11 Hormone Aptamers in Endocrine-Related Diseases
335
for positive immunostaining. Recently Rajesh Ahirwar et al. [63] fabricated an electrochemical (voltammetric) aptasensor for accurate and rapid quantification of ERα
in breast tissue lysates. Researchers collected human breast tissues from cancerous
and normal people, respectively. They analyzed the tissue extract for the Erα through
conventional ELISA and aptamer-assisted ELISA methods. Both methods acquired
similar results. The aptasensor measures the change in electron flow caused by the
structural change of the aptamer from unbound state to target-bound state. The electrical signal changes with the target concentration proportionally, so it can accurately
and quickly detect ERα in breast tissue lysates quantitatively. The method of electrochemical aptasensor to measure ERα is compared with other existing ERα detection
schemes, which demonstrates the feasibility of aptasensor for disease diagnosis.
However, the research still needs a considerable sample size to further strengthen the
clinical potential of this aptasensor.
11.3.1.2 Aptamer Used in Pregnancy Diagnosis
Aptamers can also be used in pregnancy diagnosis. In the early stage of pregnancy, P4 can be used as an important detection indicator. Estrogens drive pubertal
development, whereas P4 is the major stimulus for cell proliferation in the adult
mammary gland [64]. Zhu [65] has developed an antibody-aptamer sandwich
cathodic photoelectrochemical biosensor for the detection of P4, which has already
been successfully applied in the determination of P4 in human serum samples.
Early in pregnancy, the body releases large amounts of human chorionic
gonadotropin, a hormone that plays a key role in the maintenance of pregnancy
and a baby’s development. Human chorionic gonadotropin (hCG) is synthesized by
syncytiotrophoblast in the placenta [66]. During the first six weeks of pregnancy, the
ovaries are transformed into gestational luteum after ovulation, and hCG promotes
the secretion of progesterone, estradiol, and estrone [67]. The abnormally high or low
values could also be associated with adverse pregnancy outcomes. The level of hCG
can monitor pregnancy and pregnancy-related disorders. Scientists have developed
hCG-related aptamers and fabricated corresponding biosensors. In 2013, Ding [68]
developed an hCG-binding peptide aptamer to detect aptamer. In contrast to other
detecting methods, this detecting method doesn’t rely on the use of antibody, so it
is more stable and owns better biocompatibility to the inner environment. Xiaokang
Ding identified oligopeptide sequences by use of phage libraries. They selected a
specific phage library against immobilized hand translated their DNA sequences to
oligopeptide sequences. The selected oligopeptide binds to hCG specifically with a
dissociation constant of 0.9 nM. According to Xiaokang Ding’s achievement, Xia
et al. [69] developed a graphene oxide (GO)-based fluorescent platform for the detection of hCG in 2016. They employed a fluorescein isothiocyanate (FITC)-labeled
hCG-specific binding peptide aptamer as the probe. The GO fluorophore has a significant nanoscale—surface energy transfer effect [70]. When the probe is adsorbed on
the GO surface, the fluorescence signal will be quenched due to the transfer of energy
or electrons. After hCG is added, hCG specifically binds to the fluorescent-labeled
335
for positive immunostaining. Recently Rajesh Ahirwar et al. [63] fabricated an electrochemical (voltammetric) aptasensor for accurate and rapid quantification of ERα
in breast tissue lysates. Researchers collected human breast tissues from cancerous
and normal people, respectively. They analyzed the tissue extract for the Erα through
conventional ELISA and aptamer-assisted ELISA methods. Both methods acquired
similar results. The aptasensor measures the change in electron flow caused by the
structural change of the aptamer from unbound state to target-bound state. The electrical signal changes with the target concentration proportionally, so it can accurately
and quickly detect ERα in breast tissue lysates quantitatively. The method of electrochemical aptasensor to measure ERα is compared with other existing ERα detection
schemes, which demonstrates the feasibility of aptasensor for disease diagnosis.
However, the research still needs a considerable sample size to further strengthen the
clinical potential of this aptasensor.
11.3.1.2 Aptamer Used in Pregnancy Diagnosis
Aptamers can also be used in pregnancy diagnosis. In the early stage of pregnancy, P4 can be used as an important detection indicator. Estrogens drive pubertal
development, whereas P4 is the major stimulus for cell proliferation in the adult
mammary gland [64]. Zhu [65] has developed an antibody-aptamer sandwich
cathodic photoelectrochemical biosensor for the detection of P4, which has already
been successfully applied in the determination of P4 in human serum samples.
Early in pregnancy, the body releases large amounts of human chorionic
gonadotropin, a hormone that plays a key role in the maintenance of pregnancy
and a baby’s development. Human chorionic gonadotropin (hCG) is synthesized by
syncytiotrophoblast in the placenta [66]. During the first six weeks of pregnancy, the
ovaries are transformed into gestational luteum after ovulation, and hCG promotes
the secretion of progesterone, estradiol, and estrone [67]. The abnormally high or low
values could also be associated with adverse pregnancy outcomes. The level of hCG
can monitor pregnancy and pregnancy-related disorders. Scientists have developed
hCG-related aptamers and fabricated corresponding biosensors. In 2013, Ding [68]
developed an hCG-binding peptide aptamer to detect aptamer. In contrast to other
detecting methods, this detecting method doesn’t rely on the use of antibody, so it
is more stable and owns better biocompatibility to the inner environment. Xiaokang
Ding identified oligopeptide sequences by use of phage libraries. They selected a
specific phage library against immobilized hand translated their DNA sequences to
oligopeptide sequences. The selected oligopeptide binds to hCG specifically with a
dissociation constant of 0.9 nM. According to Xiaokang Ding’s achievement, Xia
et al. [69] developed a graphene oxide (GO)-based fluorescent platform for the detection of hCG in 2016. They employed a fluorescein isothiocyanate (FITC)-labeled
hCG-specific binding peptide aptamer as the probe. The GO fluorophore has a significant nanoscale—surface energy transfer effect [70]. When the probe is adsorbed on
the GO surface, the fluorescence signal will be quenched due to the transfer of energy
or electrons. After hCG is added, hCG specifically binds to the fluorescent-labeled