Biology Reference
In-Depth Information
Figure 13.1. Schematic representation of a nucleic acid biosensor. See
also ColorInsert.
of DNA damage caused by drugs, toxins, or radiation [25-26], and
many more clinical applications.
Nucleic acid biosensors can be classified on the basis of
their transduction technology. The transducer converts the nucleic
acid hybridization recognition into a measurable analytical signal
[27-28]. Electrochemical, optical, piezoelectrical, acoustical, and
mechanical transducers are among the many types found in DNA
biosensors.
Optical sensors employ optical fibers or planar waveguides
to direct light to the sensing film. The measured optical signals
oftenincludeabsorbance,fluorescence,chemiluminescence,surface
plasmon resonance (to probe refractive index), or changes in light
reflectivity.ManystudiesonSPRasanopticalmethodforbiosensing
havebeencarriedoutbecausethismethodallowsthemeasurement
of the kinetics of biomolecular interactions in real time with a high
degree of sensitivity without labeling of the biomolecules [29-30],
however, they cannot be easily miniaturized for insertion into the
bloodstream. Most optical methods of transduction still require a
spectrophotometer to detect any changes in signal [31].
Piezoelectric biosensors are mass-sensitive biosensors which
can produce a signal based on the mass of chemicals that interact
with the sensing film. Quartz Crystal Microbalance (QCM) sensorsa
 
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