Page 62 - Bio Engineering Approaches to Cancer Diagnosis and Treatment

60 CHAPTER 3 Immune assay assisted cancer diagnostic

NASBA, amplification [43]. Arkan et al. have investigated the detection of HER2 in
serum samples of patients with breast cancer [44]. They have used gold as a nanopar-
ticle due to its increased sensitivity, and discovered that by increasing the concentra-
tion of the HER2 antigen, detection is increased in serum samples of patients with
breast cancer.
Electrochemical and optical biosensors and techniques are particularly attractive
for biomarker detection because of their high sensitivity, relatively easy fabricat-
ing, easy operating procedures, and the potential to be miniaturized. Another tech-
nique that can improve the sensitivity of immounosensors is carbon nanomaterials
because of their excellent electric and mechanical properties. The combination of
carbon nanomaterials into biosensor platforms is now popular in biosensor design.
The most widely used carbon nanomaterials to date are nanotubes [single-walled
(SWCNT) and multiple-walled (MWCNT)] and graphs, with carbon quantum-dots
(QD) emerging as novel materials for sensor construction in the field of breast and
ovarian cancers immunology and cancer research. Mucin (MUC) family of glyco-
protein have been investigated as some biomarkers. Ovarian cancers have the worst
prognosis when malignancies are diagnosed at late stage, therefore finding biomark-
ers that help diagnose this cancer at early-stage is essential for patient's survival.
Mucins are large glycoproteins. They have a crucial role in the protection and lubri-
cation of the surface of epithelial tissues including mammary glands, female repro-
ductive tracts, kidneys, lungs, stomach, pancreas, or gall bladder. They also play an
important role in cell differentiation, signaling processes and cell adhesion. Normal
amount of mucin presents in the body, but in ovarian cancer it's overproduction has
been seen in the blood. Therefore, measuring this marker in blood can help in the
rapid diagnosis of cancer. Cristea et al. [45] have investigated the development of
a diagnosis device based on the optical and electrochemical principles for detect-
ing the levels of multiple MUC-type biomarkers in the serum samples of patients.
Combining SPR and electrochemical techniques, the selectivity has improved the
sensitivity and reliability of the obtained transducer. They have shown the combina-
tion of these methods is more accurate than separate ones and it is more cost-effec-
tive. This method became more popular through the use of carbon nanotubes. It has
excellent properties such as a large surface area, high conductivity, and easy chemi-
cal modification as an electrode surface for use in electrochemical immunosensors.
Carbon nanotubes also have high chemical and thermal stability; therefore, it can be
efficiently used in sensor surface modification. To increase the sensitivity, Rusling's
group has developed nanostructured electrodes including densely packed films of
single-wall carbon nanotube (SWCNT) sections (forests) [46]. It is ultrasensitive
in detecting PSA. They have also identified that by attaching the tracer antibody
−1
to these carbon nanotubes with multiple HRP labels, giving a DL of 4 pg mL for
PSA spiked into undiluted calf serum can enhance the sensitivity even more. In a
4-electrode SWCNT forest array for detection of multiple protein biomarkers [PSA,
prostate-specific membrane antigen (PSMA), IL-6 and platelet factor 4 (pf-4)] this
technique has investigated patient's serum samples. The results were positive and
they have detected its accuracy by ELISA. SWCNT forests can capture immobilized