components including field-effect transistors (FETs), electrodes, electrode arrays, and optical

resonators to create efficient biosensing devices [1]. These devices control and monitor bio­

logical processes and physiological responses through electrical/optical signals. Figure 3.1

shows the various elements of a bioelectronic device. Bioelectronics was first recognized by

Galvani in the 1780s [2]. This experiment sparked a wave of new research into the role of

electricity in biological processes. Later in 1843, the discovery of the action potential has open

gateways for electrical stimulation into therapy through devices such as the cardiac pace­

makers and implants [3]. In clinical practice, neuronal and cardiac stimulators relieved the

pains of millions of patients suffering from cerebrovascular disease, epilepsy, Alzheimer’s

disease, Parkinson’s disease, depression, and a variety of other neurological disorders [4].

Bioelectronic devices represent significant breakthroughs, yet there is still potential for

development in terms of long-term stability. Current technology suffers from major in­

compatibilities at the interface between tissues and electronics in terms of chemical structure,

Young’s moduli, and electrical conductivity [6]. The stability of bioelectronic devices can be

improved by minimizing mechanical mismatches between soft tissues and hard electronic

devices. Moreover, the majority of electricity in the biological system is carried through ions

rather than electrons. In water-rich conditions, the ions are highly conductive in comparison

to electrons and holes. These dissimilarities restrict information flow between biology and

electronics, limiting the extent and longevity of bioelectronic devices. Therefore, the scientific

community has thought of hunting soft and ion-conducting materials to meet mechanical

properties and boost electron-to-ion conversion at the biological contact [7].

In the current scenario, two-dimensional (2D) materials have pushed materials research

to new heights. 2D materials have brought immense possibilities in composition, mi­

crostructures, and properties that make them a potential candidate for a wide range of

applications [8]. Since the discovery of 2D graphene, the development of novel 2D ma­

terials has arisen as a fiercely contested topic in materials research. Material scientists

FIGURE 3.1

Various elements of bioelectronic devices. Adapted with permission from Ref. [ 5]. Copyright (2021) Copyright

the Authors, some rights reserved; exclusive licensee [MDPI]. Distributed under a Creative Commons

Attribution License 3.0 (CC BY) https://creativecommons.org/licenses/by/3.0/).

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Bioelectronics