. In parallel, the proton pump activity is sym-
bolised by the current source
I
p
(
t
). X describes a coupled electrochemically active
component.
In this case, the electrical conductance
G
and capacitance
C
of
both, the purple membranes,
G
p
and
C
p
as well as the ones of the
nano-BLMs,
G
m
and
C
m
impact the pump current
I
p
. In combina-
tion with Eq. (8), a differential equation for the voltage
V
p
can be
written (Eq. 9):
§
V
·
x
x
p
¨
©
¸
¹
I
1
V
G
V
G
V
C
V
C
(9)
p,0
p
m
p
p
p
m
p
p
*
V
The solution of the differential equation yields an expression for
V
p
(
t
). To obtain the measured photocurrent
I
(
t
), Eq. (10) needs to
be employed:
x
I
t
V
C
V
G
(10)
p
m
p
m
For
t
t
on
, Eqs. (9) and (10) yield:
Search WWH ::
Custom Search