Biology Reference
In-Depth Information
Figure 4.12.
Schematic illustration of DNA conductimetric detection
enhanced by reporter DNA-Au-NP conjugates [71] (reprinted with permis-
sion of Wiley).
On the other hand, a nanoparticle enhancement approach has
been described by Dong
et al.
[71] to improve the detection
sensitivity of field-effect transistors based on single-walled carbon
nanotube networks (SNFETs). Figure 4.12 shows as the target DNA
washybridizedwithprobeDNAonthedevice,reporterDNAlabeled
with Au-NPs flank a segment of the target DNA sequence. The
amplified change in drain current allowed a DNA concentration
down to 100 fM to be detected.
Table 4.5 summarizes recent works which appeared in the
literature on the development of label-free genosensors employing
electrochemical impedance and conductimetry as transduction
techniques.
4.3.2.3 Signal enhancement methods
A useful approach to improve the sensitivity of genosensors
involving the use of Au-NPs consists of performing silver or
even gold precipitation onto immobilized Au-NP-DNA conjugates.
Nevertheless, the achieved improvements seem to be a compromise
