Biology Reference
In-Depth Information
Figure 4.16.
Schematic outline of the label-free impedimetric biosensor
for thrombin at an aptamer-functionalized Au electrode based on a three-
level cascaded signal amplification: (a) Formation of a mixed monolayer
of thiolated aptamer and 6-mercaptohexanol on the AuE; (b) thrombin
addition and binding with aptamer; (c) binding with Apt-Au-NPs to
carry out the first-level signal amplification (I); (d) the enlargement of
the SDS-stabilized Apt-Au-NPs to achieve the second/third-level signal
amplification (II/III); and (e) schematic outline of the electron-transfer
resistance of different modified electrodes [82] (reprinted with permission
of acs).
leading to an enhancement of electron-transfer resistance and
achieving the third-level signal amplification. The label-free electro-
chemical impedimetric developed aptasensor showed a detection
range from 100 fM to 100 nM and could provide a promising
model for electrochemical impedance spectroscopy detection of
proteins.
Similarly to previous detection approaches, recent works on the
developmentofDNAelectrochemicalbiosensorsbasedontheuseof
Au-NPsandsignalenhancementmethodstoimprovethesensitivity,
are summarized in Table4.6.
