Biomedical Engineering Reference
In-Depth Information
of CEA stops before birth. CEA is one of the most widely used tumor
markers worldwide. Its main application is mostly in gastrointestinal can-
cers, especially in colorectal malignancy, colorectal carcinoma, pancreatic
carcinoma, lung carcinoma and breast carcinoma.
In 2009,
Ling
et al.
[71]
developed an immunosensor for CEA based
on the electrostatic adsorption between the positively charged MnO
2
nanoparticles and Chi composite membrane (nano-MnO
2
/Chi) and the
negatively charged PB. h us, nano-MnO
2
/Chi membrane was adsorbed
onto PB-modii ed electrode surface and GNPs were electrodeposited to
immobilize anti-CEA. Under the optimized conditions, determination of
CEA displayed a linear response in two ranges, from 0.25 to 8.0 ng mL
-1
and from 8.0 to 100 ng mL
-1
, with a detection limit of 0.08 ng mL
-1
. Real
serum samples were measured with the immunosensor approach and
compared against ELISA, with no signii cant dif erence observed between
the two methods.
h en Zhuo
et al.
[72] presented a bienzyme functionalized three-layer
composite magnetic nanoparticles for electrochemical determination
of AFP and CEA. Authors developed a three-layer magnetic nanoparti-
cle composed of a Fe
3
O
4
magnetic core, a PB interlayer and a gold shell
(Fe
3
O
4
/PB/Au). In addition, they used a new signal amplii cation strategy
based on a bienzyme system using HRP and GOx functionalized nanopar-
ticles for electrochemical immunosensing using anti-CEA and anti-AFP,
respectively.
Finally, in 2011,
Ta n g
et al.
[73] showed the utility of a sensitive elec-
trochemical immunoassay for CEA detection with signal dual-amplii ca-
tion using GOx and PB. h e i rst signal amplii cation was based on the
labeled GOx on the anti-CEA-gold-silver hollow microspheres (anti-CEA/
GOx/Au@Ag@HS) toward the catalytic oxidation of glucose. h us the
enzymatic-generated H
2
O
2
was catalytically reduced by the immobilized
PB on the graphene nanosheets. With a sandwich-type immunoassay for-
mat, optimized electrochemical immunosensor exhibited a wide dynamic
range of 0.005 to 50 ng mL
−1
with a low detection limit of 1.0 pg mL
−1
.
Finally, immunosensors were evaluated for clinical serum specimens, and
showed good correlation with those obtained by the electrochemilumines-
cent method (ECL).
12.5.3
Carbohydrate Antigen 19-9
Carbohydrate antigen 19-9 (CA19-9) is one of the most important car-
bohydrate tumor markers associated with biliary, liver, lung and breast
cancers, and various other gastro-intestinal malignancies. Furthermore,
