low-dimensional graphene allows for the optical and electrophysiological recordings

from electrodes, such as monitoring Ca²⁺ signaling with fluorescent dyes. The various

dimensionality provided by graphene nanostructures has a significant impact on the

electrical, optical, and mechanical properties of the materials. Two-dimensional graphene

nanostructures are chosen for simultaneous electrophysiological, electrical, and optical

recordings. Three-dimensional graphene nanostructures, on the other hand, are favored

for a smaller sensor footprint and higher limit of detection because they provide effective

electrical interactions and low electrode impedance [6].

To illustrate the notion of frequency-division multiplexing of brain impulses, Garcia-

Cortadella et al. [45] combined graphene transistors with custom-built front-end ampli­

fiers. It was accomplished by using graphene transistors to perform on-site amplitude

modulation of the recorded brain signals. The Long Evans rat’s cortex was interfaced with

a 4 × 8 array of graphene solution-gated FETs to capture the spatial patterns map of

cortical spread depression events. The proposed approach removes the need for switches,

minimizing the limits imposed by slow switching speeds and reducing the platform’s

FIGURE 16.6

(A) CV curves of GOx/GCE: (a), GO-GOx/GCE; (b), rGO-GOx/GCE; (c), and rGO-Pt NPs-GOx/GCE; (d) in

deoxygenated 0.1 M PBS (pH 7.4). (B) pH effect of the solution. (C) Scan rate effect of the experiment. (D)

Glucose measurement.

Source: (Reproduced from ACS Sustainable Chemistry and Engineering 2018, 6, 3805–14, https://doi.org/10.

1021/acssuschemeng.7b04164).

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Bioelectronics