using fluorescent markers. This points to a direct link between brain activation and the

charge injected.

Another important application of graphene bioelectronics is in the field of fabrication of

interfaces inflexible and conformal graphene-graphite integrated devices. Sung Woo Nam

et al. [6] developed ultra-thin monolithic graphene-graphite structures, which permitted

the transfer of the whole device onto various non-planar substrates. Also, they have

demonstrated the transfer of the monolithic device on a human eye model, which is

having a potential application in the fabrication of artificial retina where the softness of

the electronic material lends itself for conformal interface with the corresponding me­

chanical properties of biological systems.

Sung Woo et al. [2] also reported the synthesis of three-dimensional (3D) graphene-

based biosensors fabricated via 3D transfer of monolithic graphene-graphite structures.

They found that the developed materials were mechanically flexible; all-carbon structures

were a potential candidate for intimate 3D interfacing with biological systems. The arena

of switchable bioelectronics on graphene interface is at the phase of graphene-stimuli-

responsive polymer hybrids proficient enough to regulate and control the enzyme-based

biomolecular reaction under the effect of temperature, pH, light, etc. Recently, Meenakshi

Choudhary et al. [7] reviewed the progress of switchable graphene-based bioelectronics

interfaces.

Vinod Kumar et al. [13] highlights the existing advances in graphene and graphene

hybrid-based bioelectronics and their properties (in terms of stretchability and con­

ductivity), encounters, and future perspectives. In the arena of graphene-based flexible

and stretchable bioelectronics in health care systems. Danker et al. [48] provided some

perception on fundamental aspects of graphene solution-gated field-effect transistors and

explored them as transducers for the recording of the electrical activity of living cells. The

brilliant chemical, electrical, and mechanical properties, of graphene brand it as a su­

preme material towards the fabrication of bioelectronic devices based on field-effect

transistors. Taemin Kim et al. [17] examined several types of flexible and/or stretchable

substrates that are integrated with CNTs and graphene for the building of high-quality

active electrode arrays and sensors. Young-Tae Kwon et al. [18] recently illustrated the

first demonstration of all printed, nanomembrane electronics employing multiple nano­

materials to construct high-performance, wearable sensors, and wireless circuits. Three-

dimensional, flexible graphene bioelectronics were fabricated on planar substrates by a

wet-transfer method by using a thin Au film as a transfer layer to achieve the 3D gra­

phene structure by Sung Gyu Chun et al. [49]. Dace Gao et al. [1] summarized the

emerging soft conductors for bioelectronic interfaces including CNTs and graphene,

which are customized to interface with skin and other tissues. Graphene nanostructures

for input-output bioelectronics were recently reviewed by Garg et al. [50].

16.7 Conclusion and Outlook

The synergy of graphene-based materials and biology guarantees scalability and co­

operativity in diverse fields of bioelectronics. The promising estates of graphene-based

materials together with the simplicity of integration and functionalization brand them as

suitable candidates in the fabrication of bioelectronic devices. With the advancement in

the field of novel technological devices, graphene-based materials have exposed brilliant

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