Several studies have been reported on green biosensors for early-stage cancer diag­

nostics in sensor technology. Bondancia et al. developed a high-performance bacterial

nanocellulose-based biosensor for the immunosensing of the p53 cancer biomarker in

concentration range from 0.01 to 1,000 Ucell. mL⁻¹ with a low LOD of 0.16 Ucell mL⁻¹

[28]. Pothipor et al. fabricated a novel Au NPs-dye/poly(3-aminobenzylamine)/two-

dimensional (2D) MoSe2/graphene oxide (GO)–based electrochemical biosensor for the

cancer antigen 15-3 and microRNA-21 detection [29]. Results showed that the proposed

biosensor exhibited a good linear response with low LOD values of 0.14 U mL−1 for CA

15-3 and 1.2 fM for miRNA-21 for point-of-care medical diagnostic applications [29].

Giang et al. highlighted the performance of the visible and pyrophosphates (PPi) re­

sponsive TiO2/Cu²⁺-carbon dots-based biosensor for wireless electrochemical cancer

detection [30]. Chen et al. investigated the electrochemical performance of the

polydopamine-Au composite-based biosensor for the detection of the pancreatic cancer-

associated microRNA in human biological fluids with a low LOD of 0.26 pM [31]. The

mechanism electrochemical of the proposed biosensor was based on the single

polymerase-boosted dual amplification reaction of DNA [31]. Esmaeili et al. developed a

novel mesoporous silica@chitosan@Au NPs-based “on/off” optical biosensor for the

targeted cancer imaging with remarkable ability in the stable structure with the target

analyte. The mechanism was based on the electrostatic interactions between silanol

groups of the nanostructure and positively charged membrane of cancer cells [32]. Javar

et al. fabricated a novel electrochemical DNA biosensor using Eu³⁺-doped NiO for the

detection of the anti-cancer drug (amsacrine) [24]. Electrochemical measurements proved

that the prepared electrochemical DNA biosensor had significant potential for cancer

detection in a wide concentration range from 0.1 μM to 100.0 μM with a low LOD of

0.05 μM due to the intercalations of amsacrine with ds-DNA. In another study, Amethiya

et al. reported the evaluation of the performance of different biosensors such as a field-

effect transistor (FET), electrochemical, and sandwich electrochemical for the determi­

nation of different types of target analytes such as cancer biomarkers, DNA, cancer cells,

and biological fluids. In addition, they focused on the ability to characterize the tumor

size using different types of machine learning algorithms in sensor applications [33].

10.5 Biosensors in Canine Mammary Tumors

Mammary tumors are neoplasms frequently encountered in female dogs. Mammary tu­

mors are the most common type of neoplasm in female dogs. The malignancy prevalence

differs from 26–73% [34,35]. The primary and the most cost-effective treatment choice is

mastectomy, but the overall survival rate after surgery is low due to local recurrence and

early metastasis. Therefore, there is a need in veterinary medicine for following up on the

tumor development and treatment consequences [34,35]. Since canine mammary tissue

and human mammary tissue are mostly similar, biomarkers used for diagnosis, treatment

options, and determination of prognosis are common. Tumor markers are products of

normal cell metabolism and their production increases due to malignant transformation

[36]. These; are biomarkers that play a role in intracellular adhesion, such as integrins,

selectins, immunoglobulin-like particles, cadherins, cancer antigen 15-3 (CA 15-3), and

carcinoembryonic antigen (CEA) [37]. These indicators reflect the malignancy and are

characterized by substances found in the tumor, blood, or other body fluids that are

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