Advances in biosensors: principle, architecture and applications

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order to achieve this, an immobilized ssDNA is used as probe in bioreceptor which the base
sequence is complementary to the target of interest. Exposure of target to the probe which
results in hybridization of complementary ssDNA to form dsDNA will result in producing
biochemical reaction that allows transducer amplified the signal into electrical one.
Subsequently, literature shows that the present of some linker such as thiol or biotin is needed
in the effort to immobilize the ssDNA onto the sensing surface (Cagnin et al. 2009, Larzerges
et al. 2012). An important property of DNA is that the nucleic acid ligands can be denatured
to reverse binding and the regenerated by controlling buffer ion concentration (Parkinson and
Pejcic 2005). The nucleic acid biological recognition layer which incorporates with transducer
is easily synthesizable, highly specific and reusable after thermal melting o the DNA duplex
(Teles and Fonseca 2008). In addition, this biosensor possesses a remarkable specificity to
provide analytical tools that can measure the presence of a single molecule species in a
complex mixture (Brett 2005). DNA based biosensor has potential application in clinical
diagnostic for virus and disease detection (Chua et al. 2011, Lui C. 2009, Thuy et al. 2012).
Moreover, Yeh et al. 2012 recently has reported optical biochip for bacteria detection based
on DNA hybridization with detection limit of 8.25 ng/ml. However, electrochemical
transduction is most abandon method used to studying DNA damage and interaction which
reported in literature. The development of electrochemical DNA biosensor has received a
great deal of attention lately and this has largely been driven by the need to developed rapid
response, high sensitivity, good selectivity and experimental convenience (Liu A. et al. 2012).
Cell based sensor
Cell based sensor are the type of biosensor, which use living cell as the biospecific sensing
element and are based on the ability of living cell to detect the intracellular and extracellular
microenvironment condition, physiological parameter and produces response through the
interaction between stimulus and cell (Wang and Liu 2010). Microorganisms such as bacteria
and fungi can be used as biosensors to detect specific molecules or the overall ‘‘state’’ of the
surrounding environment (Acha et al. 2010). Furthermore, proteins that are present in cells
can also be used as bioreceptors for the detection of specific analyte (Acha et al. 2010).
Essentially, living cell based biosensor is a unique biosensor in contrast to other type of
biosensor that contains materials that extracted from living things. These types of biosensor
has leveraged of pros and cons. The detection limit of this biosensor is mainly determined by
the natural environmental conditions in which the cell can stay alive for long period where
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