Topics in Current Chemistry (2020) 378:12
1 3
allowed GOx to be immobilized via physical adsorption. Also, Fe 3 O 4 NPs dispersed
in the PVA matrix promoted electron transfer between the enzyme and electrode.
The GOx/PVA-Fe 3 O 4 /Sn bioelectrode detected glucose in the range from 5 × 10
−3
to
30 mM with a sensitivity of 9.36 μA mM
−1
, and exhibited a lower detection limit of
8 μM at a signal-to-noise ratio of 3.
Shamsipur et al. [239] described a sandwich-type immunoassay for the detection of human epidermal growth factor receptor 2 (HER2)—a key prognostic tumor
marker allowing diagnosis of breast cancer at early stages. The electrochemical
immunosensor employed the synergistic effect of a nanomagnetic platform and
a bioconjugate for the determination of HER2. Fe 3 O 4 nanoparticles were synthesized by a simple chemical co-precipitation method. The magnetite nanoparticles
coated with 3-aminopropyltrimethoxysilane and conjugated to the antibody were
then immobilized on a GCE. The biosensor showed a linear relationship between
the DPV stripping signal of silver and the logarithm of HER2 concentrations was
obtained in the range of 5.0 × 10
−4
–50.0 ng/mL (R
2
= 0.9906) with a detection limit
of 2.0 × 10
−5
ng/mL.
Kumar et al. [240] presented an easy method for the fabrication of an electrochemical paper biosensor to detect CEA biomarker using Fe 3 O 4 NPs decorated
poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Whatman
filter paper (WP) was chosen for preparation of the paper electrode. The incorporation of Fe 3 O 4 NPs into PEDOT:PSS/WP improved electrochemical performance and
signal stability. The nanostructured paper-based electrode was used to immobilize
anti-CEA monoclonal antibodies. The proposed immunoelectrode exhibited efficient
linear detection range (4–25 ng/mL), high sensitivity (10.2 µA ng
−1
mL cm
−2
) and
long shelf life (34 days).
Chikhaliwala et al. [241] constructed an electrochemical immunoassay for the
simultaneous determination of alpha-fetoprotein (AFP) and glypican-3 (GPC-3),
both constitute important biomarkers for early detection of hepatocellular carcinoma
(HCC). The GCE was modified through drop-casting with Fe 3 O 4 NPs decorated
with hyperbranched amino functionalized dendrimers. The Fe 3 O 4 NPs facilitated
magnetic separation of analytes as well as enhanced the electroanalytical effect in
synergy with a large surface area of dendrimers. This sensor exhibited a linear range
from 0.02 to 10 ng/mL for both biomarkers, and a low detection limit of 50 and
70 pg/mL, respectively.
7 Conclusions
This review is dedicated to gold, silver, and iron oxide nanoparticles, their main
physical and chemical characteristics, synthetic routes, and surface modification
with ligands and biomolecules aimed at electrochemical applications. We have provided an overview of the multiple designs and architectures, along with experimental procedures to obtain functional bioconjugates and their use for electrochemical
applications.
A generalized view of the contents of this review shows that no one bionanoconjugation strategy is better than others. Indeed, selection of the methodology to
118
Reprinted from the journal
1 3
allowed GOx to be immobilized via physical adsorption. Also, Fe 3 O 4 NPs dispersed
in the PVA matrix promoted electron transfer between the enzyme and electrode.
The GOx/PVA-Fe 3 O 4 /Sn bioelectrode detected glucose in the range from 5 × 10
−3
to
30 mM with a sensitivity of 9.36 μA mM
−1
, and exhibited a lower detection limit of
8 μM at a signal-to-noise ratio of 3.
Shamsipur et al. [239] described a sandwich-type immunoassay for the detection of human epidermal growth factor receptor 2 (HER2)—a key prognostic tumor
marker allowing diagnosis of breast cancer at early stages. The electrochemical
immunosensor employed the synergistic effect of a nanomagnetic platform and
a bioconjugate for the determination of HER2. Fe 3 O 4 nanoparticles were synthesized by a simple chemical co-precipitation method. The magnetite nanoparticles
coated with 3-aminopropyltrimethoxysilane and conjugated to the antibody were
then immobilized on a GCE. The biosensor showed a linear relationship between
the DPV stripping signal of silver and the logarithm of HER2 concentrations was
obtained in the range of 5.0 × 10
−4
–50.0 ng/mL (R
2
= 0.9906) with a detection limit
of 2.0 × 10
−5
ng/mL.
Kumar et al. [240] presented an easy method for the fabrication of an electrochemical paper biosensor to detect CEA biomarker using Fe 3 O 4 NPs decorated
poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Whatman
filter paper (WP) was chosen for preparation of the paper electrode. The incorporation of Fe 3 O 4 NPs into PEDOT:PSS/WP improved electrochemical performance and
signal stability. The nanostructured paper-based electrode was used to immobilize
anti-CEA monoclonal antibodies. The proposed immunoelectrode exhibited efficient
linear detection range (4–25 ng/mL), high sensitivity (10.2 µA ng
−1
mL cm
−2
) and
long shelf life (34 days).
Chikhaliwala et al. [241] constructed an electrochemical immunoassay for the
simultaneous determination of alpha-fetoprotein (AFP) and glypican-3 (GPC-3),
both constitute important biomarkers for early detection of hepatocellular carcinoma
(HCC). The GCE was modified through drop-casting with Fe 3 O 4 NPs decorated
with hyperbranched amino functionalized dendrimers. The Fe 3 O 4 NPs facilitated
magnetic separation of analytes as well as enhanced the electroanalytical effect in
synergy with a large surface area of dendrimers. This sensor exhibited a linear range
from 0.02 to 10 ng/mL for both biomarkers, and a low detection limit of 50 and
70 pg/mL, respectively.
7 Conclusions
This review is dedicated to gold, silver, and iron oxide nanoparticles, their main
physical and chemical characteristics, synthetic routes, and surface modification
with ligands and biomolecules aimed at electrochemical applications. We have provided an overview of the multiple designs and architectures, along with experimental procedures to obtain functional bioconjugates and their use for electrochemical
applications.
A generalized view of the contents of this review shows that no one bionanoconjugation strategy is better than others. Indeed, selection of the methodology to
118
Reprinted from the journal