parameters were calculated with a linear response (0.00005–10 ng/mL) and a low LOD of

16.7 fg/mL in the presence of the PSA [18]. In the past decades, Xies et al. [19] developed

a novel multi-residue electrochemical biosensor based on a composite of graphene/

chitosan/parathion, which supported the sensitivity of working electrodes for organo­

phosphorus pesticides. The detection of organophosphorus pesticides had a linear range

from 1 to 1500 ng/mL with low LODs of 0.012–0.23 ng/mL in the presence of different

organophosphorus. Furthermore, the proposed biosensor was examined for the detection

of chlorpyrifos and dichlorvos in real food samples (apple samples), and the recovery rate

of the proposed biosensor was found to be 87.24%–110.20%.

While the COVID-19 pandemic threatens human and animal health, the progress of the

detection of coronavirus disease (COVID-19) using green and sensitive methodologies are

vital issues for medical diagnosis at an early stage. In 2021, Tran et al. [20] did a literature

review about conducting polymer and COVID-19 virus and discussed a critical issue of

green strategies for the detection of COVID-19 using polymer-based biosensors. This

green detection method reflects the use of green methods to improve the bio-based

surface properties and affect the development of the affinity-based surface modification

strategy of the electrochemical biosensor under physiological conditions as well. To un­

derstand the detection mechanism of COVID-19 electrochemical biosensors, the scientists

focused on the interactions of the virus, antigen, viral RNA, and antibody [20]. Bio-

organic/compatible transistors are one of the most emerging technologies for the medical

diagnosis of cancer and COVID-19 at an early stage with clinical advantages. For this

purpose, Tian et al. fabricated a novel electrochemical enzymatic biosensor using metal-

organic frameworks MIL-53 – Au@Pt nanoparticles for the detection of SARS-CoV-2

nucleocapsid protein (2019-nCoV-NP) using horseradish peroxidase (HRP) and hemin/

G-quadruplex DNAzyme [21].

10.3 Organic Transistors or Biosensors for Cancer Detection

Cancer is a disease that has a terrifying sound to all human beings. In definition, it might

be new for us regarding the recent decades; however, findings are showing that it has

been among us for millions of years. Throughout the history of humanity, there are major

causes of death to balance the population. Unlike infectious diseases, parasites, and en­

vironmental diseases, cancer is not an organism causing the disease, but the tumor cell

itself as a part of the body creating the disease. There are over 11 million people who are

diagnosed with some kind of cancer every year, and it is expected to increase every year.

Since it is a serious health issue of human beings, understanding the nature of the disease,

assessing the risks, prevention, and early diagnosis take an important place for scientists

who are focusing on this specific subject [22].

A tumor by definition is an abnormal growth of cells where they have no functional

purpose and spread to other parts of the body; however, when it becomes cancerous, the

cells become different than the organ or the body part they locate which is called un­

differentiation showing the aggressiveness of the tumor cells. The morphological and

functional resemblance of the tumor to the cell that it is originated is called differentia­

tion. Tumor with benign character is usually well differentiated and resemble the cells

that are originated. Endocrine cancer cell synthesizing hormone, squamous cell cancers

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