π-conjugated backbone structure. The disruption of this structure improves its flexibility

but significantly lowers its conductivity. PTh is a conjugated polyelectrolyte with a

pendant sulfonate group, capable of detecting a biological molecule/event due to its

high-performance accumulation-mode organic electrochemical transistor mode in aqu­

eous media [6]. Its electronic properties can be modulated by doping and/or chemical

modifications.

23.2.2 PANi

PANi is considered as one of the well explored and first tested microelectronic devices

owing to its easy synthesis, low cost, and environmentally friendly nature. PANi has been

widely explored in the last decade for various applications due to its good optoelectrical

properties. PANi is now gaining more importance in the field of bioelectronics. The

combination of mechanical flexibility along with conductivity is an important pre­

requisite factor for organic electronic interfaces [7]. PANi exhibits both properties of

electrically conductive and insulating material, which is dependent upon its oxidation

state. It can be observed or detected in the form of leucoemeraldine (LE, yellow), per­

nigraniline (PG) purple, and emeraldine (EM) dark green.

23.2.3 PPy

One of the most promising CP variants for bioelectronic application is PPy. With the

advances in the development of electron-conducting materials, PPy with high con­

ductivity, excellent biocompatibility, and good mechanical stability were synthesized [8].

Therefore, PPy and its biocomposites were explored as sensors, actuators, and electrodes.

To develop human skin–like materials for modern flexible electronics, PPy-based mate­

rials must be modified due to their high brittleness, non-transparent nature, and lower

solubility in aqueous solutions, restricting the use of PPy for stretchable electronics and

becoming one of the areas to explore more [8]. The selection of synthesis strategies and

composite matrix varies based on their application such as wearable electronics, super­

capacitors, electrodes for energy conservation, etc.

FIGURE 23.2

Schematic representation of fundamental factors to fabricate flexible bioelectronics and their structural design.

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Bioelectronics