**2.7 Interleukin-6 and -8 (IL-6 and IL-8)**

Interleukin-6 (IL-6) is a leukocyte-secreted 21 kDa glycoprotein, related to as both a pro- and an anti-inflammatory cytokine because it has roles in both directions. Interleukin (IL)-8 is an inflammatory chemokine contained in the subfamily C-X-clinically relevant rates of IL-6 in physiologically normal situations

**97**

mL<sup>−</sup><sup>1</sup>

**Figure 7.**

*Current and Prospective of Breast Cancer Biomarkers DOI: http://dx.doi.org/10.5772/intechopen.91151*

have recently been recorded as 5–25 pg mL<sup>−</sup><sup>1</sup>

*platform. Reprinted with permission from Ref. [34].*

with the detection value of 3 fg mL<sup>−</sup><sup>1</sup>

IL-6 level in the linear range of 0.02–3 pg mL<sup>−</sup><sup>1</sup>

**2.8 Vascular endothelial growth factor (VEGF)**

the presence of tumors of the breast cancer [38].

and good stability (7 weeks) [37].

and up to 1000 pg mL<sup>−</sup><sup>1</sup>

with a detection value of 6 pg mL<sup>−</sup><sup>1</sup>

patients [34]. IL-8 is expressed by certain cell types, including activated monocytes

*Schematic representation of the modified electrochemical biosensor based on MBCPE/Fe3O4-RGO/PANHS* 

For the detection of interleukin 1β in human serum and saliva, new impedimetric immunosensor was prepared using semi-conductive poly (2-thiophen-3-ylmalonic acid) (P3-TMA) as matrix material for immobilization and anti-IL-1β antibody as a component for biorecognition. P3-TMA added a lot of antibody binding in the presence of carboxyl groups. EIS and CV techniques were used d to monitor the detection of IL-1β antigen concentration in the range of 0.01–3 pg

 [36]. Using a similar principle, an impedimetric immunosensor for highly sensitive detection of IL-8 is in human serum and saliva samples. 6-phosphonohexanoic acid (PHA) was used to label the anti-IL-8 antibody. In addition, anti-IL8 antibody interaction to IL8 antigen was observed using SFI (single frequency impedance) technique as shown in **Figure 8**. EIS technique was applied for the interrogation of

Specific tyrosine kinase receptors divided into subtypes of VEGFR-1, VEGFR-

For detection of VEGFR-2, a sandwich immunoassay was designed to detect VEGFR-2, by immobilizing anti-VEGFR-2 Ab1using chitosan/rGO/thionin-modified GCE as shown in **Figure 9**. An HRP-labeled Ab2 was used to identify antibody,

2, and VEGFR-3 are vascular endothelial growth factor receptors (VEGFRs). VEGFR-2 activates most angiogenic processes among the three forms. VEGFR-2 is

an important biomarker for breast cancer with a blood level of >15 ng L<sup>−</sup><sup>1</sup>

and macrophages, a wide range of epithelial cells and fibroblasts [35].

in sepsis

indicating

**Figure 7.**

*Molecular Biotechnology*

screening biomarker.

0.01565–10 pg mL<sup>−</sup><sup>1</sup>

value of 0.003 pg mL<sup>−</sup><sup>1</sup>

mol L<sup>−</sup><sup>1</sup>

**2.7 Interleukin-6 and -8 (IL-6 and IL-8)**

the trace amounts of the DNA target.

amino acid implicated in genomic stability. Mutations in this gene are characterized as closely associated with and early onset of family breast cancer syndrome. These are also responsible for controlling and managing the checkpoints and cell division of the cell cycle. Mutations in the BRCA1 and BRCA2 genes are linked to increase of breast cancer and are essential for about 21–40% of hereditary cases of breast cancer [28]. BRCA1 protein expression was reported to be decreased in 30% of sporadic cases of breast cancer [29]. The extent of the BRCA1 protein reduction depends on the extent of the breast cancer and is inversely to the expression of BRCA2 protein used as a tool for the treatment of sporadic breast cancer [30]. Furthermore, BRCA2 can be used for breast cancer as both a prognostic and a

Currently, Shahrokhian and Salimian [31] developed an ultrasensitive labelfree electrochemical DNA (E-DNA) sensor based on conducting polymer/reduced graphene-oxide platform has been developed for the detection of BRCA1 gene. An electrochemical technique was used as a simple and easy to control method for the electrochemical reduction of graphene oxide and also for the electropolimerization of the monomer of pyrrole 3 carboxylic acid. The signal produced from the E-DNA sensor uses CV, DPV and EIS methods to detect the redox probe's electrochemical behavior. This sensor allows BRCA1 to be quantitatively determined in the linear range of 10 fM to 0.1 μM with a low detection limit as 3 fM. In addition, the modified electrode was effectively used in blood plasma samples to accurately determine

Furthermore, recently developed novel immunoassay based on multiple polymer signal amplification technique for BRCA1 protein recognition. The developed immunoassay processed by poly (dopamine-beta cyclodextrine-cetyl trimethylammonium bromide) doped by silver nanoparticles (P[DA-β-CD/CTAB])-AgNPs and functionalized mesoporous silica matrix (MCM-41-SO3H) produced on the glassy carbon electrode with a large surface area that has been designed to provide a new device for the immobilization of primary antibodies and outstanding conductivity. MCM-41-SO3H provides the appropriate volume of pores and functional groups to detect further horseradish peroxidase-labeled antibodies and improve conductivity to further amplify the electrochemical signal. The experimental immunoassay indicates adequate analytical efficiency for BRCA1 screening with a linear range of

(SWV) and a low quantification

[33].

(DPV) and 0.625–20 pg mL<sup>−</sup><sup>1</sup>

In another study, label free DNA biosensor on a modified magnetic bar carbon paste electrode for BRCA1 mutation detection. In this research works, firstly, Fe3O4- RGO nanoparticles were synthesized, accompanied by physical adsorption of the synthesized nanoparticles composite to the built magnetic bar carbon paste electrode (MBCPE) as shown in **Figure 7**. Using PANHS leads to decreasing electrode preparation, possessing an excellent selectivity for determination of BRCA1. However, the composite of the nanoparticles are linked with using 1-pyrene butyric acid-N-hydroxy succinimide ester (PANHS) as a detection of DNA sequence also (BRCA1 5382 insC mutation detection) strands were immobilized on the surface of the electrode for exact incubation time. By using EIS technique the linear range (1.0 × 10<sup>−</sup>18 mol L−<sup>1</sup>

) and the low detection value of 2.8 × 10<sup>−</sup>19 mol L−<sup>1</sup>

Interleukin-6 (IL-6) is a leukocyte-secreted 21 kDa glycoprotein, related to as both a pro- and an anti-inflammatory cytokine because it has roles in both directions. Interleukin (IL)-8 is an inflammatory chemokine contained in the subfamily C-X-clinically relevant rates of IL-6 in physiologically normal situations

[32].

**96**

–1.0 × 10<sup>−</sup><sup>8</sup>

*Schematic representation of the modified electrochemical biosensor based on MBCPE/Fe3O4-RGO/PANHS platform. Reprinted with permission from Ref. [34].*

have recently been recorded as 5–25 pg mL<sup>−</sup><sup>1</sup> and up to 1000 pg mL<sup>−</sup><sup>1</sup> in sepsis patients [34]. IL-8 is expressed by certain cell types, including activated monocytes and macrophages, a wide range of epithelial cells and fibroblasts [35].

For the detection of interleukin 1β in human serum and saliva, new impedimetric immunosensor was prepared using semi-conductive poly (2-thiophen-3-ylmalonic acid) (P3-TMA) as matrix material for immobilization and anti-IL-1β antibody as a component for biorecognition. P3-TMA added a lot of antibody binding in the presence of carboxyl groups. EIS and CV techniques were used d to monitor the detection of IL-1β antigen concentration in the range of 0.01–3 pg mL<sup>−</sup><sup>1</sup> with the detection value of 3 fg mL<sup>−</sup><sup>1</sup> [36].

Using a similar principle, an impedimetric immunosensor for highly sensitive detection of IL-8 is in human serum and saliva samples. 6-phosphonohexanoic acid (PHA) was used to label the anti-IL-8 antibody. In addition, anti-IL8 antibody interaction to IL8 antigen was observed using SFI (single frequency impedance) technique as shown in **Figure 8**. EIS technique was applied for the interrogation of IL-6 level in the linear range of 0.02–3 pg mL<sup>−</sup><sup>1</sup> with a detection value of 6 pg mL<sup>−</sup><sup>1</sup> and good stability (7 weeks) [37].

### **2.8 Vascular endothelial growth factor (VEGF)**

Specific tyrosine kinase receptors divided into subtypes of VEGFR-1, VEGFR-2, and VEGFR-3 are vascular endothelial growth factor receptors (VEGFRs). VEGFR-2 activates most angiogenic processes among the three forms. VEGFR-2 is an important biomarker for breast cancer with a blood level of >15 ng L<sup>−</sup><sup>1</sup> indicating the presence of tumors of the breast cancer [38].

For detection of VEGFR-2, a sandwich immunoassay was designed to detect VEGFR-2, by immobilizing anti-VEGFR-2 Ab1using chitosan/rGO/thionin-modified GCE as shown in **Figure 9**. An HRP-labeled Ab2 was used to identify antibody,

#### **Figure 8.**

*Schematic representation of the impedimetric immunosensor IL-8 detection. Reprinted with permission from Ref. [38].*

#### **Figure 9.**

*Schematic representation of the electrochemical biosensing for VEGFR2 detection. Reprinted with permission from Ref. [40].*

catalyzing thionine oxidation by H2O2. VEGFR-2 was quantified by DPV with a detection limit of 0.28 pM in the linear concentration range of 0.4–86.0 pM [39]. For its detection, VEGFR, sensitive label-free impedimetric sensor fabricated on molecular impressed polymer (MIP) as a biomimetic receptor coupled with screen-printed electrodes. Next, o-phenylenediamine (oPD) electropolymerization was conducted on graphite-screen-printed electrodes in the presence of VEGF

**99**

**Figure 10.**

*permission from Ref. [43].*

*Current and Prospective of Breast Cancer Biomarkers DOI: http://dx.doi.org/10.5772/intechopen.91151*

**2.9 Cluster differentiation 146 Ag (CD-146)**

a detection limit of 0.08 pg mL<sup>−</sup><sup>1</sup>

linear range in 0.0050–20 ng mL<sup>−</sup><sup>1</sup>

molecules through cyclic voltammetry. The single-use MIP-based sensor demonstrated good analytical efficiency for VEGF detection from 20 to 200 pg mL<sup>−</sup><sup>1</sup>

using with EIS technique [40].

, a low limit detection value of 1.6 pg mL<sup>−</sup><sup>1</sup>

Cluster differentiation 146 Ag (CD-146) is a molecule of cell adhesion that belongs to the superfamily of immunoglobulins. It is identified as a progression marker for melanoma (melanoma adhesion molecule antigen) and breast cancer. The normal level of CD-146 in blood serum of healthy individuals is generally 309 μg L<sup>−</sup><sup>1</sup>

For the identification of CD-146, a sandwich-based amperometric immunosensor was manufactured in which rGO-tetra ethylene pentaamine (TEPA) enhanced GCE antibody (Ab1) was immobilized as shown **Figure 10**. This improvement offered the electrode a large number of amino groups to improve the loading potential of antibodies. The secondary Ab was controlled with colloidal sphere TiO2 and nanoparticles Au/Pd and assay was conducted by calculating the amperometric reaction to electrocatalytic reduction of H2O2. However, the immunosensor displayed a wide

Furthermore, biomimetic mussel-inspired polydopamine coating photoelectrochemical biosensing chip was constructed to detect CD146. The CdS/TiO2-ITO chip was designed using the electrodeposition process to deposit CdS on the TiO2-ITO chip. In addition, the PDA (polydopamine), developed by DA (dopamine) selfpolymerization, was anchored on the CdS/TiO2-ITO (cadmium sulphide/titanium dioxide-indium tinoxide) chip surface through its strong adhesivity and specific interactions such as electrostatic attractions or covalent bindings. Also, without using external crosslinkers, PDA/CdS/TiO2-ITO chips could be used for direct immobilization of antibodies. By measuring the photocurrent responses to different concentrations of CD146, quantitative determination of CD146 was achieved based

on this principle. The photocurrent decreased linearly from 1 pg mL<sup>−</sup><sup>1</sup>

with an increase in CD146 concentration and a detection value of 0.3 pg mL<sup>−</sup><sup>1</sup>

*Schematic representation of the preparation of Au/Pd@TiO2-Ab2 (A) and immunosensor (B). Reprinted with* 

with

[41].

[42].

to 20 ng mL<sup>−</sup><sup>1</sup>

[43].

*Molecular Biotechnology*

**Figure 8.**

*Ref. [38].*

**98**

**Figure 9.**

*from Ref. [40].*

catalyzing thionine oxidation by H2O2. VEGFR-2 was quantified by DPV with a detection limit of 0.28 pM in the linear concentration range of 0.4–86.0 pM [39]. For its detection, VEGFR, sensitive label-free impedimetric sensor fabricated on molecular impressed polymer (MIP) as a biomimetic receptor coupled with screen-printed electrodes. Next, o-phenylenediamine (oPD) electropolymerization was conducted on graphite-screen-printed electrodes in the presence of VEGF

*Schematic representation of the electrochemical biosensing for VEGFR2 detection. Reprinted with permission* 

*Schematic representation of the impedimetric immunosensor IL-8 detection. Reprinted with permission from* 

molecules through cyclic voltammetry. The single-use MIP-based sensor demonstrated good analytical efficiency for VEGF detection from 20 to 200 pg mL<sup>−</sup><sup>1</sup> with a detection limit of 0.08 pg mL<sup>−</sup><sup>1</sup> using with EIS technique [40].
