primarily produced by the tumor or secondary in response to the presence of the tumor

[38]. These biomarkers can be produced by cancer cells and they can be distinguished in

tumoral tissues or biological fluids (serum, blood, urine, stool, plasma, and sputum). The

use of potential biomarkers in canine mammary tumors can lead to early diagnosis, tumor

grading, prognosis, and monitoring of response to treatment. Biosensors are known ana­

lytical bio-based devices which can recognize the target bio-origin integrated [39]. The

biological action creates measurable changes in a medium, and the transducer transforms

them into measurable electrical signals. Biosensor applications are portable, miniaturized,

and more effective than analytical techniques such as immunohistochemistry or enzyme-

linked immunosorbent assay (ELISA). Biosensor recognition parameters are enzymes,

immunogenetics, DNA, RNA, small biomolecules, and cells. The transmission method

consists of several strategies, including

a. Electrochemical

b. Optical

i. Noble metal NPs-based platforms

ii. Magnetic NPs-based platforms

iii. Antibody immobilization on NPs

c. Mass measurement to detect the circulating tumor cells [40].

Generally, biosensors are medical devices that can be used outside of the hospital setting

and tend to be portable, easy to assemble, flexible, rapid, and low cost. Biosensors can be

identified due to their mechanism that presents biological specificity or the method of

physicochemical signal transmission. According to signal transmission, biosensors can be

classified as electrochemical, mass change, or optical. Electrochemical sensors are the

devices that support the early detection of different public health problems [41].

Nanotechnology is a technology that incorporates innovative products that involve the

exchange of matter at the atomic and molecular levels. Nanomedicine is used in nano­

technology in medical applications, diagnosis, treatment, and prevention of cancer, car­

diovascular and infectious diseases. The excellent properties of nanomaterials are small

size, unique morphology, uniform dispersion, large surface area, convenient functiona­

lization, biocompatibility, preferential deposition in cancer cells, ability to bind functional

portions, and reactivity. They are materials with superior abilities such as overcoming

biological barriers and reaching certain tissues and cells [42]. Metal (Au, Cu, Fe, Pt, Pd,

Ag, Zn, and Ni) NPs can distinguish unique features in terms of magnetic, electro­

chemical, optical, and electrical activities in biomedical applications such as drug/gene

delivery systems, cell imaging, biosensing, and cancer monitoring.

Recently, NPs are very important for their effects in cancer therapy. In recent studies,

Fe, Ni, and Co NPs have been preferred in medical biotechnology. The rising of nano­

technology in the last 20 years has opened up research horizons in the field of nano­

medicine. In recent years, researchers have been discussing the prospects and challenges

of electrochemical biosensors for next-generation cancer diagnosis. Combining electro­

chemical devices with nanoscale materials results in simultaneous measurement for

multiple cancer markers. Advanced properties of electrochemical devices with a nano-

approach infrastructure are extremely valuable for increasing the effectiveness of cancer

diagnosis and treatment monitoring [43]. There are several kinds of biomarkers devel­

oped to monitor breast cancer. Pacheco et al. reported an electrochemical (voltammetric)

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Bioelectronics