3 Aptamer-Based Point of Care Testing Schemes
63
NTH-based aptamer probe, thus releasing DS nanoprobes from the SPGE, giving
out a low peak current. This method showed high sensitivity and selectivity toward
HepG2 with LOD of 5 cells mL
−1 [59].
In addition to the usual methods of DNA origami-based biosensors, such as
electrochemical or optical, modern and sophisticated sensor techniques like DNA
origami nanopores have been developed. They can be used as a new tool in the field
of biosensors, especially when combined with aptamers. Generally, DNA origamibased aptasensors are more sensitive compared with other sensors, but they are
composed of multiple sequences, increasing the cost of their synthesis and this could
be considered as a limitation for DNA origami-based aptasensors.
3.3.4 Capacitive Aptasensors
Capacitive biosensors belong to the affinity biosensor group, which operates by
registering a direct bond between the sensor surface and the target molecule [60].
This type of biosensors measures the changes in dielectric properties and thickness
of the dielectric layer at the electrolyte/electrode interface. Capacitive sensors of a
minimum size can be made using materials such as metal oxides, copper, tin and
other metals that can conduct the flow.
Using DNA aptamers on a capacitive biosensor, the rapid detection of nicotinamide phosphoribosyl transferase was demonstrated with human samples [61].
Sensitivity was improved to 240 times higher than SPR detection levels with the
use of capacitive frequency. Studies from Qureshi et al. have shown the detection of C-reactive protein, a cardiac biomarker using aptamer and detection of
vascular endothelial growth factor by aptamer-antibody sandwich on capacitive
biosensor [62].
The capacitive aptasensor developed by [63] is a highly reliable, a tiny sensor suitable for POCT, with suitable characteristics such as low sample usage, fast response
time and easy operation. Touch screen technologies are further add-ons. Zhurauski
et al. developed an interdigital electrode-based capacitive biosensor platform for
the identification and estimation of HER4, a protein tumor biomarker, in undiluted
serum. The sensor delivered high sensitivity with a broad dynamic range from 1 pM to
100 nM and a LOD of lower than 1 pM [64]. Arya et al. designed a thiol aptamer functionalized capacitive aptasensor for specific detection of human epidermal growth
factor receptor 2 (HER2), a biomarker for breast cancer, in undiluted serum with
LOD of lower than 1 pM [65].
3.3.5 Smartphone Enabled Aptasensors
The smartphone-based detection of biomolecules is one of the ideal systems for the
use of the biosensor outside the laboratory, and it will have a large impact on society.
63
NTH-based aptamer probe, thus releasing DS nanoprobes from the SPGE, giving
out a low peak current. This method showed high sensitivity and selectivity toward
HepG2 with LOD of 5 cells mL
−1 [59].
In addition to the usual methods of DNA origami-based biosensors, such as
electrochemical or optical, modern and sophisticated sensor techniques like DNA
origami nanopores have been developed. They can be used as a new tool in the field
of biosensors, especially when combined with aptamers. Generally, DNA origamibased aptasensors are more sensitive compared with other sensors, but they are
composed of multiple sequences, increasing the cost of their synthesis and this could
be considered as a limitation for DNA origami-based aptasensors.
3.3.4 Capacitive Aptasensors
Capacitive biosensors belong to the affinity biosensor group, which operates by
registering a direct bond between the sensor surface and the target molecule [60].
This type of biosensors measures the changes in dielectric properties and thickness
of the dielectric layer at the electrolyte/electrode interface. Capacitive sensors of a
minimum size can be made using materials such as metal oxides, copper, tin and
other metals that can conduct the flow.
Using DNA aptamers on a capacitive biosensor, the rapid detection of nicotinamide phosphoribosyl transferase was demonstrated with human samples [61].
Sensitivity was improved to 240 times higher than SPR detection levels with the
use of capacitive frequency. Studies from Qureshi et al. have shown the detection of C-reactive protein, a cardiac biomarker using aptamer and detection of
vascular endothelial growth factor by aptamer-antibody sandwich on capacitive
biosensor [62].
The capacitive aptasensor developed by [63] is a highly reliable, a tiny sensor suitable for POCT, with suitable characteristics such as low sample usage, fast response
time and easy operation. Touch screen technologies are further add-ons. Zhurauski
et al. developed an interdigital electrode-based capacitive biosensor platform for
the identification and estimation of HER4, a protein tumor biomarker, in undiluted
serum. The sensor delivered high sensitivity with a broad dynamic range from 1 pM to
100 nM and a LOD of lower than 1 pM [64]. Arya et al. designed a thiol aptamer functionalized capacitive aptasensor for specific detection of human epidermal growth
factor receptor 2 (HER2), a biomarker for breast cancer, in undiluted serum with
LOD of lower than 1 pM [65].
3.3.5 Smartphone Enabled Aptasensors
The smartphone-based detection of biomolecules is one of the ideal systems for the
use of the biosensor outside the laboratory, and it will have a large impact on society.