Biomedical Engineering Reference
In-Depth Information
bio-receptor, enzyme biosensor and glucose oxidase sensor that is using
the specii c name of the enzyme biomaterial.
DNA biosensor exploits the specii city, versatility, excellent selectivity
and reactivity of deoxyribonucleic acid (DNA) in a very co-relative way.
It converts the Watson-Crick base pair recognition event into a readable
analytical signal by its specii c trends. A basic DNA biosensor is designed
and assisted by the immobilisation of a single stranded oligonucleotide
(probe) on a surface of transducer to recognize its complementary (target)
DNA sequences via hybridisation or using the DNA probe to detect other
analytes such carcinogens, drugs, mutagenic pollutants, etc. with binding
ai nities for the specii c structure of DNA sequencing. h e DNA duplex
which is formed on the surface of electrode is known as a hybrid [48].
With the help of electrochemical transducer, these events are converted
into an analytical signal and are referred to as Electrochemical DNA
Biosensors [49].
Millan and Mikkelesen in 1993 was the i rst to give the concept of
electrochemical DNA biosensors [50] by using tris(2,2'- bipyridyl)
cobalt(III),Co(bpy)
3
3+
as an electro-active intercalator. h e use of nucleic
acids as a tool in the recognition and monitoring of many compounds of
analytical interest has been increased signii cantly in few year. h eenzymes
counterpart which is a catalyst has the class of ai nity biosensor belonging
to EBD. Electrochemical biosensors are becoming more preferable than
other transduction method because of such aspect:
A. Low cost and direct signal measurement: Since the 'natu-
ral' and realistic signal during hybridisation is electronic in
nature, the EDB lends itself to direct measurement using the
low cost electrochemical equipment in biosensor.
B. Ease of miniaturisation: h e ease and possibilities and ei -
ciency of producing dif erent kinds of electrodes through
advances microelectronics that allows downscale of EDB
to smaller size - miniaturisation and i nally it's of great
importance.
Electrochemical impedance spectroscopy (EIS) has provided the
detailed information on interfacial kinetics as it is related to the capaci-
tance and electron transfer resistance changes or changes in electrical
properties resembling at the modii ed surface of electrode. h us EIS is
more suitable and stable for the ai nity biosensor. EIS signals are some-
times used as label free EDSs are called impedimetric biosensors [51].
Modelling of DNA or DNA hybridisation kinetics is being studied with
