Biology Reference
In-Depth Information
vitro
applications. Most popular biosensortransductions are optical
[13], piezoelectrical [14], and electrochemical [15] techniques.
Thebasicschemeofabiosensordeviceisbasedonabiochemical
recognition surface, a physicochemical transducer, and a data
analyse equipment. When performing an analysis, biological sam-
ples that specifically interact with its substrates on the surface are
detected by the recognition surface. The results of the interaction
should form changes which can be physical or chemical. After
recognition,thedetectionsignalsareconvertedtoanothersignalby
thetransducerthatcanbeanalyzedeasily.Thetransformedsignalis
amplified andprocessed for user analysis.
The first biosensor was based on an enzyme electrode and
developed for glucose analysis in 1962 [16]. Then many researches
have focused on biosensing systems. This is mostly due to the
biosensor's high selectivity and sensitivity [17]. In 1975, Divis
proposedmicroorganismelectrodefordeterminingthealcohollevel
in a solution [18]. Also, same year the first glucose biosensor was
produced commercially by Yellow Springs Instruments.
13.2.1
Nucleic Acid Hybridization Biosensors
Nucleic acid is a biosensor which integrates nucleic acid hybridiza-
tion recognition with a signal transducer. Figure 13.1 is a schematic
representation of a nucleicacid biosensor.
The nucleic acid recognition part selectively detects a specific
gene sequence of DNA. A DNA hybridization biosensor uses a DNA
strand of known sequence as a probe of a target DNA sample.
In the last decade there has been a considerable interest in DNA
biosensors due to its significant analytical properties. The most
popular application of DNA biosensors is based on nucleic acid
hybridizationdetection of specific DNAsequences [19].
Such biosensors have many potential applications — for exam-
ple, identification of genes that are implicated in inherited diseases,
single nucleotide polymorphisms (SNP), and some mutations that
play a major role in causing diseases [20-21], identification of
pathogenicmicroorganismswhichareresponsibleforinfectiousdis-
eases [22-23], transgenic organisms for food quality [24], detection
