23.4 Functions and Devices in Recent Bioelectronic Application...................................384

23.5 Conclusion and Future Aspects....................................................................................386

References ....................................................................................................................................390

23.1 Introduction

Flexible bioelectronics (FB) using electroactive polymer-based biocomposites have been

attracting researchers’ attention recently and garnering great interest as they offer tunable

mechanical flexibility, electrically conducting substrate, biocompatibility, and tailorable

surface functionality, which support the different human tissue or organ along with the

interface to machine [1]. In a biological system, cell function is modulated by various

cues, and among them, bioelectricity affects abundant cellular functions such as pro­

liferation, differentiation, signal transduction, DNA repair, etc. The ion channels and gap

junctions are some of the instructive signals that employ voltage and current in the

complex bioelectronics mechanism where the receptor or transporters ions participate to

interface with organs and regulate the biological development [2]. Intimate integration

with the human body requires mechanical flexibility for shape-matching with the bio­

logical landscape, compatibility with interface stiffness, tissues, and body fluids apart

from maintaining high electrical conductivity and stability. The thinner and more flexible

the device, the less the insertion trauma, damage, and chronic inflammation at the in­

sertion site. Modern-day wearable electronics have made outstanding strides towards

medical diagnostics with advanced design, extremely thin, stretchability, flexibility, and

very high precision in real-time monitoring.

In recent years, a conducting polymer (CP) blends with a traditional polymer matrix

have been extensively explored and have shown good cell-matrix interaction due to their

chemical stability along with the mechanically soft property of the substrate. This has

reduced the inflammatory response along with enhanced physiological signal interface in

the biological environment, and thereby high reproducibility is observed and is proved to

be a promising factor for bioactive devices [2]. Electroactive or CP-based scaffolds are

developed for a multitude of biomedical applications such as tissue engineering, bio­

sensors, energy storage, actuators, electrotherapeutic devices, drug delivery system, and

neural interfaces (Figure 23.1) [3]. The CP displays hybrid ionic-electronic conductivity,

biocompatibility and responds to electrochemical oxidation-reduction processes by a

reversible change in conductivity, color, dimension, etc. Superior electrocatalytic activity

and strong adsorptive ability are also the reasons in their favor over metal electrodes.

Their facile synthetic processes and ease of functionalization and hybridization with other

materials add up to their popularity in the development of FB. CPs and their derivatives

are appropriate for neural interfaces and dry electrodes for biomonitoring since most of

the biological signals, including neural transduction, occur via ionic transport processes.

Bioelectronics devices should be thin, imperceptible, comfortable, and low rigidity and

elastic range, commensurating with the tissue containing crack-onset strain equal to or

greater than that of the skin vis-a-vis substrate where these are integrated. Interestingly,

even the food processing industry can benefit from their use in the storage and fer­

mentation processes of starch-based food [4]. This chapter focuses on CP-based bio­

composite material and fabrication techniques highlighting the design of the substrate

towards bioelectronic applications along with future challenges.

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