Biology Reference
In-Depth Information
G4.0-NH
2
) to obtain a thin film. Single-stranded 3'-biotin end-
labeled oligonucleotide was immobilized onto the film to obtain a
stablerecognitionlayerthroughbiotin-avidincombinationtodetect
complementary target.
4.3 Signal Transduction and Amplification Strategies
Recent literature dealing with integration of Au-NPs with DNA
detectionsystemsshowsthatdifferentstrategiescanbeemployedto
achieve improved analytical performance of the resulting genosen-
sors. As mentioned above, using Au-NPs-modified electrodes, the
amount of DNA immobilized onto the electrode can be considerably
enhanced. The e
cient immobilization of DNA onto the transducer
paves the way for the design of effective signal transduction
approaches of the hybridization event. Furthermore, Au-NPs have
beenemployedasamplificationcomponentswhichwhencombined
with electrochemical techniques have given rise to the design of
selectiveandhighlysensitiveDNAsensors[26].Castaneda
et al.
[27]
and Guo
et al.
[26, 28] have recently reviewed the achievements of
the electrochemical sensing of DNAusing Au-NPs.
In a rather general approach, and in order to systematize the
content of this section, we have considered separately the detection
strategies that take advantage of the design of sensing platforms
integrating Au-NPs, but in which the detection methodology itself
does not involve Au-NPs as an element to obtain the signal trans-
duction, and those involving direct participation of Au-NPs in the
generation of the electroanalytical signals. In the next subsections,
some illustrative examples of each of these methodologies will be
commented, and tables summarizing other recent works using the
different detection strategies willbegiven.
4.3.1
Detection Strategies Not Involving Direct
Participation of Au-NPs in the Generation
of the Electrochemical Signal
The immobilization methods commented in Sec. 4.2 can be
coupled with signal transduction methodologies involving different
