416
H. Jin
MPT64 is a 23 kDa secreted protein encoded by Mtb and virulent M. Bovis
strains, it has been constructed with fullerene doped polyaniline (C60-Pan) nanohybrid constructs to obtain ultrasensitive electrochemical MPT64 aptasensors with
LOD of 20 fg mL
−1 [47] or polymer poly (3,4-ethylenedioxythiophene) (PEDOT)
doped with carbon nanotubes to achieve a detection limit of 0.5 ± 0.2 fg mL
−1 only
within 15 min and up to seven times of reusability [48].
IFN-γ is a product of infection stimulation, mainly by macrophages and T
helper cells (CD4 +), which can be used as an evidence for the diagnosis of latent
tuberculosis.
Abnous et al. [49]. constructed A triple-helix molecular switch (THMS)-based
electrochemical aptasensor for IFN-γ using a gold electrode and MB as a redox
probe. Under optimized conditions, the assay has a 3 pg mL
−1 detection limit and
a linear range that extends from 10 to 1500 pg mL
−1 . Another electrochemical
aptasensor for IFN-γ assay, based on a graphene/AuNPs modified electrode coupled
with a dual enzyme-assisted signal amplification was developed with an ultra-low
detection limit of 2 pM while exhibited a wide linear range from 5 pM to 5 nM [50]. In
Li’s work, a low-price and high efficient direct (for multi-sample quantification) and
indirect (for strain identification) dot-blot assays were developed using a ManLAM
specific aptamer for LTBI screening and an android app for processing and sharing
of images taken by a simple smartphone camera in order to comply with portability
requirements [51].
14.3.1.3 Pregnancy and Fertility
Cortisol is the most prominent biomarker related to stress; it plays a key role in the
fight-or-flight situation, alters the immune response, and suppresses the digestive
and the reproductive systems [52]. A significant deviation in the cortisol level from
the normal range in sweat, serum, and saliva is found to be associated with stress
conditions [53–55].
Cortisol is a very small molecule with a size of 362.46 Daltons, and its aptamer
was first selected through a tunable stringent magnetic bead selection strategy [56].
This cortisol aptamer named Aptamer 15-1 was applied in the gold nanoparticle
assay, achieving a detection limit of 150–600 nM. The detection limit corresponds to
the normal range of free cortisol (30–140 ng/mL or 100–500 nM) in human serum.
The aptasensor exhibited remarkable specificity, as it presented no cross reaction
with other stress biomarkers, such as epinephrine and norepinephrine, and was also
non-selective against other structurally similar molecules of cortisol.
Bao et al. [57] developed a cortisol aptamer-based colorimetric assay with gold
nanorod to quantify the level of cortisol using the coordinated aggregation (at 500
mM of NaCl) and dispersion (with 10 μM of aptamer). This aptamer conjugated with
UV-visible spectroscopy colorimetric assay which is an easier visual detection and
reached the limit of detection of cortisol at 0.25 mg/mL, and this method is reliable
to identify the condition of gestational hypertension during the pregnancy period.
H. Jin
MPT64 is a 23 kDa secreted protein encoded by Mtb and virulent M. Bovis
strains, it has been constructed with fullerene doped polyaniline (C60-Pan) nanohybrid constructs to obtain ultrasensitive electrochemical MPT64 aptasensors with
LOD of 20 fg mL
−1 [47] or polymer poly (3,4-ethylenedioxythiophene) (PEDOT)
doped with carbon nanotubes to achieve a detection limit of 0.5 ± 0.2 fg mL
−1 only
within 15 min and up to seven times of reusability [48].
IFN-γ is a product of infection stimulation, mainly by macrophages and T
helper cells (CD4 +), which can be used as an evidence for the diagnosis of latent
tuberculosis.
Abnous et al. [49]. constructed A triple-helix molecular switch (THMS)-based
electrochemical aptasensor for IFN-γ using a gold electrode and MB as a redox
probe. Under optimized conditions, the assay has a 3 pg mL
−1 detection limit and
a linear range that extends from 10 to 1500 pg mL
−1 . Another electrochemical
aptasensor for IFN-γ assay, based on a graphene/AuNPs modified electrode coupled
with a dual enzyme-assisted signal amplification was developed with an ultra-low
detection limit of 2 pM while exhibited a wide linear range from 5 pM to 5 nM [50]. In
Li’s work, a low-price and high efficient direct (for multi-sample quantification) and
indirect (for strain identification) dot-blot assays were developed using a ManLAM
specific aptamer for LTBI screening and an android app for processing and sharing
of images taken by a simple smartphone camera in order to comply with portability
requirements [51].
14.3.1.3 Pregnancy and Fertility
Cortisol is the most prominent biomarker related to stress; it plays a key role in the
fight-or-flight situation, alters the immune response, and suppresses the digestive
and the reproductive systems [52]. A significant deviation in the cortisol level from
the normal range in sweat, serum, and saliva is found to be associated with stress
conditions [53–55].
Cortisol is a very small molecule with a size of 362.46 Daltons, and its aptamer
was first selected through a tunable stringent magnetic bead selection strategy [56].
This cortisol aptamer named Aptamer 15-1 was applied in the gold nanoparticle
assay, achieving a detection limit of 150–600 nM. The detection limit corresponds to
the normal range of free cortisol (30–140 ng/mL or 100–500 nM) in human serum.
The aptasensor exhibited remarkable specificity, as it presented no cross reaction
with other stress biomarkers, such as epinephrine and norepinephrine, and was also
non-selective against other structurally similar molecules of cortisol.
Bao et al. [57] developed a cortisol aptamer-based colorimetric assay with gold
nanorod to quantify the level of cortisol using the coordinated aggregation (at 500
mM of NaCl) and dispersion (with 10 μM of aptamer). This aptamer conjugated with
UV-visible spectroscopy colorimetric assay which is an easier visual detection and
reached the limit of detection of cortisol at 0.25 mg/mL, and this method is reliable
to identify the condition of gestational hypertension during the pregnancy period.