electrochemical sensor [31]. Polyaniline has also been used in an electrochemical sensor

for histamine with a low limit of detection of 48.7 µM [32]. There have been several other

research works demonstrating the use of conducting polymers such as polyaniline and

polypyrrole for the detection of neurotransmitters like epinephrine, dopamine, and ser­

otonin. A detailed review of the works was done by Moon et al. [33].

Conducting polymers have also been utilized in sensors for biomolecules like creatinine

and urea, common metabolites from the degradation of muscles and other proteins. In

1995, Yamato et al. reported a creatinine sensor electrode consisting of polypyrrole and

three enzymes: creatininase, creatinase, and sarcosine oxidase. They reported that the

sensor demonstrated considerable sensitivity towards creatinine under a nitrogen at­

mosphere [34]. In a relatively more recent study, Kumar et al. reported a PEDOT and

β-cyclodextrin-based sensor for creatinine. The sensor showed a low detection limit of

50 µM with a linear range from 0.4 mM to 0.1 M [35]. Urea sensor fabricated from

polyaniline and conducting polymer hydrogel has been reported by Das et al. [36]. The

highly sensitive sensor showed and detection limit of 60 nM and a wide linear range from

1.5 to 1,000 µM. In another urea sensor experiment, Dervisevic et al. utilized another

conducting polymer obtained through electropolymerization of 4-(2,5-Di(thiophen-2-yl)-

1H-pyrrol-1-yl)aniline monomers (SNS-Aniline) on a pencil graphite electrode (PGE). The

SNS-Aniline/PGE was then modified with di-amino-ferrocene (DAFc). The sensor

showed a detection limit of 12 μM [37,38].

Cevik et al. have also demonstrated the usefulness of conducting polymer in sensor

development by detecting cholesterol using a conducting polymer. In their work, they

used 4-(4H-dithienol [3,2-b:2’,3’-d]pyrrole-4)aniline polymer (DTP(aryl)aniline) with

cholesterol oxidase enzyme for the detection of cholesterol. The limit of detection was

0.27 µM and a linear range of 2.0 µM–23.7 µM. Conducting polymer-based sensors have

been reported for other biogenic molecules such as glucose, uric acid, ascorbic acid, ca­

techol, and oligonucleotides [17]. A summary of some biomolecules and their conducting

polymer-based sensors are presented in Table 19.2.

TABLE 19.1

Some Examples of Conducting Poly-Based Biosensors for Drug Detection

Polymer used

Composite

Analyte

Sensor type

LOD (M)

Ref.

PEDOT

PEDOT-MnO2

Paracetamol

Electrochemical sensor

3.1 × 10⁻⁸

[ 19]

PEDOT

PEDOT-MnO2

Sulfamethazine

Electrochemical sensor

1.6 × 10⁻⁷

[ 20]

poly(p-ABSA)

poly(p-ABSA)-rGO

Levofloxacin

Electrochemical sensor

1.2 × 10⁻⁷

[ 22]

poly-TTCA

Cu-poly-TTCA

Acetaminophen

Electrochemical sensor

5.0 × 10⁻⁶

[ 21]

PEDOT

PEDOT:TsO

Ampicillin

Electrochemical sensor

<1.145 × 10⁻⁸

[ 23]

PANi

PANi/CPE

Amoxicillin

Electrochemical sensor

3.5 × 10⁻¹⁰

[ 24]

poly-ATD

poly-ATD/CNPE

Dacarbazine

Electrochemical sensor

3.5 × 10⁻¹⁰

[ 25]

poly-TTBA

AuNPs/polyTTBA

Daunomycin

Electrochemical sensor

5.23 × 10⁻¹¹

[ 26]

polythiophene

UCNP@CP

Alprenolol

Optical sensor

2.2 × 10⁻¹⁰

[ 27]

PANi

AgNPs@PANINTs

5-fluorouraci

Electrochemical sensor

6.0 × 10⁻⁸

[ 28]

Notes: PEDOT: poly(3,4-ethylenedioxythiophene), poly(p-ABSA): poly(p-aminobenzene sulfonic acid), rGo: reduced

graphene oxide, poly-TTCA: poly (terthiophene carboxylic acid), TsO: tosylate, PANi: polyaniline, CPE: carbon

paste electrode, poly-ATD: poly(2-amino-1,3,4-thiadiazole), CNPE: carbon nanotube paste electrode, poly-TTBA:

2,2’:5’,2”-terthiophene-3’-(p-benzoic acid), CP: conjugated polythiophene, UCNPs: upconversion nanoparticles,

AgNP: silver nanoparticles, PANINTs: polyanilime nanotubes.

Conducting Polymer Composites

317