some advances in the use of conducting polymers for the detection of metabolites. The

metabolites are discussed in three groups: application of conducting polymers for de­

tection of pharmaceuticals and their metabolites, the use of conducting polymers for

intrinsic biogenic molecule and biomarker sensing, and finally the application of con­

ducting polymer-based sensors for food degradation and food spoilage pathogens.

19.4.1 Conducting Polymer-Based Sensors for Pharmaceutical Drug and

Their Metabolite

Conducting polymers have attracted tremendous interest in biosensor application. Due to

their impressive electrical conductivity, mechanical strength, lightweight, and processa­

bility, they have been hugely applied to electrochemical devices and sensors [19]. Over

the year, they have become popular in the drug detection field and have been applied in

several drug sensors. The conducting poly (3,4-ethylenedioxythiophene) (PEDOT)

was used in an amperometric sensor for paracetamol. The MnO2 nanoflowers doped

PEDOT-based sensor was highly sensitive with a low and reproducible detection limit of

31 nM [19]. The veterinary antimicrobial drug sulfamethazine was previously detected

using a similar electrode (PEDOT-MnO2) and techniques, as mentioned. The sensor

showed a very wide linear range of 1.0 µM to 500 µM and a detection limit of 0.16 µM

with no interference from the commonly known interfering agent [20].

Poly(terthiophene carboxylic acid) (poly-TTCA)) complexed with copper ion was de­

monstrated as a highly selective electrochemical sensor for acetaminophen by Boopathi

et al. [21]. Han et al. fabricated a novel polymer poly(p-aminobenzene sulfonic acid)

for electrochemical determination of levofloxacin. The polymer was fabricated through

electropolymerization. This polymer-based electrochemical sensor was also sensitive

and highly selective [22]. In another antibiotic drug analysis, a tosylate doped poly(3,4-

ethylenedioxythiophene) (PEDOT: TsO) was demonstrated as an effective electrode

material for an impedimetric ampicillin sensor [23].

There are several other research demonstrating the use of conducting polymers for the

detection of drugs such as amoxicillin, dacarbazine, 5-fluorouracil, and alprenolol. Some

of these experiments are summarized in Table 19.1.

19.4.2 Conducting Polymer-Based Sensors For Biogenic Molecules and Biomarkers

Sensors for biomolecule such as proteins, hormones, oligonucleotides, neurotransmitters,

and organic acids are mostly useful for the diagnosis of various diseases. Conducting

polymers have been extensively utilized in this field. For instance, the determination of

serum acetylcholine levels is of diagnostic importance for managing, patients suffering

from memory loss or Alzheimer’s disease. A previous report has shown the detection

of the neurotransmitter and acetylcholine using poly(3,4-ethylenedioxythiophene)

(PEDOT) based composite [29]. In their research, Chauhan et al. reported exceptional

selectivity and sensitivity of an electrode material consisting of ferric oxide, poly(3,4-

ethylenedioxythiophene, and reduced graphene oxide. They obtained a limit of detection

of 4.0 nM from a linear range of 4.0 nM to 800 µM. In another research, PEDOT is again

used in a sensor for dopamine. Xu et al. detected dopamine in the presence of ascorbic

acid using a composite of PEDOT and carbon nanotube (PEDOT/CNT). From the dif­

ferential pulse voltammetry, they obtained a linear range from 0.1 to 20 µM and a de­

tection limit of 20 nM [30]. Another neurotransmitter, histamine was detected by

Zeng et al. using the enzyme methylamine dehydrogenase and polypyrrole-based

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Bioelectronics