Biomedical Engineering Reference
In-Depth Information
13.2.6.2
Determination of Mb Concentration [37]
h e quantity of Mb in biological liquids (blood, urine) can tell us about
series of human illnesses, for example: ischemia, infarction, some meta-
bolic disturbance.
h e technical aspects were the same as it was described above at the
determination of anti-insulin Ab. But in this case a freshly prepared gold
surfaces were modii ed with the thioglycolic acid anilid - C
8
H
9
ONS (short
molecule) and the dodecanethiol - HS(CH
2
)
11
CH
3
(long chain molecule),
which dif er in length of the hydrocarbon chains and nature of the tail
groups. Chemisorption was performed by 15 h immersion of gold i lms in
1mM ethanol solution at room temperature, followed by thorough rinsing
with absolute ethanol and drying in a l ow of clean air. h e overall time of
incubation with the biocomponent was no more than 5 min.
It was investigated the binding of the specii c monoclonal Ab with
human, rabbit and badger Mb's. On the surface of transducer the mono-
clonal Ab (with the concentration of 200 μg/ml) were immobilized by the
physical sorption from a solution in a 50 mM PBS, pH 7,4. Unbounded Ab
was displaced by the PBS and then the corresponding Mb with the dif erent
concentration was added. It was shown that the cross reaction of the inter-
action of non-specii c Ab with the any Mb was negligible. h e shit of the
resonant angle was already observed at the injection of 1 ng/ml of appro-
priate Mb to the immobilized monoclonal Ab. h e sensitivity of analysis
was in the range from1ng/ml to 10 μg/ml. h e formed immune complex
did not destroy by PBS washing. Total dissociation of specii c interaction
was achieved at er the injection of the buf er with pH 2,2 into system. At er
that we observed only presence of adsorbed Mb on the surface. h e storage
of the preliminary prepared transducers at room temperature for about 5
day did not deteriorate its sensitivity. h e most appropriate results were
obtained at the thiol-modii ed gold surface application.
h us, there is all reasons for the conclusion that this biosensor may i nd
application as the suitable method of diagnostics of various illnesses based
on the estimation of Mb content in biological liquids.
13.3
Electrochemical Enzymatic Biosensors Based on
the Ion-sensitive Field Ff ect Transistors (ISFETs)
Many types of enzyme biosensors based on the ISFETs were cre-
ated at er the i rst reported work in 1980 [39]. In the comparison
with the other types of biosensors, the ISFET based ones have certain
