Biomedical Engineering Reference
In-Depth Information
glucose, insulin and anti-insulin Ab level at the control of the diabetic
and autoimmune state.
Amperometrical channel includes whole line of planar microelectrodes
with help of which current was registered. As a rule the average value of
three microelectrodes was preceded. h ermo metrical channel is presented
by thin layer sensors which work in dif erential regime. Output signals of
the integral biosensor are processed by the special electronic block. h in
layer temperature sensors were prepared by two ways: on the basis of plati-
num or oxide cerium.
h ese sensors together with the platinum working electrodes and ref-
erence electrode (AgCl) for the amperometrical measuring were situated
on the common solid phase. h ree working electrodes were taken for the
increasing of accuracy of measurements. h ermo metrical channel con-
tents also working and reference thermistors which have weaving form.
Enzymes as well as Ag or Ab were immobilized on the transducer surface
at er its preliminary treatment by PAA or PSS.
h e integral biosensor contents simultaneously two separate channels:
amperometrical and thermo metrical is presented in Figure 13.7.
It was demonstrated that thermometry allows providing control of
concentrations in frame of 0.002-25; 0.005-100; 0.1-10 mM and sensitiv-
ity about 2.35; 0.45 and 0.85 rel. units/mM for glucose, sucrose and lactate
Protective layer
(AI
2
O
3
)
(
B
)
Pt
Ag
AgCI
Pt
0.1
Sensitive layer
15 mm
Pt
(
C
)
0.05
0.1
0.05
0.05
4.6 mm
(
A
)
1
23 4
5
6
(
D
)
Figure 13.7
Scheme of the microelectronic chip (with concrete materials and structure
dimensions (A), overall view of two parts of the multi-parametrical biosensor:
(B) - electronic unit for the signal registration and (C) - multi-channel block with the
microelectronic registration of the ampero- and thermo metrical signals. (D) - the section
of the biosensor: 1-quartz basis; 2 - layer of AgCl; 3 - silver electrode; 4 - measured
platinum electrodes; 5 platinum thermo resistance; 6 - biochemical structure (additional
explanations in the text).
